# -*- coding: utf-8 -*-
"""
Tests for the Editor and REPL logic.
"""
import sys
import os
import codecs
import contextlib
import json
import locale
import re
import shutil
import subprocess
import tempfile
from unittest import mock
import uuid

import pytest
import mu.logic
from PyQt5.QtWidgets import QMessageBox
from PyQt5.QtCore import pyqtSignal, QObject

from mu import __version__

SESSION = json.dumps({
    'theme': 'night',
    'mode': 'python',
    'paths': [
        'path/foo.py',
        'path/bar.py',
    ],
    'envars': [
        ['name', 'value'],
    ],
})
ENCODING_COOKIE = '# -*- coding: {} -*-{}'.format(mu.logic.ENCODING,
                                                  mu.logic.NEWLINE)


#
# Testing support functions
# These functions generate testing scenarios or mocks making
# the test more readable and easier to spot the element being
# tested from among the boilerplate setup code
#

def _generate_python_files(contents, dirpath):
    """Generate a series of .py files, one for each element in an iterable

    contents should be an iterable (typically a list) containing one
    string for each of a the number of files to be created. The files
    will be created in the dirpath directory passed in which will neither
    be created nor destroyed by this function.
    """
    for i, c in enumerate(contents):
        name = uuid.uuid1().hex
        filepath = os.path.join(dirpath, "%03d-%s.py" % (1 + i, name))
        #
        # Write using newline="" so line-ending tests can work!
        # If a binary write is needed (eg for an encoding test) pass
        # a list of empty strings as contents and then write the bytes
        # as part of the test.
        #
        with open(filepath, "w", encoding=mu.logic.ENCODING, newline="") as f:
            f.write(c)
        yield filepath


@contextlib.contextmanager
def generate_python_files(contents, dirpath=None):
    """Create a temp directory and populate it with .py files, then remove it
    """
    dirpath = dirpath or tempfile.mkdtemp(prefix="mu-")
    yield list(_generate_python_files(contents, dirpath))
    shutil.rmtree(dirpath)


@contextlib.contextmanager
def generate_python_file(text="", dirpath=None):
    """Create a temp directory and populate it with on .py file, then remove it
    """
    dirpath = dirpath or tempfile.mkdtemp(prefix="mu-")
    for filepath in _generate_python_files([text], dirpath):
        yield filepath
        break
    shutil.rmtree(dirpath)


@contextlib.contextmanager
def generate_session(theme="day", mode="python", file_contents=None,
                     filepath=None, envars=[['name', 'value'], ], minify=False,
                     microbit_runtime=None, zoom_level=2, **kwargs):
    """Generate a temporary session file for one test

    By default, the session file will be created inside a temporary directory
    which will be removed afterwards. If filepath is specified the session
    file will be created with that fully-specified path and filename.

    If an iterable of file contents is specified (referring to text files to
    be reloaded from a previous session) then files will be created in the
    a directory with the contents provided.

    If None is passed to any of the parameters that item will not be included
    in the session data. Once all parameters have been considered if no session
    data is present, the file will *not* be created.

    Any additional kwargs are created as items in the data (eg to generate
    invalid file contents)

    The mu.logic.get_session_path function is mocked to return the
    temporary filepath from this session.

    The session is yielded to the contextmanager so the typical usage is:

    with generate_session(mode="night") as session:
        # do some test
        assert <whatever>.mode == session['mode']
    """
    dirpath = tempfile.mkdtemp(prefix="mu-")
    session_data = {}
    if theme:
        session_data['theme'] = theme
    if mode:
        session_data['mode'] = mode
    if file_contents:
        paths = _generate_python_files(file_contents, dirpath)
        session_data['paths'] = list(paths)
    if envars:
        session_data['envars'] = envars
    if minify is not None:
        session_data['minify'] = minify
    if microbit_runtime:
        session_data['microbit_runtime'] = microbit_runtime
    if zoom_level:
        session_data['zoom_level'] = zoom_level
    session_data.update(**kwargs)

    if filepath is None:
        filepath = os.path.join(dirpath, "session.json")
    if session_data:
        with open(filepath, "w") as f:
            f.write(json.dumps(session_data))
    session = dict(session_data)
    session['session_filepath'] = filepath
    with mock.patch("mu.logic.get_session_path", return_value=filepath):
        yield session
    shutil.rmtree(dirpath)


def mocked_view(text, path, newline):
    """Create a mocked view with path, newline and text
    """
    view = mock.MagicMock()
    view.current_tab = mock.MagicMock()
    view.current_tab.path = path
    view.current_tab.newline = newline
    view.current_tab.text = mock.MagicMock(return_value=text)
    view.add_tab = mock.MagicMock()
    view.get_save_path = mock.MagicMock(return_value=path)
    view.get_load_path = mock.MagicMock()
    view.add_tab = mock.MagicMock()
    return view


def mocked_editor(mode="python", text=None, path=None, newline=None):
    """Return a mocked editor with a mocked view

    This is intended to assist the several tests where a mocked editor
    is needed but where the length of setup code to get there tends to
    obscure the intent of the test
    """
    view = mocked_view(text, path, newline)
    ed = mu.logic.Editor(view)
    ed.select_mode = mock.MagicMock()
    mock_mode = mock.MagicMock()
    mock_mode.save_timeout = 5
    mock_mode.workspace_dir.return_value = '/fake/path'
    mock_mode.api.return_value = ["API Specification"]
    ed.modes = {
        mode: mock_mode,
    }
    return ed


def test_CONSTANTS():
    """
    Ensure the expected constants exist.
    """
    assert mu.logic.HOME_DIRECTORY
    assert mu.logic.DATA_DIR
    assert mu.logic.WORKSPACE_NAME


def test_write_and_flush():
    """
    Ensure the write and flush function tries to write to the filesystem and
    flush so the write happens immediately.
    """
    mock_fd = mock.MagicMock()
    mock_content = mock.MagicMock()
    with mock.patch('mu.logic.os.fsync') as fsync:
        mu.logic.write_and_flush(mock_fd, mock_content)
        fsync.assert_called_once_with(mock_fd)
    mock_fd.write.assert_called_once_with(mock_content)
    mock_fd.flush.assert_called_once_with()


def test_save_and_encode():
    """
    When saving, ensure that encoding cookies are honoured, otherwise fall back
    to the default encoding (UTF-8 -- as per Python standard practice).
    """
    encoding_cookie = '# -*- coding: latin-1 -*-'
    text = encoding_cookie + '\n\nprint("Hello")'
    mock_open = mock.MagicMock()
    mock_wandf = mock.MagicMock()
    # Valid cookie
    with mock.patch('mu.logic.open', mock_open), \
            mock.patch('mu.logic.write_and_flush', mock_wandf):
        mu.logic.save_and_encode(text, 'foo.py')
    mock_open.assert_called_once_with('foo.py', 'w', encoding='latin-1',
                                      newline='')
    assert mock_wandf.call_count == 1
    mock_open.reset_mock()
    mock_wandf.reset_mock()
    # Invalid cookie
    encoding_cookie = '# -*- coding: utf-42 -*-'
    text = encoding_cookie + '\n\nprint("Hello")'
    with mock.patch('mu.logic.open', mock_open), \
            mock.patch('mu.logic.write_and_flush', mock_wandf):
        mu.logic.save_and_encode(text, 'foo.py')
    mock_open.assert_called_once_with('foo.py', 'w',
                                      encoding=mu.logic.ENCODING,
                                      newline='')
    assert mock_wandf.call_count == 1
    mock_open.reset_mock()
    mock_wandf.reset_mock()
    # No cookie
    text = 'print("Hello")'
    with mock.patch('mu.logic.open', mock_open), \
            mock.patch('mu.logic.write_and_flush', mock_wandf):
        mu.logic.save_and_encode(text, 'foo.py')
    mock_open.assert_called_once_with('foo.py', 'w',
                                      encoding=mu.logic.ENCODING,
                                      newline='')
    assert mock_wandf.call_count == 1


def test_sniff_encoding_from_BOM():
    """
    Ensure an expected BOM detected at the start of the referenced file is
    used to set the expected encoding.
    """
    with mock.patch('mu.logic.open',
                    mock.mock_open(read_data=codecs.BOM_UTF8 + b'# hello')):
        assert mu.logic.sniff_encoding('foo.py') == 'utf-8-sig'


def test_sniff_encoding_from_cookie():
    """
    If there's a cookie present, then use that to work out the expected
    encoding.
    """
    encoding_cookie = b'# -*- coding: latin-1 -*-'
    mock_locale = mock.MagicMock()
    mock_locale.getpreferredencoding.return_value = 'UTF-8'
    with mock.patch('mu.logic.open',
                    mock.mock_open(read_data=encoding_cookie)), \
            mock.patch('mu.logic.locale', mock_locale):
        assert mu.logic.sniff_encoding('foo.py') == 'latin-1'


def test_sniff_encoding_from_bad_cookie():
    """
    If there's a cookie present but we can't even read it, then return None.
    """
    encoding_cookie = '# -*- coding: silly-你好 -*-'.encode('utf-8')
    mock_locale = mock.MagicMock()
    mock_locale.getpreferredencoding.return_value = 'ascii'
    with mock.patch('mu.logic.open',
                    mock.mock_open(read_data=encoding_cookie)), \
            mock.patch('mu.logic.locale', mock_locale):
        assert mu.logic.sniff_encoding('foo.py') is None


def test_sniff_encoding_fallback_to_locale():
    """
    If there's no encoding information in the file, just return None.
    """
    mock_locale = mock.MagicMock()
    mock_locale.getpreferredencoding.return_value = 'ascii'
    with mock.patch('mu.logic.open',
                    mock.mock_open(read_data=b'# hello')), \
            mock.patch('mu.logic.locale', mock_locale):
        assert mu.logic.sniff_encoding('foo.py') is None


def test_sniff_newline_convention():
    """
    Ensure sniff_newline_convention returns the expected newline convention.
    """
    text = 'the\r\ncat\nsat\non\nthe\r\nmat'
    assert mu.logic.sniff_newline_convention(text) == '\n'


def test_sniff_newline_convention_local():
    """
    Ensure sniff_newline_convention returns the local newline convention if it
    cannot determine it from the text.
    """
    text = 'There are no new lines here'
    assert mu.logic.sniff_newline_convention(text) == os.linesep


def test_get_admin_file_path():
    """
    Finds an admin file in the application location, when Mu is run as if
    NOT frozen by PyInstaller.
    """
    fake_app_path = os.path.dirname(__file__)
    fake_app_script = os.path.join(fake_app_path, 'run.py')
    wrong_fake_path = 'wrong/path/to/executable'
    fake_local_settings = os.path.join(fake_app_path, 'settings.json')
    with mock.patch.object(sys, 'executable', wrong_fake_path), \
            mock.patch.object(sys, 'argv', [fake_app_script]):
        result = mu.logic.get_admin_file_path('settings.json')
        assert result == fake_local_settings


def test_get_admin_file_path_frozen():
    """
    Find an admin file in the application location when it has been frozen
    using PyInstaller.
    """
    fake_app_path = os.path.dirname(__file__)
    fake_app_script = os.path.join(fake_app_path, 'mu.exe')
    wrong_fake_path = 'wrong/path/to/executable'
    fake_local_settings = os.path.join(fake_app_path, 'settings.json')
    with mock.patch.object(sys, 'frozen', create=True, return_value=True), \
            mock.patch('platform.system', return_value='not_Darwin'), \
            mock.patch.object(sys, 'executable', fake_app_script), \
            mock.patch.object(sys, 'argv', [wrong_fake_path]):
        result = mu.logic.get_admin_file_path('settings.json')
        assert result == fake_local_settings


def test_get_admin_file_path_frozen_osx():
    """
    Find an admin file in the application location when it has been frozen
    using PyInstaller on macOS (as the path is different in the app bundle).
    """
    fake_app_path = os.path.join(os.path.dirname(__file__), 'a', 'b', 'c')
    fake_app_script = os.path.join(fake_app_path, 'mu.exe')
    wrong_fake_path = 'wrong/path/to/executable'
    fake_local_settings = os.path.abspath(os.path.join(
        fake_app_path, '..', '..', '..', 'settings.json'))
    with mock.patch.object(sys, 'frozen', create=True, return_value=True), \
            mock.patch('platform.system', return_value='Darwin'), \
            mock.patch.object(sys, 'executable', fake_app_script), \
            mock.patch.object(sys, 'argv', [wrong_fake_path]):
        result = mu.logic.get_admin_file_path('settings.json')
        assert result == fake_local_settings


def test_get_admin_file_path_with_data_path():
    """
    Find an admin file in the data location.
    """
    mock_open = mock.mock_open()
    mock_exists = mock.MagicMock()
    mock_exists.side_effect = [False, True]
    mock_json_dump = mock.MagicMock()
    with mock.patch('os.path.exists', mock_exists), \
            mock.patch('builtins.open', mock_open), \
            mock.patch('json.dump', mock_json_dump), \
            mock.patch('mu.logic.DATA_DIR', 'fake_path'):
        result = mu.logic.get_admin_file_path('settings.json')
        assert result == os.path.join('fake_path', 'settings.json')
    assert not mock_json_dump.called


def test_get_admin_file_path_no_files():
    """
    No admin file found, so create one.
    """
    mock_open = mock.mock_open()
    mock_json_dump = mock.MagicMock()
    with mock.patch('os.path.exists', return_value=False), \
            mock.patch('builtins.open', mock_open), \
            mock.patch('json.dump', mock_json_dump), \
            mock.patch('mu.logic.DATA_DIR', 'fake_path'):
        result = mu.logic.get_admin_file_path('settings.json')
        assert result == os.path.join('fake_path', 'settings.json')
    assert mock_json_dump.call_count == 1


def test_get_admin_file_path_no_files_cannot_create():
    """
    No admin file found, attempting to create one causes Mu to log and
    make do.
    """
    mock_open = mock.MagicMock()
    mock_open.return_value.__enter__.side_effect = FileNotFoundError('Bang')
    mock_open.return_value.__exit__ = mock.Mock()
    mock_json_dump = mock.MagicMock()
    with mock.patch('os.path.exists', return_value=False), \
            mock.patch('builtins.open', mock_open), \
            mock.patch('json.dump', mock_json_dump), \
            mock.patch('mu.logic.DATA_DIR', 'fake_path'), \
            mock.patch('mu.logic.logger', return_value=None) as logger:
        mu.logic.get_admin_file_path('settings.json')
        msg = 'Unable to create admin file: ' \
              'fake_path{}settings.json'.format(os.path.sep)
        logger.error.assert_called_once_with(msg)


def test_get_session_path():
    """
    Ensure the result of calling get_admin_file_path with session.json returns
    the expected result.
    """
    mock_func = mock.MagicMock(return_value='foo')
    with mock.patch('mu.logic.get_admin_file_path', mock_func):
        assert mu.logic.get_session_path() == 'foo'
        mock_func.assert_called_once_with('session.json')


def test_get_settings_path():
    """
    Ensure the result of calling get_admin_file_path with settings.json returns
    the expected result.
    """
    mock_func = mock.MagicMock(return_value='foo')
    with mock.patch('mu.logic.get_admin_file_path', mock_func):
        assert mu.logic.get_settings_path() == 'foo'
        mock_func.assert_called_once_with('settings.json')


def test_extract_envars():
    """
    Given a correct textual representation, get the expected list
    representation of user defined environment variables.
    """
    raw = "FOO=BAR\n BAZ = Q=X    \n\n\n"
    expected = mu.logic.extract_envars(raw)
    assert expected == [
        ['FOO', 'BAR'],
        ['BAZ', 'Q=X'],
    ]


def test_check_flake():
    """
    Ensure the check_flake method calls PyFlakes with the expected code
    reporter.
    """
    mock_r = mock.MagicMock()
    mock_r.log = [{'line_no': 2, 'column': 0, 'message': 'b'}]
    with mock.patch('mu.logic.MuFlakeCodeReporter', return_value=mock_r), \
            mock.patch('mu.logic.check', return_value=None) as mock_check:
        result = mu.logic.check_flake('foo.py', 'some code')
        assert result == {2: mock_r.log}
        mock_check.assert_called_once_with('some code', 'foo.py', mock_r)


def test_check_flake_needing_expansion():
    """
    Ensure the check_flake method calls PyFlakes with the expected code
    reporter.
    """
    mock_r = mock.MagicMock()
    msg = "'microbit.foo' imported but unused"
    mock_r.log = [{'line_no': 2, 'column': 0, 'message': msg}]
    with mock.patch('mu.logic.MuFlakeCodeReporter', return_value=mock_r), \
            mock.patch('mu.logic.check', return_value=None) as mock_check:
        code = 'from microbit import *'
        result = mu.logic.check_flake('foo.py', code)
        assert result == {}
        mock_check.assert_called_once_with(mu.logic.EXPANDED_IMPORT, 'foo.py',
                                           mock_r)


def test_check_flake_with_builtins():
    """
    If a list of assumed builtin symbols is passed, any "undefined name"
    messages for them are ignored.
    """
    mock_r = mock.MagicMock()
    mock_r.log = [{'line_no': 2, 'column': 0,
                  'message': "undefined name 'foo'"}]
    with mock.patch('mu.logic.MuFlakeCodeReporter', return_value=mock_r), \
            mock.patch('mu.logic.check', return_value=None) as mock_check:
        result = mu.logic.check_flake('foo.py', 'some code',
                                      builtins=['foo', ])
        assert result == {}
        mock_check.assert_called_once_with('some code', 'foo.py', mock_r)


def test_check_pycodestyle():
    """
    Ensure the expected result if generated from the PEP8 style validator.
    """
    code = "import foo\n\n\n\n\n\ndef bar():\n    pass\n"  # Generate E303
    result = mu.logic.check_pycodestyle(code)
    assert len(result) == 1
    assert result[6][0]['line_no'] == 6
    assert result[6][0]['column'] == 0
    assert ' above this line' in result[6][0]['message']
    assert result[6][0]['code'] == 'E303'


def test_check_pycodestyle_with_non_ascii():
    """
    Ensure pycodestyle can at least see a file with non-ASCII characters
    """
    code = "x='\u2005'\n"
    try:
        mu.logic.check_pycodestyle(code)
    except Exception as exc:
        assert False, "Exception was raised: %s" % exc
    #
    # Doesn't actually matter what pycodestyle returns; we just want to make
    # sure it didn't error out
    #


def test_MuFlakeCodeReporter_init():
    """
    Check state is set up as expected.
    """
    r = mu.logic.MuFlakeCodeReporter()
    assert r.log == []


def test_MuFlakeCodeReporter_unexpected_error():
    """
    Check the reporter handles unexpected errors.
    """
    r = mu.logic.MuFlakeCodeReporter()
    r.unexpectedError('foo.py', 'Nobody expects the Spanish Inquisition!')
    assert len(r.log) == 1
    assert r.log[0]['line_no'] == 0
    assert r.log[0]['filename'] == 'foo.py'
    assert r.log[0]['message'] == 'Nobody expects the Spanish Inquisition!'


def test_MuFlakeCodeReporter_syntax_error():
    """
    Check the reporter handles syntax errors in a humane and kid friendly
    manner.
    """
    msg = ('Syntax error. Python cannot understand this line. Check for '
           'missing characters!')
    r = mu.logic.MuFlakeCodeReporter()
    r.syntaxError('foo.py', 'something incomprehensible to kids', '2', 3,
                  'source')
    assert len(r.log) == 1
    assert r.log[0]['line_no'] == 1
    assert r.log[0]['message'] == msg
    assert r.log[0]['column'] == 2
    assert r.log[0]['source'] == 'source'


def test_MuFlakeCodeReporter_flake_matched():
    """
    Check the reporter handles flake (regular) errors that match the expected
    message structure.
    """
    r = mu.logic.MuFlakeCodeReporter()
    err = "foo.py:4: something went wrong"
    r.flake(err)
    assert len(r.log) == 1
    assert r.log[0]['line_no'] == 3
    assert r.log[0]['column'] == 0
    assert r.log[0]['message'] == 'something went wrong'


def test_MuFlakeCodeReporter_flake_un_matched():
    """
    Check the reporter handles flake errors that do not conform to the expected
    message structure.
    """
    r = mu.logic.MuFlakeCodeReporter()
    err = "something went wrong"
    r.flake(err)
    assert len(r.log) == 1
    assert r.log[0]['line_no'] == 0
    assert r.log[0]['column'] == 0
    assert r.log[0]['message'] == 'something went wrong'


def test_REPL_posix():
    """
    The port is set correctly in a posix environment.
    """
    with mock.patch('os.name', 'posix'):
        r = mu.logic.REPL('ttyACM0')
        assert r.port == '/dev/ttyACM0'


def test_REPL_nt():
    """
    The port is set correctly in an nt (Windows) environment.
    """
    with mock.patch('os.name', 'nt'):
        r = mu.logic.REPL('COM0')
        assert r.port == 'COM0'


def test_REPL_unsupported():
    """
    A NotImplementedError is raised on an unsupported OS.
    """
    with mock.patch('os.name', 'SPARC'):
        with pytest.raises(NotImplementedError):
            mu.logic.REPL('tty0')


def test_editor_init():
    """
    Ensure a new instance is set-up correctly and creates the required folders
    upon first start.
    """
    view = mock.MagicMock()
    # Check the editor attempts to create required directories if they don't
    # already exist.
    with mock.patch('os.path.exists', return_value=False), \
            mock.patch('os.makedirs', return_value=None) as mkd:
        e = mu.logic.Editor(view)
        assert e._view == view
        assert e.theme == 'day'
        assert e.mode == 'python'
        assert e.modes == {}
        assert e.envars == []
        assert e.minify is False
        assert e.microbit_runtime == ''
        assert e.connected_devices == set()
        assert e.find == ''
        assert e.replace == ''
        assert e.global_replace is False
        assert e.selecting_mode is False
        assert mkd.call_count == 1
        assert mkd.call_args_list[0][0][0] == mu.logic.DATA_DIR


def test_editor_setup():
    """
    An editor should have a modes attribute.
    """
    view = mock.MagicMock()
    e = mu.logic.Editor(view)
    mock_mode = mock.MagicMock()
    mock_mode.workspace_dir.return_value = 'foo'
    mock_modes = {
        'python': mock_mode,
    }
    with mock.patch('os.path.exists', return_value=False), \
            mock.patch('os.makedirs', return_value=None) as mkd, \
            mock.patch('shutil.copy') as mock_shutil:
        e.setup(mock_modes)
        assert mkd.call_count == 5
        assert mkd.call_args_list[0][0][0] == 'foo'
        assert mock_shutil.call_count == 3
    assert e.modes == mock_modes
    view.set_usb_checker.assert_called_once_with(1, e.check_usb)


def test_editor_restore_session_existing_runtime():
    """
    A correctly specified session is restored properly.
    """
    mode, theme = "python", "night"
    file_contents = ["", ""]
    ed = mocked_editor(mode)
    with mock.patch('os.path.isfile', return_value=True):
        with generate_session(theme, mode, file_contents,
                              microbit_runtime='/foo', zoom_level=5):
            ed.restore_session()

    assert ed.theme == theme
    assert ed._view.add_tab.call_count == len(file_contents)
    ed._view.set_theme.assert_called_once_with(theme)
    assert ed.envars == [['name', 'value'], ]
    assert ed.minify is False
    assert ed.microbit_runtime == '/foo'
    assert ed._view.zoom_position == 5


def test_editor_restore_session_missing_runtime():
    """
    If the referenced microbit_runtime file doesn't exist, reset to '' so Mu
    uses the built-in runtime.
    """
    mode, theme = "python", "night"
    file_contents = ["", ""]
    ed = mocked_editor(mode)

    with generate_session(theme, mode, file_contents, microbit_runtime='/foo'):
        ed.restore_session()

    assert ed.theme == theme
    assert ed._view.add_tab.call_count == len(file_contents)
    ed._view.set_theme.assert_called_once_with(theme)
    assert ed.envars == [['name', 'value'], ]
    assert ed.minify is False
    assert ed.microbit_runtime == ''  # File does not exist so set to ''


def test_editor_restore_session_missing_files():
    """
    Missing files that were opened tabs in the previous session are safely
    ignored when attempting to restore them.
    """
    fake_session = os.path.join(os.path.dirname(__file__), 'session.json')
    view = mock.MagicMock()
    ed = mu.logic.Editor(view)
    ed._view.add_tab = mock.MagicMock()
    mock_mode = mock.MagicMock()
    mock_mode.workspace_dir.return_value = '/fake/path'
    mock_mode.save_timeout = 5
    ed.modes = {
        'python': mock_mode,
    }
    mock_gettext = mock.MagicMock()
    mock_gettext.return_value = '# Write your code here :-)'
    get_test_session_path = mock.MagicMock()
    get_test_session_path.return_value = fake_session
    with mock.patch('os.path.exists', return_value=True), \
            mock.patch('mu.logic.get_session_path', get_test_session_path):
        ed.restore_session()
    assert ed._view.add_tab.call_count == 0


def test_editor_restore_session_invalid_mode():
    """
    As Mu's modes are added and/or renamed, invalid mode names may need to be
    ignored (this happens regularly when changing versions when developing
    Mu itself).
    """
    valid_mode, invalid_mode = "python", uuid.uuid1().hex
    ed = mocked_editor(valid_mode)
    with generate_session(mode=invalid_mode):
        ed.restore_session()
    ed.select_mode.assert_called_once_with(None)


def test_editor_restore_session_no_session_file():
    """
    If there's no prior session file (such as upon first start) then simply
    start up the editor with an empty untitled tab.
    """
    view = mock.MagicMock()
    view.tab_count = 0
    ed = mu.logic.Editor(view)
    ed._view.add_tab = mock.MagicMock()
    ed.select_mode = mock.MagicMock()
    mock_mode = mock.MagicMock()
    api = ['API specification', ]
    mock_mode.api.return_value = api
    mock_mode.workspace_dir.return_value = '/fake/path'
    mock_mode.save_timeout = 5
    ed.modes = {
        'python': mock_mode,
    }
    mock_gettext = mock.MagicMock()
    mock_gettext.return_value = '# Write your code here :-)'
    with mock.patch('os.path.exists', return_value=False):
        ed.restore_session()
    py = '# Write your code here :-)'.format(
        os.linesep, os.linesep) + mu.logic.NEWLINE
    ed._view.add_tab.assert_called_once_with(None, py, api, mu.logic.NEWLINE)
    ed.select_mode.assert_called_once_with(None)


def test_editor_restore_session_invalid_file():
    """
    A malformed JSON file is correctly detected and app behaves the same as if
    there was no session file.
    """
    view = mock.MagicMock()
    view.tab_count = 0
    ed = mu.logic.Editor(view)
    ed._view.add_tab = mock.MagicMock()
    mock_mode = mock.MagicMock()
    api = ['API specification', ]
    mock_mode.api.return_value = api
    mock_mode.workspace_dir.return_value = '/fake/path'
    mock_mode.save_timeout = 5
    ed.modes = {
        'python': mock_mode,
    }
    mock_open = mock.mock_open(
        read_data='{"paths": ["path/foo.py", "path/bar.py"]}, invalid: 0}')
    mock_gettext = mock.MagicMock()
    mock_gettext.return_value = '# Write your code here :-)'
    with mock.patch('builtins.open', mock_open), \
            mock.patch('os.path.exists', return_value=True):
        ed.restore_session()
    py = '# Write your code here :-)' + mu.logic.NEWLINE
    ed._view.add_tab.assert_called_once_with(None, py, api, mu.logic.NEWLINE)


def test_editor_open_focus_passed_file():
    """
    A file passed in by the OS is opened
    """
    view = mock.MagicMock()
    view.tab_count = 0
    ed = mu.logic.Editor(view)
    mock_mode = mock.MagicMock()
    mock_mode.workspace_dir.return_value = '/fake/path'
    mock_mode.save_timeout = 5
    ed.modes = {
        'python': mock_mode,
    }
    ed._load = mock.MagicMock()
    file_path = os.path.join(
        os.path.dirname(os.path.realpath(__file__)),
        'scripts',
        'contains_red.py'
    )
    ed.select_mode = mock.MagicMock()
    with mock.patch("builtins.open", mock.mock_open(read_data="data")):
        ed.restore_session([file_path])
        ed._load.assert_called_once_with(file_path)


def test_editor_session_and_open_focus_passed_file():
    """
    A passed in file is merged with session, opened last
    so it receives focus
    It will be the middle position in the session
    """
    view = mock.MagicMock()
    ed = mu.logic.Editor(view)
    ed.modes = mock.MagicMock()
    ed.direct_load = mock.MagicMock()
    mock_mode = mock.MagicMock()
    mock_mode.workspace_dir.return_value = '/fake/path'
    mock_mode.save_timeout = 5
    ed.modes = {
        'python': mock_mode,
    }
    ed.select_mode = mock.MagicMock()
    settings = json.dumps({
        "paths": ["path/foo.py",
                  "path/bar.py"]}, )
    mock_open = mock.mock_open(read_data=settings)
    with mock.patch('builtins.open', mock_open), \
            mock.patch('os.path.exists', return_value=True):
        ed.restore_session(paths=['path/foo.py'])

    # direct_load should be called twice (once for each path)
    assert ed.direct_load.call_count == 2
    # However, "foo.py" as the passed_filename should be direct_load-ed
    # at the end so it has focus, despite being the first file listed in
    # the restored session.
    assert ed.direct_load.call_args_list[0][0][0] == os.path.abspath(
        'path/bar.py')
    assert ed.direct_load.call_args_list[1][0][0] == os.path.abspath(
        'path/foo.py')


def test_toggle_theme_to_night():
    """
    The current theme is 'day' so toggle to night. Expect the state to be
    updated and the appropriate call to the UI layer is made.
    """
    view = mock.MagicMock()
    view.set_theme = mock.MagicMock()
    ed = mu.logic.Editor(view)
    ed.theme = 'day'
    ed.toggle_theme()
    assert ed.theme == 'night'
    view.set_theme.assert_called_once_with(ed.theme)


def test_toggle_theme_to_day():
    """
    The current theme is 'contrast' so toggle to day. Expect the state to be
    updated and the appropriate call to the UI layer is made.
    """
    view = mock.MagicMock()
    view.set_theme = mock.MagicMock()
    ed = mu.logic.Editor(view)
    ed.theme = 'contrast'
    ed.toggle_theme()
    assert ed.theme == 'day'
    view.set_theme.assert_called_once_with(ed.theme)


def test_toggle_theme_to_contrast():
    """
    The current theme is 'night' so toggle to contrast. Expect the state to be
    updated and the appropriate call to the UI layer is made.
    """
    view = mock.MagicMock()
    view.set_theme = mock.MagicMock()
    ed = mu.logic.Editor(view)
    ed.theme = 'night'
    ed.toggle_theme()
    assert ed.theme == 'contrast'
    view.set_theme.assert_called_once_with(ed.theme)


def test_new():
    """
    Ensure an untitled tab is added to the UI.
    """
    view = mock.MagicMock()
    view.add_tab = mock.MagicMock()
    mock_mode = mock.MagicMock()
    api = ['API specification', ]
    mock_mode.api.return_value = api
    ed = mu.logic.Editor(view)
    ed.modes = {
        'python': mock_mode,
    }
    ed.new()
    view.add_tab.assert_called_once_with(None, '', api, mu.logic.NEWLINE)


def test_load_checks_file_exists():
    """
    If the passed in path does not exist, this is logged and no other side
    effect happens.
    """
    view = mock.MagicMock()
    ed = mu.logic.Editor(view)
    with mock.patch('os.path.isfile', return_value=False), \
            mock.patch('mu.logic.logger.info') as mock_info:
        ed._load('not_a_file')
        msg1 = 'Loading script from: not_a_file'
        msg2 = 'The file not_a_file does not exist.'
        assert mock_info.call_args_list[0][0][0] == msg1
        assert mock_info.call_args_list[1][0][0] == msg2


def test_load_python_file():
    """
    If the user specifies a Python file (*.py) then ensure it's loaded and
    added as a tab.
    """
    text, newline = "python", "\n"
    ed = mocked_editor()
    with generate_python_file(text) as filepath:
        ed._view.get_load_path.return_value = filepath
        with mock.patch("mu.logic.read_and_decode") as mock_read:
            mock_read.return_value = text, newline
            ed.load()

    mock_read.assert_called_once_with(filepath)
    ed._view.add_tab.assert_called_once_with(
        filepath,
        text,
        ed.modes[ed.mode].api(),
        newline)


def test_load_python_file_case_insensitive_file_type():
    """
    If the user specifies a Python file (*.PY) then ensure it's loaded and
    added as a tab.
    """
    text, newline = "python", "\n"
    ed = mocked_editor()
    with generate_python_file(text) as filepath:
        ed._view.get_load_path.return_value = filepath.upper()
        with mock.patch("mu.logic.read_and_decode") as mock_read, \
                mock.patch('os.path.isfile', return_value=True):
            mock_read.return_value = text, newline
            ed.load()

    mock_read.assert_called_once_with(filepath.upper())
    ed._view.add_tab.assert_called_once_with(
        filepath.upper(),
        text,
        ed.modes[ed.mode].api(),
        newline)


def test_load_python_unicode_error():
    """
    If Mu encounters a UnicodeDecodeError when trying to read and decode the
    file, it should display a helpful message explaining the problem.
    """
    text = "not utf encoded content"
    ed = mocked_editor()
    with generate_python_file(text) as filepath:
        ed._view.get_load_path.return_value = filepath
        with mock.patch("mu.logic.read_and_decode") as mock_read:
            mock_read.side_effect = UnicodeDecodeError('funnycodec',
                                                       b'\x00\x00', 1, 2,
                                                       'A fake reason!')
            ed.load()
    assert ed._view.show_message.call_count == 1


def test_no_duplicate_load_python_file():
    """
    If the user specifies a file already loaded, ensure this is detected.
    """
    brown_script = os.path.join(
        os.path.dirname(os.path.realpath(__file__)),
        'scripts',
        'contains_brown.py'
    )

    editor_window = mock.MagicMock()
    editor_window.show_message = mock.MagicMock()
    editor_window.focus_tab = mock.MagicMock()
    editor_window.add_tab = mock.MagicMock()

    brown_tab = mock.MagicMock()
    brown_tab.path = brown_script
    unsaved_tab = mock.MagicMock()
    unsaved_tab.path = None

    editor_window.widgets = [unsaved_tab, brown_tab]

    editor_window.get_load_path = mock.MagicMock(return_value=brown_script)
    editor_window.current_tab.path = 'path'
    # Create the "editor" that'll control the "window".
    editor = mu.logic.Editor(view=editor_window)
    mock_mode = mock.MagicMock()
    mock_mode.workspace_dir.return_value = '/fake/path'
    editor.modes = {
        'python': mock_mode,
    }
    editor.load()
    message = 'The file "{}" is already open.'.format(os.path.basename(
                                                      brown_script))
    editor_window.show_message.assert_called_once_with(message)
    editor_window.add_tab.assert_not_called()


def test_load_other_file():
    """
    If the user specifies a file supported by a Mu mode (like a .hex file) then
    ensure it's loaded and added as a tab.
    """
    view = mock.MagicMock()
    view.get_load_path = mock.MagicMock(return_value='foo.hex')
    view.add_tab = mock.MagicMock()
    view.show_confirmation = mock.MagicMock()
    view.current_tab.path = 'path'
    ed = mu.logic.Editor(view)
    ed.change_mode = mock.MagicMock()
    api = ['API specification', ]
    file_content = 'PYTHON CODE'
    mock_py = mock.MagicMock()
    mock_py.open_file.return_value = None
    mock_mb = mock.MagicMock()
    mock_mb.api.return_value = api
    mock_mb.workspace_dir.return_value = '/fake/path'
    mock_mb.open_file.return_value = file_content
    mock_mb.file_extensions = ['hex']
    ed.modes = {
        'python': mock_py,
        'microbit': mock_mb,
    }
    ed.mode = 'microbit'
    with mock.patch('builtins.open', mock.mock_open()), \
            mock.patch('os.path.isfile', return_value=True):
        ed.load()
    assert view.get_load_path.call_count == 1
    assert view.show_confirmation.call_count == 0
    assert ed.change_mode.call_count == 0
    view.add_tab.assert_called_once_with(None, file_content, api, os.linesep)


def test_load_other_file_change_mode():
    """
    If the user specifies a file supported by a Mu mode (like a .hex file) that
    is not currently active, then ensure it's loaded, added as a tab, and it
    asks the user to change mode.
    """
    view = mock.MagicMock()
    view.get_load_path = mock.MagicMock(return_value='foo.hex')
    view.add_tab = mock.MagicMock()
    view.show_confirmation = mock.MagicMock(return_value=QMessageBox.Ok)
    view.current_tab.path = 'path'
    ed = mu.logic.Editor(view)
    ed.change_mode = mock.MagicMock()
    api = ['API specification', ]
    file_content = 'PYTHON CODE'
    mock_py = mock.MagicMock()
    mock_py.open_file.return_value = None
    mock_py.api.return_value = api
    mock_py.workspace_dir.return_value = '/fake/path'
    mock_mb = mock.MagicMock()
    mock_mb.api.return_value = api
    mock_mb.workspace_dir.return_value = '/fake/path'
    mock_mb.open_file.return_value = file_content
    mock_mb.file_extensions = ['hex']
    ed.modes = {
        'python': mock_py,
        'microbit': mock_mb,
    }
    ed.mode = 'python'
    with mock.patch('builtins.open', mock.mock_open()), \
            mock.patch('os.path.isfile', return_value=True):
        ed.load()
    assert view.get_load_path.call_count == 1
    assert view.show_confirmation.call_count == 1
    assert ed.change_mode.call_count == 1
    view.add_tab.assert_called_once_with(None, file_content, api, os.linesep)


def test_load_other_file_with_exception():
    """
    If the user specifies a file supported by a Mu mode (like a .hex file) try
    to open it and check it ignores it if it throws an unexpected exception.
    """
    view = mock.MagicMock()
    view.get_load_path = mock.MagicMock(return_value='foo.hex')
    view.add_tab = mock.MagicMock()
    view.show_confirmation = mock.MagicMock()
    view.current_tab.path = 'path'
    ed = mu.logic.Editor(view)
    ed.change_mode = mock.MagicMock()
    mock_mb = mock.MagicMock()
    mock_mb.workspace_dir.return_value = '/fake/path'
    mock_mb.open_file = mock.MagicMock(side_effect=Exception(':('))
    mock_mb.file_extensions = ['hex']
    ed.modes = {
        'microbit': mock_mb,
    }
    ed.mode = 'microbit'
    mock_open = mock.mock_open()
    with mock.patch('builtins.open', mock_open), \
            mock.patch('os.path.isfile', return_value=True):
        ed.load()
    assert view.get_load_path.call_count == 1
    assert view.show_message.call_count == 1
    assert view.show_confirmation.call_count == 0
    assert ed.change_mode.call_count == 0
    assert view.add_tab.call_count == 0


def test_load_not_python_or_hex():
    """
    If the user tries to open a file that isn't .py or .hex then Mu should
    report a helpful message.
    """
    view = mock.MagicMock()
    ed = mu.logic.Editor(view)
    with mock.patch('os.path.isfile', return_value=True):
        ed._load('unknown_filetype.foo')
    assert view.show_message.call_count == 1


def test_load_recovers_from_oserror():
    """
    If loading the file results in an OSError (for example, the user doesn't
    have permission to read the file), then a helpful message is displayed.
    """
    text = "python"
    ed = mocked_editor()
    with generate_python_file(text) as filepath, \
            mock.patch('mu.logic.read_and_decode',
                       side_effect=OSError('boom')):
        ed._view.get_load_path.return_value = filepath
        ed.load()
    assert ed._view.show_message.call_count == 1


#
# When loading files Mu makes a note of the majority line-ending convention
# in use in the file. When it is saved, that convention is used.
#
def test_load_stores_newline():
    """
    When a file is loaded, its newline convention should be held on the tab
    for use when saving.
    """
    newline = "r\n"
    text = newline.join("the cat sat on the mat".split())
    editor = mocked_editor()
    with generate_python_file("abc\r\ndef") as filepath:
        editor._view.get_load_path.return_value = filepath
        editor.load()

    assert editor._view.add_tab.called_with(
        filepath, text, editor.modes[editor.mode].api(), "\r\n")


def test_save_restores_newline():
    """
    When a file is saved the newline convention noted originally should
    be used.
    """
    newline = "\r\n"
    test_text = mu.logic.NEWLINE.join(
        "the cat sat on the mat".split()
    )
    with generate_python_file(test_text) as filepath:
        with mock.patch("mu.logic.save_and_encode") as mock_save:
            ed = mocked_editor(text=test_text, newline=newline, path=filepath)
            ed.save()
            assert mock_save.called_with(test_text, filepath, newline)


def test_save_strips_trailing_spaces():
    """
    When a file is saved any trailing spaces should be removed from each line
    leaving any newlines intact. NB we inadvertently strip trailing newlines
    in any case via save_and_encode
    """
    words = "the cat sat on the mat".split()
    test_text = mu.logic.NEWLINE.join("%s " % w for w in words)
    stripped_text = mu.logic.NEWLINE.join(words)
    with generate_python_file(test_text) as filepath:
        mu.logic.save_and_encode(test_text, filepath)
        with open(filepath) as f:
            assert f.read() == stripped_text


def test_load_error():
    """
    Ensure that anything else is just ignored.
    """
    view = mock.MagicMock()
    view.get_load_path = mock.MagicMock(return_value='foo.py')
    view.add_tab = mock.MagicMock()
    view.current_tab.path = 'path'
    ed = mu.logic.Editor(view)
    mock_open = mock.MagicMock(side_effect=FileNotFoundError())
    mock_mode = mock.MagicMock()
    mock_mode.workspace_dir.return_value = '/fake/path'
    ed.modes = {
        'python': mock_mode,
    }
    with mock.patch('builtins.open', mock_open):
        ed.load()
    assert view.get_load_path.call_count == 1
    assert view.add_tab.call_count == 0


def test_load_sets_current_path():
    """
    When a path has been selected for loading by the OS's file selector,
    ensure that the directory containing the selected file is set as the
    self.current_path for re-use later on.
    """
    view = mock.MagicMock()
    view.get_load_path = mock.MagicMock(return_value=os.path.join('path',
                                                                  'foo.py'))
    view.current_tab.path = os.path.join('old_path', 'foo.py')
    ed = mu.logic.Editor(view)
    ed._load = mock.MagicMock()
    mock_mode = mock.MagicMock()
    mock_mode.workspace_dir.return_value = '/fake/path'
    mock_mode.file_extensions = ['html', 'css']
    ed.modes = {
        'python': mock_mode,
    }
    ed.load()
    assert ed.current_path == os.path.abspath('path')


def test_load_no_current_path():
    """
    If there is no self.current_path the default location to look for a file
    to load is the directory containing the file currently being edited.
    """
    view = mock.MagicMock()
    view.get_load_path = mock.MagicMock(return_value=os.path.join('path',
                                                                  'foo.py'))
    view.current_tab.path = os.path.join('old_path', 'foo.py')
    ed = mu.logic.Editor(view)
    ed._load = mock.MagicMock()
    mock_mode = mock.MagicMock()
    mock_mode.workspace_dir.return_value = '/fake/path'
    mock_mode.file_extensions = []
    ed.modes = {
        'python': mock_mode,
    }
    ed.load()
    expected = os.path.abspath('old_path')
    view.get_load_path.assert_called_once_with(expected, '*.py *.PY')


def test_load_no_current_path_no_current_tab():
    """
    If there is no self.current_path nor is there a current file being edited
    then the default location to look for a file to load is the current
    mode's workspace directory. This used to be the default behaviour, but now
    acts as a sensible fall-back.
    """
    view = mock.MagicMock()
    view.get_load_path = mock.MagicMock(return_value=os.path.join('path',
                                                                  'foo.py'))
    view.current_tab = None
    ed = mu.logic.Editor(view)
    ed._load = mock.MagicMock()
    mock_mode = mock.MagicMock()
    mock_mode.workspace_dir.return_value = os.path.join('fake', 'path')
    mock_mode.file_extensions = []
    ed.modes = {
        'python': mock_mode,
    }
    ed.load()
    expected = mock_mode.workspace_dir()
    view.get_load_path.assert_called_once_with(expected, '*.py *.PY')


def test_load_has_current_path_does_not_exist():
    """
    If there is a self.current_path but it doesn't exist, then use the expected
    fallback as the location to look for a file to load.
    """
    view = mock.MagicMock()
    view.get_load_path = mock.MagicMock(return_value=os.path.join('path',
                                                                  'foo.py'))
    view.current_tab = None
    ed = mu.logic.Editor(view)
    ed._load = mock.MagicMock()
    ed.current_path = 'foo'
    mock_mode = mock.MagicMock()
    mock_mode.workspace_dir.return_value = os.path.join('fake', 'path')
    mock_mode.file_extensions = []
    ed.modes = {
        'python': mock_mode,
    }
    ed.load()
    expected = mock_mode.workspace_dir()
    view.get_load_path.assert_called_once_with(expected, '*.py *.PY')


def test_load_has_current_path():
    """
    If there is a self.current_path then use this as the location to look for
    a file to load.
    """
    view = mock.MagicMock()
    view.get_load_path = mock.MagicMock(return_value=os.path.join('path',
                                                                  'foo.py'))
    view.current_tab = None
    ed = mu.logic.Editor(view)
    ed._load = mock.MagicMock()
    ed.current_path = 'foo'
    mock_mode = mock.MagicMock()
    mock_mode.workspace_dir.return_value = os.path.join('fake', 'path')
    mock_mode.file_extensions = []
    ed.modes = {
        'python': mock_mode,
    }
    with mock.patch('os.path.isdir', return_value=True):
        ed.load()
    view.get_load_path.assert_called_once_with('foo', '*.py *.PY')


def test_check_for_shadow_module_with_match():
    """
    If the name of the file in the path passed into check_for_shadow_module
    (without the .py file extension) is found in module_names then return
    True since the filename shadows that of a module found on the Python path.
    """
    view = mock.MagicMock()
    ed = mu.logic.Editor(view)
    mock_mode = mock.MagicMock()
    mock_mode.module_names = set(['foo', 'bar', 'baz'])
    ed.modes = {
        'python': mock_mode,
    }
    ed.mode = 'python'
    assert ed.check_for_shadow_module('/a/long/path/with/foo.py')


def test_save_no_tab():
    """
    If there's no active tab then do nothing.
    """
    view = mock.MagicMock()
    view.current_tab = None
    ed = mu.logic.Editor(view)
    ed.save()
    # If the code fell through then the tab state would be modified.
    assert view.current_tab is None


def test_save_no_path():
    """
    If there's no path associated with the tab then request the user provide
    one.
    """
    text, path, newline = "foo", "foo.py", "\n"
    ed = mocked_editor(text=text, path=None, newline=newline)
    ed._view.get_save_path.return_value = path
    ed.check_for_shadow_module = mock.MagicMock(return_value=False)
    with mock.patch("mu.logic.save_and_encode") as mock_save:
        ed.save()
    mock_save.assert_called_with(text, path, newline)


def test_save_no_path_no_path_given():
    """
    If there's no path associated with the tab and the user cancels providing
    one, ensure the path is correctly re-set.
    """
    text, newline = "foo", "\n"
    ed = mocked_editor(text=text, path=None, newline=newline)
    ed._view.get_save_path.return_value = ''
    ed.save()
    # The path isn't the empty string returned from get_save_path.
    assert ed._view.current_tab.path is None


def test_save_path_shadows_module():
    """
    If the filename in the path shadows a module then display a warning message
    and abort.
    """
    text, newline = "foo", "\n"
    ed = mocked_editor(text=text, path=None, newline=newline)
    ed._view.get_save_path.return_value = '/a/long/path/foo.py'
    mock_mode = mock.MagicMock()
    mock_mode.module_names = set(['foo', 'bar', 'baz'])
    ed.modes = {
        'python': mock_mode,
    }
    ed.mode = 'python'
    ed.save()
    # The path isn't the empty string returned from get_save_path.
    assert ed._view.show_message.call_count == 1
    assert ed._view.current_tab.path is None


def test_save_file_with_exception():
    """
    If the file cannot be written, return an error message.
    """
    view = mock.MagicMock()
    view.current_tab = mock.MagicMock()
    view.current_tab.path = 'foo.py'
    view.current_tab.text = mock.MagicMock(return_value='foo')
    view.current_tab.setModified = mock.MagicMock(return_value=None)
    view.show_message = mock.MagicMock()
    mock_open = mock.MagicMock(side_effect=OSError())
    ed = mu.logic.Editor(view)
    with mock.patch('builtins.open', mock_open):
        ed.save()
    assert view.current_tab.setModified.call_count == 0
    assert view.show_message.call_count == 1


def test_save_file_with_encoding_error():
    """
    If Mu encounters a UnicodeEncodeError when trying to write the file,
    it should display a helpful message explaining the problem.
    """
    text, path, newline = "foo", "foo", "\n"
    ed = mocked_editor(text=text, path=path, newline=newline)
    with mock.patch("mu.logic.save_and_encode") as mock_save:
        mock_save.side_effect = UnicodeEncodeError(mu.logic.ENCODING, "",
                                                   0, 0, "Unable to encode")
        ed.save()

    assert ed._view.current_tab.setModified.call_count == 0


def test_save_python_file():
    """
    If the path is a Python file (ending in *.py) then save it and reset the
    modified flag.
    """
    path, contents, newline = "foo.py", "foo", "\n"
    view = mock.MagicMock()
    view.current_tab = mock.MagicMock()
    view.current_tab.path = path
    view.current_tab.text = mock.MagicMock(return_value=contents)
    view.current_tab.newline = "\n"
    view.get_save_path = mock.MagicMock(return_value=path)
    view.current_tab.setModified = mock.MagicMock(return_value=None)
    ed = mu.logic.Editor(view)
    with mock.patch("mu.logic.save_and_encode") as mock_save:
        ed.save()

    mock_save.assert_called_once_with(contents, path, newline)
    assert view.get_save_path.call_count == 0
    view.current_tab.setModified.assert_called_once_with(False)


def test_save_with_no_file_extension():
    """
    If the path doesn't end in *.py then append it to the filename.
    """
    text, path, newline = "foo", "foo", "\n"
    ed = mocked_editor(text=text, path=path, newline=newline)
    with mock.patch('mu.logic.save_and_encode') as mock_save:
        ed.save()
    mock_save.assert_called_once_with(text, path + ".py", newline)
    ed._view.get_save_path.call_count == 0


def test_save_with_non_py_file_extension():
    """
    If the path ends in an extension, save it using the extension
    """
    text, path, newline = "foo", "foo.txt", "\n"
    ed = mocked_editor(text=text, path=path, newline=newline)
    ed._view.get_save_path.return_value = path
    with mock.patch('mu.logic.save_and_encode') as mock_save:
        ed.save()
    mock_save.assert_called_once_with(text, path, newline)
    ed._view.get_save_path.call_count == 0


def test_get_tab_existing_tab():
    """
    Ensure that an existing tab is returned if its path matches.
    """
    view = mock.MagicMock()
    mock_tab = mock.MagicMock()
    mock_tab.path = 'foo'
    view.widgets = [mock_tab, ]
    ed = mu.logic.Editor(view)
    view.focus_tab.reset_mock()
    tab = ed.get_tab('foo')
    assert tab == mock_tab
    view.focus_tab.assert_called_once_with(mock_tab)


def test_get_tab_new_tab():
    """
    If the path is not represented by an existing tab, ensure it is loaded and
    the new tab is returned.
    """
    view = mock.MagicMock()
    mock_tab = mock.MagicMock()
    mock_tab.path = 'foo'
    view.widgets = [mock_tab, ]
    ed = mu.logic.Editor(view)
    ed.direct_load = mock.MagicMock()
    tab = ed.get_tab('bar')
    ed.direct_load.assert_called_once_with('bar')
    assert tab == view.current_tab


def test_get_tab_no_path():
    """
    Any tabs with no associated path are ignored (i.e. tabs that have been
    newly created but remain unsaved).
    """
    view = mock.MagicMock()
    mock_tab = mock.MagicMock()
    mock_tab.path = None
    view.widgets = [mock_tab, ]
    ed = mu.logic.Editor(view)
    ed.direct_load = mock.MagicMock()
    tab = ed.get_tab('bar')
    ed.direct_load.assert_called_once_with('bar')
    assert tab == view.current_tab


def test_zoom_in():
    """
    Ensure the UI layer is zoomed in.
    """
    view = mock.MagicMock()
    view.zoom_in = mock.MagicMock(return_value=None)
    ed = mu.logic.Editor(view)
    ed.zoom_in()
    assert view.zoom_in.call_count == 1


def test_zoom_out():
    """
    Ensure the UI layer is zoomed out.
    """
    view = mock.MagicMock()
    view.zoom_out = mock.MagicMock(return_value=None)
    ed = mu.logic.Editor(view)
    ed.zoom_out()
    assert view.zoom_out.call_count == 1


def test_check_code_on():
    """
    Checking code correctly results in something the UI layer can parse.
    """
    view = mock.MagicMock()
    tab = mock.MagicMock()
    tab.has_annotations = False
    tab.path = 'foo.py'
    tab.text.return_value = 'import this\n'
    view.current_tab = tab
    flake = {2: {'line_no': 2, 'message': 'a message', }, }
    pep8 = {2: [{'line_no': 2, 'message': 'another message', }],
            3: [{'line_no': 3, 'message': 'yet another message', }]}
    mock_mode = mock.MagicMock()
    mock_mode.builtins = None
    with mock.patch('mu.logic.check_flake', return_value=flake), \
            mock.patch('mu.logic.check_pycodestyle', return_value=pep8):
        ed = mu.logic.Editor(view)
        ed.modes = {'python': mock_mode, }
        ed.check_code()
        assert tab.has_annotations is True
        view.reset_annotations.assert_called_once_with()
        view.annotate_code.assert_has_calls([mock.call(flake, 'error'),
                                             mock.call(pep8, 'style')],
                                            any_order=True)


def test_check_code_no_problems():
    """
    If no problems are found in the code, ensure a status message is shown to
    the user to confirm the fact. See #337
    """
    view = mock.MagicMock()
    tab = mock.MagicMock()
    tab.has_annotations = False
    tab.path = 'foo.py'
    tab.text.return_value = 'import this\n'
    view.current_tab = tab
    flake = {}
    pep8 = {}
    mock_mode = mock.MagicMock()
    mock_mode.builtins = None
    with mock.patch('mu.logic.check_flake', return_value=flake), \
            mock.patch('mu.logic.check_pycodestyle', return_value=pep8):
        ed = mu.logic.Editor(view)
        ed.show_status_message = mock.MagicMock()
        ed.modes = {'python': mock_mode, }
        ed.check_code()
        assert ed.show_status_message.call_count == 1


def test_check_code_off():
    """
    If the tab already has annotations, toggle them off.
    """
    view = mock.MagicMock()
    tab = mock.MagicMock()
    tab.has_annotations = True
    view.current_tab = tab
    ed = mu.logic.Editor(view)
    ed.check_code()
    assert tab.has_annotations is False
    view.reset_annotations.assert_called_once_with()


def test_check_code_no_tab():
    """
    Checking code when there is no tab containing code aborts the process.
    """
    view = mock.MagicMock()
    view.current_tab = None
    ed = mu.logic.Editor(view)
    ed.check_code()
    assert view.annotate_code.call_count == 0


def test_show_help():
    """
    Help should attempt to open up the user's browser and point it to the
    expected help documentation.
    """
    view = mock.MagicMock()
    ed = mu.logic.Editor(view)
    with mock.patch('mu.logic.webbrowser.open_new', return_value=None) as wb, \
            mock.patch('mu.logic.locale.getdefaultlocale',
                       return_value=('en_GB', 'UTF-8')):
        ed.show_help()
        version = '.'.join(__version__.split('.')[:2])
        url = 'https://codewith.mu/en/help/{}'.format(version)
        wb.assert_called_once_with(url)


def test_show_help_exploding_getdefaultlocale():
    """
    Sometimes, on OSX the getdefaultlocale method causes a TypeError or
    ValueError. Ensure when this happens, Mu defaults to 'en' as the language
    code.
    """
    view = mock.MagicMock()
    ed = mu.logic.Editor(view)
    with mock.patch('mu.logic.webbrowser.open_new', return_value=None) as wb, \
            mock.patch('mu.logic.locale.getdefaultlocale',
                       side_effect=TypeError('Boom!')):
        ed.show_help()
        version = '.'.join(__version__.split('.')[:2])
        url = 'https://codewith.mu/en/help/{}'.format(version)
        wb.assert_called_once_with(url)


def test_quit_modified_cancelled_from_button():
    """
    If the user quits and there's unsaved work, and they cancel the "quit" then
    do nothing.
    """
    view = mock.MagicMock()
    view.modified = True
    view.show_confirmation = mock.MagicMock(return_value=QMessageBox.Cancel)
    ed = mu.logic.Editor(view)
    mock_open = mock.MagicMock()
    mock_open.return_value.__enter__ = lambda s: s
    mock_open.return_value.__exit__ = mock.Mock()
    mock_open.return_value.write = mock.MagicMock()
    with mock.patch('sys.exit', return_value=None), \
            mock.patch('builtins.open', mock_open):
        ed.quit()
    assert view.show_confirmation.call_count == 1
    assert mock_open.call_count == 0


def test_quit_modified_cancelled_from_event():
    """
    If the user quits and there's unsaved work, and they cancel the "quit" then
    do nothing.
    """
    view = mock.MagicMock()
    view.modified = True
    view.show_confirmation = mock.MagicMock(return_value=QMessageBox.Cancel)
    ed = mu.logic.Editor(view)
    mock_open = mock.MagicMock()
    mock_open.return_value.__enter__ = lambda s: s
    mock_open.return_value.__exit__ = mock.Mock()
    mock_open.return_value.write = mock.MagicMock()
    mock_event = mock.MagicMock()
    mock_event.ignore = mock.MagicMock(return_value=None)
    with mock.patch('sys.exit', return_value=None), \
            mock.patch('builtins.open', mock_open):
        ed.quit(mock_event)
    assert view.show_confirmation.call_count == 1
    assert mock_event.ignore.call_count == 1
    assert mock_open.call_count == 0


def test_quit_modified_ok():
    """
    If the user quits and there's unsaved work that's ignored then proceed to
    save the session.
    """
    view = mock.MagicMock()
    view.modified = True
    view.show_confirmation = mock.MagicMock(return_value=True)
    ed = mu.logic.Editor(view)
    mock_mode = mock.MagicMock()
    mock_mode.workspace_dir.return_value = 'foo/bar'
    mock_mode.get_hex_path.return_value = 'foo/bar'
    mock_debug_mode = mock.MagicMock()
    mock_debug_mode.is_debugger = True
    ed.modes = {
        'python': mock_mode,
        'microbit': mock_mode,
        'debugger': mock_debug_mode,
    }
    ed.mode = 'debugger'
    mock_open = mock.MagicMock()
    mock_open.return_value.__enter__ = lambda s: s
    mock_open.return_value.__exit__ = mock.Mock()
    mock_open.return_value.write = mock.MagicMock()
    mock_event = mock.MagicMock()
    mock_event.ignore = mock.MagicMock(return_value=None)
    with mock.patch('sys.exit', return_value=None), \
            mock.patch('builtins.open', mock_open):
        ed.quit(mock_event)
    mock_debug_mode.stop.assert_called_once_with()
    assert view.show_confirmation.call_count == 1
    assert mock_event.ignore.call_count == 0
    assert mock_open.call_count == 1
    assert mock_open.return_value.write.call_count > 0


def test_quit_save_tabs_with_paths():
    """
    When saving the session, ensure those tabs with associated paths are
    logged in the session file.
    """
    view = mock.MagicMock()
    view.modified = True
    view.zoom_position = 2
    view.show_confirmation = mock.MagicMock(return_value=True)
    w1 = mock.MagicMock()
    w1.path = 'foo.py'
    view.widgets = [w1, ]
    ed = mu.logic.Editor(view)
    mock_mode = mock.MagicMock()
    mock_mode.workspace_dir.return_value = 'foo/bar'
    mock_mode.get_hex_path.return_value = 'foo/bar'
    ed.modes = {
        'python': mock_mode,
        'microbit': mock_mode,
    }
    mock_open = mock.MagicMock()
    mock_open.return_value.__enter__ = lambda s: s
    mock_open.return_value.__exit__ = mock.Mock()
    mock_open.return_value.write = mock.MagicMock()
    mock_event = mock.MagicMock()
    mock_event.ignore = mock.MagicMock(return_value=None)
    with mock.patch('sys.exit', return_value=None), \
            mock.patch('builtins.open', mock_open):
        ed.quit(mock_event)
    assert view.show_confirmation.call_count == 1
    assert mock_event.ignore.call_count == 0
    assert mock_open.call_count == 1
    assert mock_open.return_value.write.call_count > 0
    recovered = ''.join([i[0][0] for i
                        in mock_open.return_value.write.call_args_list])
    session = json.loads(recovered)
    assert os.path.abspath('foo.py') in session['paths']


def test_quit_save_theme():
    """
    When saving the session, ensure the theme is logged in the session file.
    """
    view = mock.MagicMock()
    view.modified = True
    view.zoom_position = 2
    view.show_confirmation = mock.MagicMock(return_value=True)
    w1 = mock.MagicMock()
    w1.path = 'foo.py'
    view.widgets = [w1, ]
    ed = mu.logic.Editor(view)
    ed.theme = 'night'
    mock_mode = mock.MagicMock()
    mock_mode.workspace_dir.return_value = 'foo/bar'
    mock_mode.get_hex_path.return_value = 'foo/bar'
    ed.modes = {
        'python': mock_mode,
        'microbit': mock_mode,
    }
    mock_open = mock.MagicMock()
    mock_open.return_value.__enter__ = lambda s: s
    mock_open.return_value.__exit__ = mock.Mock()
    mock_open.return_value.write = mock.MagicMock()
    mock_event = mock.MagicMock()
    mock_event.ignore = mock.MagicMock(return_value=None)
    with mock.patch('sys.exit', return_value=None), \
            mock.patch('builtins.open', mock_open):
        ed.quit(mock_event)
    assert view.show_confirmation.call_count == 1
    assert mock_event.ignore.call_count == 0
    assert mock_open.call_count == 1
    assert mock_open.return_value.write.call_count > 0
    recovered = ''.join([i[0][0] for i
                        in mock_open.return_value.write.call_args_list])
    session = json.loads(recovered)
    assert session['theme'] == 'night'


def test_quit_save_envars():
    """
    When saving the session, ensure the user defined envars are logged in the
    session file.
    """
    view = mock.MagicMock()
    view.modified = True
    view.zoom_position = 2
    view.show_confirmation = mock.MagicMock(return_value=True)
    w1 = mock.MagicMock()
    w1.path = 'foo.py'
    view.widgets = [w1, ]
    ed = mu.logic.Editor(view)
    ed.theme = 'night'
    mock_mode = mock.MagicMock()
    mock_mode.workspace_dir.return_value = 'foo/bar'
    mock_mode.get_hex_path.return_value = 'foo/bar'
    ed.modes = {
        'python': mock_mode,
        'microbit': mock_mode,
    }
    ed.envars = [
        ['name1', 'value1'],
        ['name2', 'value2'],
    ]
    mock_open = mock.MagicMock()
    mock_open.return_value.__enter__ = lambda s: s
    mock_open.return_value.__exit__ = mock.Mock()
    mock_open.return_value.write = mock.MagicMock()
    mock_event = mock.MagicMock()
    mock_event.ignore = mock.MagicMock(return_value=None)
    with mock.patch('sys.exit', return_value=None), \
            mock.patch('builtins.open', mock_open):
        ed.quit(mock_event)
    assert view.show_confirmation.call_count == 1
    assert mock_event.ignore.call_count == 0
    assert mock_open.call_count == 1
    assert mock_open.return_value.write.call_count > 0
    recovered = ''.join([i[0][0] for i
                        in mock_open.return_value.write.call_args_list])
    session = json.loads(recovered)
    assert session['envars'] == [['name1', 'value1'], ['name2', 'value2'], ]


def test_quit_save_zoom_level():
    """
    When saving the session, ensure the zoom level is logged in the session
    file.
    """
    view = mock.MagicMock()
    view.modified = True
    view.zoom_position = 2
    view.show_confirmation = mock.MagicMock(return_value=True)
    w1 = mock.MagicMock()
    w1.path = 'foo.py'
    view.widgets = [w1, ]
    ed = mu.logic.Editor(view)
    ed.theme = 'night'
    mock_mode = mock.MagicMock()
    mock_mode.workspace_dir.return_value = 'foo/bar'
    mock_mode.get_hex_path.return_value = 'foo/bar'
    ed.modes = {
        'python': mock_mode,
        'microbit': mock_mode,
    }
    ed.envars = [
        ['name1', 'value1'],
        ['name2', 'value2'],
    ]
    mock_open = mock.MagicMock()
    mock_open.return_value.__enter__ = lambda s: s
    mock_open.return_value.__exit__ = mock.Mock()
    mock_open.return_value.write = mock.MagicMock()
    mock_event = mock.MagicMock()
    mock_event.ignore = mock.MagicMock(return_value=None)
    with mock.patch('sys.exit', return_value=None), \
            mock.patch('builtins.open', mock_open):
        ed.quit(mock_event)
    assert view.show_confirmation.call_count == 1
    assert mock_event.ignore.call_count == 0
    assert mock_open.call_count == 1
    assert mock_open.return_value.write.call_count > 0
    recovered = ''.join([i[0][0] for i
                        in mock_open.return_value.write.call_args_list])
    session = json.loads(recovered)
    assert session['zoom_level'] == 2


def test_quit_cleans_temporary_pth_file_on_windows():
    """
    If the platform is Windows and Mu is running as installed by the official
    Windows installer, then check for the existence of mu.pth, and if found,
    delete it.
    """
    view = mock.MagicMock()
    view.modified = True
    view.show_confirmation = mock.MagicMock(return_value=True)
    w1 = mock.MagicMock()
    w1.path = 'foo.py'
    view.widgets = [w1, ]
    ed = mu.logic.Editor(view)
    ed.theme = 'night'
    ed.modes = {
        'python': mock.MagicMock(),
        'microbit': mock.MagicMock(),
    }
    mock_open = mock.MagicMock()
    mock_open.return_value.__enter__ = lambda s: s
    mock_open.return_value.__exit__ = mock.Mock()
    mock_open.return_value.write = mock.MagicMock()
    mock_event = mock.MagicMock()
    mock_event.ignore = mock.MagicMock(return_value=None)
    mock_sys = mock.MagicMock()
    mock_sys.platform = 'win32'
    mock_sys.executable = 'C:\\Program Files\\Mu\\Python\\pythonw.exe'
    mock_os_p_e = mock.MagicMock(return_value=True)
    mock_os_remove = mock.MagicMock()
    mock_site = mock.MagicMock()
    mock_site.ENABLE_USER_SITE = True
    mock_site.USER_SITE = ('C:\\Users\\foo\\AppData\\Roaming\\Python\\'
                           'Python36\\site-packages')
    with mock.patch('sys.exit', return_value=None), \
            mock.patch('builtins.open', mock_open),\
            mock.patch('json.dump'),\
            mock.patch('mu.logic.sys', mock_sys),\
            mock.patch('mu.logic.os.path.exists', mock_os_p_e),\
            mock.patch('mu.logic.os.remove', mock_os_remove),\
            mock.patch('mu.logic.site', mock_site):
        ed.quit(mock_event)
    expected_path = os.path.join(mock_site.USER_SITE, 'mu.pth')
    mock_os_remove.assert_called_once_with(expected_path)


def test_quit_unable_to_clean_temporary_pth_file_on_windows():
    """
    If the platform is Windows and Mu is running as installed by the official
    Windows installer, then check for the existence of mu.pth, and if found,
    attempt to delete it, but in the case of an error, simply log the error
    for future reference / debugging.
    """
    view = mock.MagicMock()
    view.modified = True
    view.show_confirmation = mock.MagicMock(return_value=True)
    w1 = mock.MagicMock()
    w1.path = 'foo.py'
    view.widgets = [w1, ]
    ed = mu.logic.Editor(view)
    ed.theme = 'night'
    ed.modes = {
        'python': mock.MagicMock(),
        'microbit': mock.MagicMock(),
    }
    mock_open = mock.MagicMock()
    mock_open.return_value.__enter__ = lambda s: s
    mock_open.return_value.__exit__ = mock.Mock()
    mock_open.return_value.write = mock.MagicMock()
    mock_event = mock.MagicMock()
    mock_event.ignore = mock.MagicMock(return_value=None)
    mock_sys = mock.MagicMock()
    mock_sys.platform = 'win32'
    mock_sys.executable = 'C:\\Program Files\\Mu\\Python\\pythonw.exe'
    mock_os_p_e = mock.MagicMock(return_value=True)
    mock_os_remove = mock.MagicMock(side_effect=PermissionError('Boom'))
    mock_site = mock.MagicMock()
    mock_site.ENABLE_USER_SITE = True
    mock_site.USER_SITE = ('C:\\Users\\foo\\AppData\\Roaming\\Python\\'
                           'Python36\\site-packages')
    mock_log = mock.MagicMock()
    with mock.patch('sys.exit', return_value=None), \
            mock.patch('builtins.open', mock_open),\
            mock.patch('json.dump'),\
            mock.patch('mu.logic.sys', mock_sys),\
            mock.patch('mu.logic.os.path.exists', mock_os_p_e),\
            mock.patch('mu.logic.os.remove', mock_os_remove),\
            mock.patch('mu.logic.site', mock_site),\
            mock.patch('mu.logic.logger', mock_log):
        ed.quit(mock_event)
    logs = [call[0][0] for call in mock_log.error.call_args_list]
    expected_path = os.path.join(mock_site.USER_SITE, 'mu.pth')
    expected = 'Unable to delete {}'.format(expected_path)
    assert expected in logs


def test_quit_calls_sys_exit():
    """
    Ensure that sys.exit(0) is called.
    """
    view = mock.MagicMock()
    view.modified = True
    view.show_confirmation = mock.MagicMock(return_value=True)
    w1 = mock.MagicMock()
    w1.path = 'foo.py'
    view.widgets = [w1, ]
    ed = mu.logic.Editor(view)
    ed.theme = 'night'
    ed.modes = {
        'python': mock.MagicMock(),
        'microbit': mock.MagicMock(),
    }
    mock_open = mock.MagicMock()
    mock_open.return_value.__enter__ = lambda s: s
    mock_open.return_value.__exit__ = mock.Mock()
    mock_open.return_value.write = mock.MagicMock()
    mock_event = mock.MagicMock()
    mock_event.ignore = mock.MagicMock(return_value=None)
    with mock.patch('sys.exit', return_value=None) as ex, \
            mock.patch('builtins.open', mock_open):
        ed.quit(mock_event)
    ex.assert_called_once_with(0)


def test_show_admin():
    """
    Ensure the expected admin dialog is displayed to the end user.
    """
    view = mock.MagicMock()
    ed = mu.logic.Editor(view)
    ed.envars = [['name', 'value'], ]
    ed.minify = True
    ed.microbit_runtime = '/foo/bar'
    settings = {
        'envars': 'name=value',
        'minify': True,
        'microbit_runtime': '/foo/bar'
    }
    view.show_admin.return_value = settings
    mock_open = mock.mock_open()
    with mock.patch('builtins.open', mock_open), \
            mock.patch('os.path.isfile', return_value=True):
        ed.show_admin(None)
        mock_open.assert_called_once_with(mu.logic.LOG_FILE, 'r',
                                          encoding='utf8')
        assert view.show_admin.call_count == 1
        assert view.show_admin.call_args[0][1] == settings
        assert ed.envars == [['name', 'value']]
        assert ed.minify is True
        assert ed.microbit_runtime == '/foo/bar'


def test_show_admin_missing_microbit_runtime():
    """
    Ensure the microbit_runtime result is '' and a warning message is displayed
    if the specified microbit_runtime doesn't actually exist.
    """
    view = mock.MagicMock()
    ed = mu.logic.Editor(view)
    ed.envars = [['name', 'value'], ]
    ed.minify = True
    ed.microbit_runtime = '/foo/bar'
    settings = {
        'envars': 'name=value',
        'minify': True,
        'microbit_runtime': '/foo/bar'
    }
    view.show_admin.return_value = settings
    mock_open = mock.mock_open()
    with mock.patch('builtins.open', mock_open), \
            mock.patch('os.path.isfile', return_value=False):
        ed.show_admin(None)
        mock_open.assert_called_once_with(mu.logic.LOG_FILE, 'r',
                                          encoding='utf8')
        assert view.show_admin.call_count == 1
        assert view.show_admin.call_args[0][1] == settings
        assert ed.envars == [['name', 'value']]
        assert ed.minify is True
        assert ed.microbit_runtime == ''
        assert view.show_message.call_count == 1


def test_select_mode():
    """
    It's possible to select and update to a new mode.
    """
    view = mock.MagicMock()
    view.select_mode.return_value = 'foo'
    mode = mock.MagicMock()
    mode.is_debugger = False
    ed = mu.logic.Editor(view)
    ed.modes = {
        'python': mode,
    }
    ed.change_mode = mock.MagicMock()
    ed.select_mode(None)
    assert view.select_mode.call_count == 1
    ed.change_mode.assert_called_once_with('foo')


def test_select_mode_debug_mode():
    """
    It's NOT possible to select and update to a new mode if you're in debug
    mode.
    """
    view = mock.MagicMock()
    mode = mock.MagicMock()
    mode.debugger = True
    ed = mu.logic.Editor(view)
    ed.modes = {
        'debugger': mode,
    }
    ed.mode = 'debugger'
    ed.change_mode = mock.MagicMock()
    ed.select_mode(None)
    assert ed.mode == 'debugger'
    assert ed.change_mode.call_count == 0


def test_change_mode():
    """
    It should be possible to change modes in the expected fashion (buttons get
    correctly connected to event handlers).
    """
    view = mock.MagicMock()
    mock_button_bar = mock.MagicMock()
    view.button_bar = mock_button_bar
    view.change_mode = mock.MagicMock()
    ed = mu.logic.Editor(view)
    old_mode = mock.MagicMock()
    old_mode.save_timeout = 5
    old_mode.actions.return_value = [
        {
            'name': 'name',
            'handler': 'handler',
            'shortcut': 'Ctrl+X',
        },
    ]
    mode = mock.MagicMock()
    mode.save_timeout = 5
    mode.actions.return_value = [
        {
            'name': 'name',
            'handler': 'handler',
            'shortcut': 'Ctrl+X',
        },
    ]
    ed.modes = {
        'microbit': old_mode,
        'python': mode,
    }
    ed.mode = 'microbit'
    ed.change_mode('python')
    # Check the old mode is closed properly.
    old_mode.remove_repl.assert_called_once_with()
    old_mode.remove_fs.assert_called_once_with()
    old_mode.remove_plotter.assert_called_once_with()
    # Check the new mode is set up correctly.
    assert ed.mode == 'python'
    view.change_mode.assert_called_once_with(mode)
    assert mock_button_bar.connect.call_count == 11
    view.status_bar.set_mode.assert_called_once_with('python')
    view.set_timer.assert_called_once_with(5, ed.autosave)


def test_change_mode_no_timer():
    """
    It should be possible to change modes in the expected fashion (buttons get
    correctly connected to event handlers).
    """
    view = mock.MagicMock()
    mock_button_bar = mock.MagicMock()
    view.button_bar = mock_button_bar
    view.change_mode = mock.MagicMock()
    ed = mu.logic.Editor(view)
    mode = mock.MagicMock()
    mode.save_timeout = 0
    mode.actions.return_value = [
        {
            'name': 'name',
            'handler': 'handler',
            'shortcut': 'Ctrl+X',
        },
    ]
    ed.modes = {
        'python': mode,
    }
    ed.change_mode('python')
    assert ed.mode == 'python'
    view.change_mode.assert_called_once_with(mode)
    assert mock_button_bar.connect.call_count == 11
    view.status_bar.set_mode.assert_called_once_with('python')
    view.stop_timer.assert_called_once_with()


def test_change_mode_reset_breakpoints():
    """
    When changing modes, if the new mode does NOT require a debugger, then
    breakpoints should be reset.
    """
    view = mock.MagicMock()
    mock_tab = mock.MagicMock()
    mock_tab.breakpoint_handles = set([1, 2, 3, ])
    view.widgets = [mock_tab, ]
    ed = mu.logic.Editor(view)
    mode = mock.MagicMock()
    mode.has_debugger = False
    mode.is_debugger = False
    mode.save_timeout = 5
    ed.modes = {
        'microbit': mode,
        'debug': mock.MagicMock(),
    }
    ed.mode = 'debug'
    ed.change_mode('microbit')
    assert ed.mode == 'microbit'
    assert mock_tab.breakpoint_handles == set()
    mock_tab.reset_annotations.assert_called_once_with()


def test_autosave():
    """
    Ensure the autosave callback does the expected things to the tabs.
    """
    view = mock.MagicMock()
    view.modified = True
    mock_tab = mock.MagicMock()
    mock_tab.path = 'foo'
    mock_tab.isModified.return_value = True
    view.widgets = [mock_tab, ]
    ed = mu.logic.Editor(view)
    with mock.patch('mu.logic.save_and_encode') as mock_save:
        ed.autosave()
    assert mock_save.call_count == 1
    mock_tab.setModified.assert_called_once_with(False)


def test_check_usb():
    """
    Ensure the check_usb callback actually checks for connected USB devices.
    """
    view = mock.MagicMock()
    view.show_confirmation = mock.MagicMock(return_value=QMessageBox.Ok)
    ed = mu.logic.Editor(view)
    ed.change_mode = mock.MagicMock()
    mode_py = mock.MagicMock()
    mode_py.name = "Python3"
    mode_py.runner = None
    mode_py.find_device.return_value = (None, None)
    mode_mb = mock.MagicMock()
    mode_mb.name = 'BBC micro:bit'
    mode_mb.find_device.return_value = ('/dev/ttyUSB0', '12345')
    ed.modes = {
        'microbit': mode_mb,
        'python': mode_py,
    }
    ed.show_status_message = mock.MagicMock()
    ed.check_usb()
    expected = 'Detected new BBC micro:bit device.'
    ed.show_status_message.assert_called_with(expected)
    assert view.show_confirmation.called
    ed.change_mode.assert_called_once_with('microbit')


def test_check_usb_change_mode_cancel():
    """
    Ensure the check_usb doesn't change mode if confirmation cancelled by user.
    """
    view = mock.MagicMock()
    view.show_confirmation = mock.MagicMock(return_value=QMessageBox.Cancel)
    ed = mu.logic.Editor(view)
    ed.change_mode = mock.MagicMock()
    mode_py = mock.MagicMock()
    mode_py.name = "Python3"
    mode_py.runner = None
    mode_py.find_device.return_value = (None, None)
    mode_cp = mock.MagicMock()
    mode_cp.name = 'CircuitPlayground'
    mode_cp.find_device.return_value = ('/dev/ttyUSB1', '12345')
    ed.modes = {
        'circuitplayground': mode_cp,
        'python': mode_py,
    }
    ed.show_status_message = mock.MagicMock()
    ed.check_usb()
    expected = 'Detected new CircuitPlayground device.'
    ed.show_status_message.assert_called_with(expected)
    assert view.show_confirmation.called
    ed.change_mode.assert_not_called()


def test_check_usb_already_in_mode():
    """
    Ensure the check_usb doesn't ask to change mode if already selected.
    """
    view = mock.MagicMock()
    view.show_confirmation = mock.MagicMock(return_value=QMessageBox.Ok)
    ed = mu.logic.Editor(view)
    ed.change_mode = mock.MagicMock()
    mode_mb = mock.MagicMock()
    mode_mb.name = 'BBC micro:bit'
    mode_mb.find_device.return_value = ('/dev/ttyUSB0', '12345')
    mode_cp = mock.MagicMock()
    mode_cp.find_device.return_value = (None, None)
    ed.modes = {
        'microbit': mode_mb,
        'circuitplayground': mode_cp
    }
    ed.mode = 'microbit'
    ed.show_status_message = mock.MagicMock()
    ed.check_usb()
    view.show_confirmation.assert_not_called()
    ed.change_mode.assert_not_called()


def test_check_usb_currently_running_code():
    """
    Ensure the check_usb doesn't ask to change mode if the current mode is
    running code.
    """
    view = mock.MagicMock()
    view.show_confirmation = mock.MagicMock(return_value=QMessageBox.Ok)
    ed = mu.logic.Editor(view)
    ed.change_mode = mock.MagicMock()
    mode_py = mock.MagicMock()
    mode_py.name = "Python3"
    mode_py.runner = True
    mode_py.find_device.return_value = (None, None)
    mode_mb = mock.MagicMock()
    mode_mb.name = 'BBC micro:bit'
    mode_mb.find_device.return_value = ('/dev/ttyUSB0', '12345')
    ed.modes = {
        'microbit': mode_mb,
        'python': mode_py,
    }
    ed.show_status_message = mock.MagicMock()
    ed.check_usb()
    view.show_confirmation.assert_not_called()
    ed.change_mode.assert_not_called()


def test_check_usb_multiple_devices():
    """
    Ensure the check_usb doesn't ask to change mode if multiple devices found.
    """
    view = mock.MagicMock()
    view.show_confirmation = mock.MagicMock(return_value=QMessageBox.Ok)
    ed = mu.logic.Editor(view)
    ed.change_mode = mock.MagicMock()
    mode_py = mock.MagicMock()
    mode_py.name = "Python3"
    mode_py.runner = None
    mode_py.find_device.return_value = (None, None)
    mode_mb = mock.MagicMock()
    mode_mb.name = 'BBC micro:bit'
    mode_mb.find_device.return_value = ('/dev/ttyUSB0', '12345')
    mode_cp = mock.MagicMock()
    mode_cp.name = 'CircuitPlayground'
    mode_cp.find_device.return_value = ('/dev/ttyUSB1', '54321')
    ed.modes = {
        'microbit': mode_mb,
        'circuitplayground': mode_cp,
        'python': mode_py,
    }
    ed.show_status_message = mock.MagicMock()
    ed.check_usb()
    expected_mb = mock.call('Detected new BBC micro:bit device.')
    expected_cp = mock.call('Detected new CircuitPlayground device.')
    ed.show_status_message.assert_has_calls((expected_mb, expected_cp),
                                            any_order=True)
    view.show_confirmation.assert_not_called()
    ed.change_mode.assert_not_called()


def test_check_usb_when_selecting_mode_is_silent():
    """
    Ensure the check_usb doesn't ask to change mode if the user has the mode
    selection dialog active (indicated by the selecting_mode flag.
    """
    view = mock.MagicMock()
    view.show_confirmation = mock.MagicMock(return_value=QMessageBox.Cancel)
    ed = mu.logic.Editor(view)
    ed.change_mode = mock.MagicMock()
    mode_py = mock.MagicMock()
    mode_py.name = "Python3"
    mode_py.runner = None
    mode_py.find_device.return_value = (None, None)
    mode_cp = mock.MagicMock()
    mode_cp.name = 'CircuitPlayground'
    mode_cp.find_device.return_value = ('/dev/ttyUSB1', '12345')
    ed.modes = {
        'circuitplayground': mode_cp,
        'python': mode_py,
    }
    ed.show_status_message = mock.MagicMock()
    ed.selecting_mode = True
    ed.check_usb()
    expected = 'Detected new CircuitPlayground device.'
    ed.show_status_message.assert_called_with(expected)
    assert view.show_confirmation.call_count == 0
    ed.change_mode.assert_not_called()


def test_check_usb_remove_disconnected_devices():
    """
    Ensure that if a device is no longer connected, it is removed from
    the set of connected devices.
    """
    view = mock.MagicMock()
    ed = mu.logic.Editor(view)
    ed.modes = {}
    ed.show_status_message = mock.MagicMock()
    ed.connected_devices = {('microbit', '/dev/ttyACM1')}
    ed.check_usb()
    assert len(ed.connected_devices) == 0


def test_show_status_message():
    """
    Ensure the method calls the status_bar in the view layer.
    """
    msg = "Hello, World!"
    view = mock.MagicMock()
    ed = mu.logic.Editor(view)
    ed.show_status_message(msg, 8)
    view.status_bar.set_message.assert_called_once_with(msg, 8000)


def test_debug_toggle_breakpoint_as_debugger():
    """
    If a breakpoint is toggled in debug mode, pass it to the toggle_breakpoint
    method in the debug client.
    """
    view = mock.MagicMock()
    view.current_tab.text.return_value = 'print("Hello")'
    ed = mu.logic.Editor(view)
    mock_debugger = mock.MagicMock()
    mock_debugger.has_debugger = False
    mock_debugger.is_debugger = True
    ed.modes = {
        'debugger': mock_debugger,
    }
    ed.mode = 'debugger'
    ed.debug_toggle_breakpoint(1, 10, False)
    mock_debugger.toggle_breakpoint.assert_called_once_with(10,
                                                            view.current_tab)


def test_debug_toggle_breakpoint_on():
    """
    Toggle the breakpoint on when not in debug mode by tracking it in the
    tab.breakpoint_handles set.
    """
    view = mock.MagicMock()
    view.current_tab.breakpoint_handles = set()
    view.current_tab.markersAtLine.return_value = False
    view.current_tab.markerAdd.return_value = 999  # the tracked marker handle.
    ed = mu.logic.Editor(view)
    mock_debugger = mock.MagicMock()
    mock_debugger.has_debugger = True
    mock_debugger.is_debugger = False
    ed.modes = {
        'python': mock_debugger,
    }
    ed.mode = 'python'
    with mock.patch('mu.logic.is_breakpoint_line', return_value=True):
        ed.debug_toggle_breakpoint(1, 10, False)
    view.current_tab.markerAdd.\
        assert_called_once_with(10, view.current_tab.BREAKPOINT_MARKER)
    assert 999 in view.current_tab.breakpoint_handles


def test_debug_toggle_breakpoint_off():
    """
    Toggle the breakpoint off when not in debug mode by tracking it in the
    tab.breakpoint_handles set.
    """
    view = mock.MagicMock()
    view.current_tab.breakpoint_handles = set([10, ])
    ed = mu.logic.Editor(view)
    mock_debugger = mock.MagicMock()
    mock_debugger.has_debugger = True
    mock_debugger.is_debugger = False
    ed.modes = {
        'python': mock_debugger,
    }
    ed.mode = 'python'
    with mock.patch('mu.logic.is_breakpoint_line', return_value=True):
        ed.debug_toggle_breakpoint(1, 10, False)
    view.current_tab.markerDelete.\
        assert_called_once_with(10, -1)


def test_debug_toggle_breakpoint_on_invalid_breakpoint_line():
    """
    If a breakpoint is toggled on, it won't work if the line isn't a valid
    breakpoint line.
    """
    view = mock.MagicMock()
    view.current_tab.text.return_value = '#print("Hello")'
    ed = mu.logic.Editor(view)
    mock_debugger = mock.MagicMock()
    mock_debugger.has_debugger = False
    mock_debugger.is_debugger = True
    ed.modes = {
        'debugger': mock_debugger,
    }
    ed.mode = 'debugger'
    ed.debug_toggle_breakpoint(1, 10, False)
    assert view.show_message.call_count == 1


def test_debug_toggle_breakpoint_off_invalid_breakpoint_line():
    """
    It should be possible to remove breakpoints from *invalid* breakpoint
    lines.
    """
    view = mock.MagicMock()
    view.current_tab.text.return_value = '#print("Hello")'
    view.current_tab.markersAtLine.return_value = True
    view.current_tab.breakpoint_handles = set([10, ])
    ed = mu.logic.Editor(view)
    mock_mode = mock.MagicMock()
    mock_mode.has_debugger = True
    mock_mode.is_debugger = False
    ed.modes = {
        'python': mock_mode,
    }
    ed.mode = 'python'
    ed.debug_toggle_breakpoint(1, 10, False)
    view.current_tab.markerDelete.assert_called_once_with(10, -1)


def test_rename_tab_no_tab_id():
    """
    If no tab id is supplied (i.e. this method was triggered by the shortcut
    instead of the double-click event), then use the tab currently in focus.
    """
    view = mock.MagicMock()
    view.get_save_path.return_value = 'foo'
    mock_tab = mock.MagicMock()
    mock_tab.path = 'old.py'
    view.current_tab = mock_tab
    ed = mu.logic.Editor(view)
    ed.save = mock.MagicMock()
    ed.check_for_shadow_module = mock.MagicMock(return_value=False)
    ed.rename_tab()
    view.get_save_path.assert_called_once_with('old.py')
    assert mock_tab.path == 'foo.py'
    ed.save.assert_called_once_with()


def test_rename_tab():
    """
    If there's a tab id, the function being tested is reacting to a double-tap
    so make sure the expected tab is grabbed from the view.
    """
    view = mock.MagicMock()
    view.get_save_path.return_value = 'foo'
    mock_tab = mock.MagicMock()
    mock_tab.path = 'old.py'
    view.tabs.widget.return_value = mock_tab
    ed = mu.logic.Editor(view)
    ed.save = mock.MagicMock()
    ed.check_for_shadow_module = mock.MagicMock(return_value=False)
    ed.rename_tab(1)
    view.get_save_path.assert_called_once_with('old.py')
    view.tabs.widget.assert_called_once_with(1)
    assert mock_tab.path == 'foo.py'
    ed.save.assert_called_once_with()


def test_rename_tab_with_shadow_module():
    """
    If the user attempts to rename the tab to a filename which shadows a
    Python module, then a warning should appear and the process aborted.
    """
    view = mock.MagicMock()
    view.get_save_path.return_value = 'foo'
    mock_tab = mock.MagicMock()
    mock_tab.path = 'old.py'
    view.tabs.widget.return_value = mock_tab
    ed = mu.logic.Editor(view)
    ed.save = mock.MagicMock()
    ed.check_for_shadow_module = mock.MagicMock(return_value=True)
    ed.rename_tab(1)
    view.get_save_path.assert_called_once_with('old.py')
    view.tabs.widget.assert_called_once_with(1)
    assert view.show_message.call_count == 1
    assert mock_tab.path == 'old.py'
    assert ed.save.call_count == 0


def test_rename_tab_avoid_duplicating_other_tab_name():
    """
    If the user attempts to rename the tab to a filename used by another tab
    then show an error message and don't rename anything.
    """
    view = mock.MagicMock()
    view.get_save_path.return_value = 'foo'
    mock_other_tab = mock.MagicMock()
    mock_other_tab.path = 'foo.py'
    view.widgets = [mock_other_tab, ]
    mock_tab = mock.MagicMock()
    mock_tab.path = 'old.py'
    view.tabs.widget.return_value = mock_tab
    ed = mu.logic.Editor(view)
    ed.check_for_shadow_module = mock.MagicMock(return_value=False)
    ed.rename_tab(1)
    view.show_message.assert_called_once_with('Could not rename file.',
                                              'A file of that name is already '
                                              'open in Mu.')
    assert mock_tab.path == 'old.py'


def test_logic_independent_import_logic():
    """
    It should be possible to import the logic and app
    modules from the mu package independently of each
    other.
    """
    subprocess.run([sys.executable, "-c", "from mu import logic"], check=True)


def test_logic_independent_import_app():
    """
    It should be possible to import the logic and app
    modules from the mu package independently of each
    other.
    """
    subprocess.run([sys.executable, "-c", "from mu import app"], check=True)


#
# Tests for newline detection
# Mu should detect the majority newline convention
# in a loaded file and use that convention when writing
# the file out again. Internally all newlines are MU_NEWLINE
#

def test_read_newline_no_text():
    """If the file being loaded is empty, use the platform default newline
    """
    with generate_python_file() as filepath:
        text, newline = mu.logic.read_and_decode(filepath)
        assert text.count("\r\n") == 0
        assert newline == os.linesep


def test_read_newline_all_unix():
    """If the file being loaded has only the Unix convention, use that
    """
    with generate_python_file("abc\ndef") as filepath:
        text, newline = mu.logic.read_and_decode(filepath)
        assert text.count("\r\n") == 0
        assert newline == "\n"


def test_read_newline_all_windows():
    """If the file being loaded has only the Windows convention, use that
    """
    with generate_python_file("abc\r\ndef") as filepath:
        text, newline = mu.logic.read_and_decode(filepath)
        assert text.count("\r\n") == 0
        assert newline == "\r\n"


def test_read_newline_most_unix():
    """If the file being loaded has mostly the Unix convention, use that
    """
    with generate_python_file("\nabc\r\ndef\n") as filepath:
        text, newline = mu.logic.read_and_decode(filepath)
        assert text.count("\r\n") == 0
        assert newline == "\n"


def test_read_newline_most_windows():
    """If the file being loaded has mostly the Windows convention, use that
    """
    with generate_python_file("\r\nabc\ndef\r\n") as filepath:
        text, newline = mu.logic.read_and_decode(filepath)
        assert text.count("\r\n") == 0
        assert newline == "\r\n"


def test_read_newline_equal_match():
    """If the file being loaded has an equal number of Windows and
    Unix newlines, use the platform default
    """
    with generate_python_file("\r\nabc\ndef") as filepath:
        text, newline = mu.logic.read_and_decode(filepath)
        assert text.count("\r\n") == 0
        assert newline == os.linesep


#
# When writing Mu should honour the line-ending convention found inbound
#
def test_write_newline_to_unix():
    """If the file had Unix newlines it should be saved with Unix newlines

    (In principle this check is unnecessary as Unix newlines are currently
    the Mu internal default; but we leave it here in case that situation
    changes)
    """
    with generate_python_file() as filepath:
        test_string = "\r\n".join("the cat sat on the mat".split())
        mu.logic.save_and_encode(test_string, filepath, "\n")
        with open(filepath, newline="") as f:
            text = f.read()
            assert text.count("\r\n") == 0
            assert text.count("\n") == test_string.count("\r\n")


def test_write_newline_to_windows():
    """If the file had Windows newlines it should be saved with Windows
    newlines
    """
    with generate_python_file() as filepath:
        test_string = "\n".join("the cat sat on the mat".split())
        mu.logic.save_and_encode(test_string, filepath, "\r\n")
        with open(filepath, newline="") as f:
            text = f.read()
            assert len(re.findall("[^\r]\n", text)) == 0
            assert text.count("\r\n") == test_string.count("\n")


#
# Generate a Unicode test string which includes all the usual
# 7-bit characters but also an 8th-bit range which tends to
# trip things up between encodings
#
BYTES_TEST_STRING = bytes(range(0x20, 0x80)) + bytes(range(0xa0, 0xff))
UNICODE_TEST_STRING = BYTES_TEST_STRING.decode("iso-8859-1")


#
# Tests for encoding detection
# Mu should detect:
# - BOM (UTF8/16)
# - Encoding cooke, eg # -*- coding: utf-8 -*-
# - fallback to the platform default (locale.getpreferredencoding())
#
def test_read_utf8bom():
    """Successfully decode from utf-8 encoded with BOM
    """
    with generate_python_file() as filepath:
        with open(filepath, "w", encoding="utf-8-sig") as f:
            f.write(UNICODE_TEST_STRING)
        text, _ = mu.logic.read_and_decode(filepath)
        assert text == UNICODE_TEST_STRING


def test_read_utf16bebom():
    """Successfully decode from utf-16 BE encoded with BOM
    """
    with generate_python_file() as filepath:
        with open(filepath, "wb") as f:
            f.write(codecs.BOM_UTF16_BE)
            f.write(UNICODE_TEST_STRING.encode("utf-16-be"))
        text, _ = mu.logic.read_and_decode(filepath)
        assert text == UNICODE_TEST_STRING


def test_read_utf16lebom():
    """Successfully decode from utf-16 LE encoded with BOM
    """
    with generate_python_file() as filepath:
        with open(filepath, "wb") as f:
            f.write(codecs.BOM_UTF16_LE)
            f.write(UNICODE_TEST_STRING.encode("utf-16-le"))
        text, _ = mu.logic.read_and_decode(filepath)
        assert text == UNICODE_TEST_STRING


def test_read_encoding_cookie():
    """Successfully decode from iso-8859-1 with an encoding cookie
    """
    encoding_cookie = ENCODING_COOKIE.replace(
        mu.logic.ENCODING, "iso-8859-1")
    test_string = encoding_cookie + UNICODE_TEST_STRING
    with generate_python_file() as filepath:
        with open(filepath, "wb") as f:
            f.write(test_string.encode("iso-8859-1"))
        text, _ = mu.logic.read_and_decode(filepath)
        assert text == test_string


def test_read_encoding_mu_default():
    """Successfully decode from the mu default
    """
    test_string = UNICODE_TEST_STRING.encode(mu.logic.ENCODING)
    with generate_python_file() as filepath:
        with open(filepath, "wb") as f:
            f.write(test_string)
        text, _ = mu.logic.read_and_decode(filepath)
        assert text == UNICODE_TEST_STRING


def test_read_encoding_default():
    """Successfully decode from the default locale
    """
    test_string = UNICODE_TEST_STRING.encode(locale.getpreferredencoding())
    with generate_python_file() as filepath:
        with open(filepath, "wb") as f:
            f.write(test_string)
        text, _ = mu.logic.read_and_decode(filepath)
        assert text == UNICODE_TEST_STRING


def test_read_encoding_unsuccessful():
    """Fail to decode encoded text
    """
    #
    # Have to work quite hard to produce text which will definitely
    # fail to decode since UTF-8 and cp1252 (the default on this
    # computer) will, between them, decode nearly anything!
    #
    with generate_python_file() as filepath:
        with open(filepath, "wb") as f:
            f.write(codecs.BOM_UTF8)
            f.write(b"\xd8\x00")
        with pytest.raises(UnicodeDecodeError):
            text, _ = mu.logic.read_and_decode(filepath)


#
# When writing, if the text has an encoding cookie, then that encoding
# should be used. Otherwise, UTF-8 should be used and no encoding cookie
# added
#
def test_write_encoding_cookie_no_cookie():
    """If the text has no cookie of its own utf-8 will be used
    when saving and no cookie added
    """
    test_string = UNICODE_TEST_STRING
    with generate_python_file() as filepath:
        mu.logic.save_and_encode(test_string, filepath)
        with open(filepath, encoding=mu.logic.ENCODING) as f:
            for line in f:
                assert line == test_string
                break


def test_write_encoding_cookie_existing_cookie():
    """If the text has a encoding cookie of its own then that encoding will
    be used when saving and no change made to the cookie
    """
    encoding = "iso-8859-1"
    cookie = ENCODING_COOKIE.replace(mu.logic.ENCODING, encoding)
    test_string = cookie + UNICODE_TEST_STRING
    with generate_python_file() as filepath:
        mu.logic.save_and_encode(test_string, filepath)
        with open(filepath, encoding=encoding) as f:
            assert next(f) == cookie
            assert next(f) == UNICODE_TEST_STRING


def test_write_invalid_codec():
    """If an encoding cookie is present but specifies an unknown codec,
    utf-8 will be used instead
    """
    encoding = "INVALID"
    cookie = ENCODING_COOKIE.replace(mu.logic.ENCODING, encoding)
    test_string = cookie + UNICODE_TEST_STRING
    with generate_python_file() as filepath:
        mu.logic.save_and_encode(test_string, filepath)
        with open(filepath, encoding=mu.logic.ENCODING) as f:
            assert next(f) == cookie
            assert next(f) == UNICODE_TEST_STRING


def test_handle_open_file():
    """
    Ensure on_open_file event handler fires as expected with the editor's
    direct_load when the view's open_file signal is emitted.
    """
    class Dummy(QObject):
        open_file = pyqtSignal(str)
    view = Dummy()
    edit = mu.logic.Editor(view)
    m = mock.MagicMock()
    edit.direct_load = m
    view.open_file.emit('/test/path.py')
    m.assert_called_once_with('/test/path.py')


def test_load_cli():
    """
    Ensure loading paths specified from the command line works as expected.
    """
    mock_view = mock.MagicMock()
    ed = mu.logic.Editor(mock_view)
    m = mock.MagicMock()
    ed.direct_load = m
    ed.load_cli(['test.py'])
    m.assert_called_once_with(os.path.abspath('test.py'))

    m = mock.MagicMock()
    ed.direct_load = m
    ed.load_cli([5])
    assert m.call_count == 0


def test_abspath():
    """
    Ensure a set of unique absolute paths is returned, given a list of
    arbitrary paths.
    """
    ed = mu.logic.Editor(mock.MagicMock())
    paths = ['foo', 'bar', 'bar']
    result = ed._abspath(paths)
    assert len(result) == 2
    assert os.path.abspath('foo') in result
    assert os.path.abspath('bar') in result


def test_abspath_fail():
    """
    If given a problematic arbitrary path, _abspath will log the problem but
    continue to process the "good" paths.
    """
    ed = mu.logic.Editor(mock.MagicMock())
    paths = ['foo', 'bar', 5, 'bar']
    with mock.patch('mu.logic.logger.error') as mock_error:
        result = ed._abspath(paths)
        assert mock_error.call_count == 1
    assert len(result) == 2
    assert os.path.abspath('foo') in result
    assert os.path.abspath('bar') in result


def test_find_replace_cancelled():
    """
    If the activated find/replace dialog is cancelled, no status message is
    displayed.
    """
    mock_view = mock.MagicMock()
    mock_view.show_find_replace.return_value = False
    ed = mu.logic.Editor(mock_view)
    ed.show_status_message = mock.MagicMock()
    ed.find_replace()
    ed.show_status_message.call_count == 0


def test_find_replace_no_find():
    """
    If the user fails to supply something to find, display a modal warning
    message to explain the problem.
    """
    mock_view = mock.MagicMock()
    mock_view.show_find_replace.return_value = ('', '', False)
    ed = mu.logic.Editor(mock_view)
    ed.show_message = mock.MagicMock()
    ed.find_replace()
    msg = 'You must provide something to find.'
    info = "Please try again, this time with something in the find box."
    mock_view.show_message.assert_called_once_with(msg, info)


def test_find_replace_find_matched():
    """
    If the user just supplies a find target and it is matched in the code then
    the expected status message should be shown.
    """
    mock_view = mock.MagicMock()
    mock_view.show_find_replace.return_value = ('foo', '', False)
    mock_view.highlight_text.return_value = True
    ed = mu.logic.Editor(mock_view)
    ed.show_status_message = mock.MagicMock()
    ed.find_replace()
    mock_view.highlight_text.assert_called_once_with('foo')
    assert ed.find == 'foo'
    assert ed.replace == ''
    assert ed.global_replace is False
    ed.show_status_message.\
        assert_called_once_with('Highlighting matches for "foo".')


def test_find_replace_find_unmatched():
    """
    If the user just supplies a find target and it is UN-matched in the code
    then the expected status message should be shown.
    """
    mock_view = mock.MagicMock()
    mock_view.show_find_replace.return_value = ('foo', '', False)
    mock_view.highlight_text.return_value = False
    ed = mu.logic.Editor(mock_view)
    ed.show_status_message = mock.MagicMock()
    ed.find_replace()
    ed.show_status_message.\
        assert_called_once_with('Could not find "foo".')


def test_find_replace_replace_no_match():
    """
    If the user supplies both a find and replace target and the find target is
    UN-matched in the code, then the expected status message should be shown.
    """
    mock_view = mock.MagicMock()
    mock_view.show_find_replace.return_value = ('foo', 'bar', False)
    mock_view.replace_text.return_value = 0
    ed = mu.logic.Editor(mock_view)
    ed.show_status_message = mock.MagicMock()
    ed.find_replace()
    assert ed.find == 'foo'
    assert ed.replace == 'bar'
    assert ed.global_replace is False
    mock_view.replace_text.assert_called_once_with('foo', 'bar', False)
    ed.show_status_message.\
        assert_called_once_with('Could not find "foo".')


def test_find_replace_replace_single_match():
    """
    If the user supplies both a find and replace target and the find target is
    matched once in the code, then the expected status message should be shown.
    """
    mock_view = mock.MagicMock()
    mock_view.show_find_replace.return_value = ('foo', 'bar', False)
    mock_view.replace_text.return_value = 1
    ed = mu.logic.Editor(mock_view)
    ed.show_status_message = mock.MagicMock()
    ed.find_replace()
    assert ed.find == 'foo'
    assert ed.replace == 'bar'
    assert ed.global_replace is False
    mock_view.replace_text.assert_called_once_with('foo', 'bar', False)
    ed.show_status_message.\
        assert_called_once_with('Replaced "foo" with "bar".')


def test_find_replace_replace_multi_match():
    """
    If the user supplies both a find and replace target and the find target is
    matched many times in the code, then the expected status message should be
    shown.
    """
    mock_view = mock.MagicMock()
    mock_view.show_find_replace.return_value = ('foo', 'bar', True)
    mock_view.replace_text.return_value = 4
    ed = mu.logic.Editor(mock_view)
    ed.show_status_message = mock.MagicMock()
    ed.find_replace()
    assert ed.find == 'foo'
    assert ed.replace == 'bar'
    assert ed.global_replace is True
    mock_view.replace_text.assert_called_once_with('foo', 'bar', True)
    ed.show_status_message.\
        assert_called_once_with('Replaced 4 matches of "foo" with "bar".')


def test_toggle_comments():
    """
    Ensure the method in the view for toggling comments on and off is called.
    """
    mock_view = mock.MagicMock()
    ed = mu.logic.Editor(mock_view)
    ed.toggle_comments()
    mock_view.toggle_comments.assert_called_once_with()
