#! /usr/bin/env python
## -*- Mode: python; py-indent-offset: 4; indent-tabs-mode: nil; coding: utf-8; -*-
#
# Copyright (c) 2009 University of Washington
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 as
# published by the Free Software Foundation;
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#

import os
import sys
import time
import optparse
import subprocess
import threading
import Queue
import signal
import xml.dom.minidom
import shutil
import re

from utils import get_list_from_file

#
# XXX This should really be part of a waf command to list the configuration
# items relative to optional ns-3 pieces.
#
# A list of interesting configuration items in the waf configuration 
# cache which we may be interested in when deciding on which examples
# to run and how to run them.  These are set by waf during the 
# configuration phase and the corresponding assignments are usually
# found in the associated subdirectory wscript files.
#
interesting_config_items = [
    "NS3_ENABLED_MODULES",
    "NS3_MODULE_PATH",
    "NSC_ENABLED",
    "ENABLE_REAL_TIME",
    "ENABLE_THREADING",
    "ENABLE_EXAMPLES",
    "ENABLE_TESTS",
    "EXAMPLE_DIRECTORIES",
    "ENABLE_PYTHON_BINDINGS",
    "ENABLE_CLICK",
    "ENABLE_BRITE",
    "ENABLE_OPENFLOW",
    "APPNAME",
    "BUILD_PROFILE",
    "VERSION",
    "PYTHON",
]

NSC_ENABLED = False
ENABLE_REAL_TIME = False
ENABLE_THREADING = False
ENABLE_EXAMPLES = True
ENABLE_TESTS = True
ENABLE_CLICK = False
ENABLE_BRITE = False
ENABLE_OPENFLOW = False
EXAMPLE_DIRECTORIES = []
APPNAME = ""
BUILD_PROFILE = ""
VERSION = ""
PYTHON = ""

#
# This will be given a prefix and a suffix when the waf config file is
# read.
#
test_runner_name = "test-runner"

#
# If the user has constrained us to run certain kinds of tests, we can tell waf
# to only build
#
core_kinds = ["bvt", "core", "performance", "system", "unit"]

#
# There are some special cases for test suites that kill valgrind.  This is
# because NSC causes illegal instruction crashes when run under valgrind.
#
core_valgrind_skip_tests = [
    "ns3-tcp-cwnd",
    "nsc-tcp-loss",
    "ns3-tcp-interoperability",
    "routing-click",
    "lte-rr-ff-mac-scheduler",
    "lte-tdmt-ff-mac-scheduler",
    "lte-fdmt-ff-mac-scheduler",
    "lte-pf-ff-mac-scheduler",
    "lte-tta-ff-mac-scheduler",
    "lte-fdbet-ff-mac-scheduler",
    "lte-ttbet-ff-mac-scheduler",
    "lte-fdtbfq-ff-mac-scheduler",
    "lte-tdtbfq-ff-mac-scheduler",
    "lte-pss-ff-mac-scheduler",
]

# 
# There are some special cases for test suites that fail when NSC is
# missing.
#
core_nsc_missing_skip_tests = [
    "ns3-tcp-cwnd",
    "nsc-tcp-loss",
    "ns3-tcp-interoperability",
]

#
# Parse the examples-to-run file if it exists.
#
# This function adds any C++ examples or Python examples that are to be run
# to the lists in example_tests and python_tests, respectively.
#
def parse_examples_to_run_file(
    examples_to_run_path,
    cpp_executable_dir,
    python_script_dir,
    example_tests,
    example_names_original,
    python_tests):

    # Look for the examples-to-run file exists.
    if os.path.exists(examples_to_run_path):

        # Each tuple in the C++ list of examples to run contains
        #
        #     (example_name, do_run, do_valgrind_run)
        #
        # where example_name is the executable to be run, do_run is a
        # condition under which to run the example, and do_valgrind_run is
        # a condition under which to run the example under valgrind.  This
        # is needed because NSC causes illegal instruction crashes with
        # some tests when they are run under valgrind.
        #
        # Note that the two conditions are Python statements that
        # can depend on waf configuration variables.  For example,
        #
        #     ("tcp-nsc-lfn", "NSC_ENABLED == True", "NSC_ENABLED == False"),
        #
        cpp_examples = get_list_from_file(examples_to_run_path, "cpp_examples")
        for example_name, do_run, do_valgrind_run in cpp_examples:

            # Seperate the example name from its arguments.
            example_name_original = example_name
            example_name_parts = example_name.split(' ', 1)
            if len(example_name_parts) == 1:
                example_name      = example_name_parts[0]
                example_arguments = ""
            else:
                example_name      = example_name_parts[0]
                example_arguments = example_name_parts[1]

            # Add the proper prefix and suffix to the example name to
            # match what is done in the wscript file.
            example_name = "%s%s-%s-%s" % (APPNAME, VERSION, example_name, BUILD_PROFILE)

            # Set the full path for the example.
            example_path = os.path.join(cpp_executable_dir, example_name)
            # Add all of the C++ examples that were built, i.e. found
            # in the directory, to the list of C++ examples to run.
            if os.path.exists(example_path):
                # Add any arguments to the path.
                if len(example_name_parts) != 1:
                    example_path = "%s %s" % (example_path, example_arguments)

                # Add this example.
                example_tests.append((example_path, do_run, do_valgrind_run))
                example_names_original.append(example_name_original)
    
        # Each tuple in the Python list of examples to run contains
        #
        #     (example_name, do_run)
        #
        # where example_name is the Python script to be run and
        # do_run is a condition under which to run the example.
        #
        # Note that the condition is a Python statement that can
        # depend on waf configuration variables.  For example,
        #
        #     ("realtime-udp-echo.py", "ENABLE_REAL_TIME == True"),
        #
        python_examples = get_list_from_file(examples_to_run_path, "python_examples")
        for example_name, do_run in python_examples:
            # Seperate the example name from its arguments.
            example_name_parts = example_name.split(' ', 1)
            if len(example_name_parts) == 1:
                example_name      = example_name_parts[0]
                example_arguments = ""
            else:
                example_name      = example_name_parts[0]
                example_arguments = example_name_parts[1]

            # Set the full path for the example.
            example_path = os.path.join(python_script_dir, example_name)

            # Add all of the Python examples that were found to the
            # list of Python examples to run.
            if os.path.exists(example_path):
                # Add any arguments to the path.
                if len(example_name_parts) != 1:
                    example_path = "%s %s" % (example_path, example_arguments)

                # Add this example.
                python_tests.append((example_path, do_run))

#
# The test suites are going to want to output status.  They are running
# concurrently.  This means that unless we are careful, the output of
# the test suites will be interleaved.  Rather than introducing a lock
# file that could unintentionally start serializing execution, we ask
# the tests to write their output to a temporary directory and then 
# put together the final output file when we "join" the test tasks back
# to the main thread.  In addition to this issue, the example programs
# often write lots and lots of trace files which we will just ignore.
# We put all of them into the temp directory as well, so they can be
# easily deleted.
#
TMP_OUTPUT_DIR = "testpy-output"

def read_test(test):
    result = test.find('Result').text
    name = test.find('Name').text
    if not test.find('Time') is None:
        time_real = test.find('Time').get('real')
    else:
        time_real = ''
    return (result, name, time_real)

#
# A simple example of writing a text file with a test result summary.  It is 
# expected that this output will be fine for developers looking for problems.
#
def node_to_text (test, f):
    (result, name, time_real) = read_test(test)
    output = "%s: Test Suite \"%s\" (%s)\n" % (result, name, time_real)
    f.write(output)
    for details in test.findall('FailureDetails'):
        f.write("    Details:\n")
        f.write("      Message:   %s\n" % details.find('Message').text)
        f.write("      Condition: %s\n" % details.find('Condition').text)
        f.write("      Actual:    %s\n" % details.find('Actual').text)
        f.write("      Limit:     %s\n" % details.find('Limit').text)
        f.write("      File:      %s\n" % details.find('File').text)
        f.write("      Line:      %s\n" % details.find('Line').text)
    for child in test.findall('Test'):
        node_to_text(child, f)

def translate_to_text(results_file, text_file):
    f = open(text_file, 'w')
    import xml.etree.ElementTree as ET
    et = ET.parse (results_file)
    for test in et.findall('Test'):
        node_to_text (test, f)

    for example in et.findall('Example'):
        result = example.find('Result').text
        name = example.find('Name').text
        if not example.find('Time') is None:
            time_real = example.find('Time').get('real')
        else:
            time_real = ''
        output = "%s: Example \"%s\" (%s)\n" % (result, name, time_real)
        f.write(output)

    f.close()
    
#
# A simple example of writing an HTML file with a test result summary.  It is 
# expected that this will eventually be made prettier as time progresses and
# we have time to tweak it.  This may end up being moved to a separate module
# since it will probably grow over time.
#
def translate_to_html(results_file, html_file):
    f = open(html_file, 'w')
    f.write("<html>\n")
    f.write("<body>\n")
    f.write("<center><h1>ns-3 Test Results</h1></center>\n")

    #
    # Read and parse the whole results file.
    #
    import xml.etree.ElementTree as ET
    et = ET.parse(results_file)

    #
    # Iterate through the test suites
    #
    f.write("<h2>Test Suites</h2>\n")
    for suite in et.findall('Test'):     
        #
        # For each test suite, get its name, result and execution time info
        #
        (result, name, time) = read_test (suite)

        # 
        # Print a level three header with the result, name and time.  If the 
        # test suite passed, the header is printed in green. If the suite was
        # skipped, print it in orange, otherwise assume something bad happened
        # and print in red.
        #
        if result == "PASS":
            f.write("<h3 style=\"color:green\">%s: %s (%s)</h3>\n" % (result, name, time))
        elif result == "SKIP":
            f.write("<h3 style=\"color:#ff6600\">%s: %s (%s)</h3>\n" % (result, name, time))
        else:
            f.write("<h3 style=\"color:red\">%s: %s (%s)</h3>\n" % (result, name, time))

        #
        # The test case information goes in a table.
        #
        f.write("<table border=\"1\">\n")

        #
        # The first column of the table has the heading Result
        #
        f.write("<th> Result </th>\n")

        #
        # If the suite crashed or is skipped, there is no further information, so just
        # delare a new table row with the result (CRASH or SKIP) in it.  Looks like:
        #
        #   +--------+
        #   | Result |
        #   +--------+
        #   | CRASH  |
        #   +--------+
        #
        # Then go on to the next test suite.  Valgrind and skipped errors look the same.
        #
        if result in ["CRASH", "SKIP", "VALGR"]:
            f.write("<tr>\n")
            if result == "SKIP":
                f.write("<td style=\"color:#ff6600\">%s</td>\n" % result)
            else:
                f.write("<td style=\"color:red\">%s</td>\n" % result)
            f.write("</tr>\n")
            f.write("</table>\n")
            continue

        #
        # If the suite didn't crash, we expect more information, so fill out
        # the table heading row.  Like,
        #
        #   +--------+----------------+------+
        #   | Result | Test Case Name | Time |
        #   +--------+----------------+------+
        #
        f.write("<th>Test Case Name</th>\n")
        f.write("<th> Time </th>\n")

        #
        # If the test case failed, we need to print out some failure details
        # so extend the heading row again.  Like,
        #
        #   +--------+----------------+------+-----------------+
        #   | Result | Test Case Name | Time | Failure Details |
        #   +--------+----------------+------+-----------------+
        #
        if result == "FAIL":
            f.write("<th>Failure Details</th>\n")

        #
        # Now iterate through all of the test cases.
        #
        for case in suite.findall('Test'):

            #
            # Get the name, result and timing information from xml to use in
            # printing table below.
            #
            (result, name, time) = read_test(case)

            #
            # If the test case failed, we iterate through possibly multiple
            # failure details
            #
            if result == "FAIL":
                #
                # There can be multiple failures for each test case.  The first
                # row always gets the result, name and timing information along
                # with the failure details.  Remaining failures don't duplicate
                # this information but just get blanks for readability.  Like,
                #
                #   +--------+----------------+------+-----------------+
                #   | Result | Test Case Name | Time | Failure Details |
                #   +--------+----------------+------+-----------------+
                #   |  FAIL  | The name       | time | It's busted     |   
                #   +--------+----------------+------+-----------------+
                #   |        |                |      | Really broken   |   
                #   +--------+----------------+------+-----------------+
                #   |        |                |      | Busted bad      |   
                #   +--------+----------------+------+-----------------+
                #

                first_row = True
                for details in case.findall('FailureDetails'):

                    #
                    # Start a new row in the table for each possible Failure Detail
                    #
                    f.write("<tr>\n")

                    if first_row:
                        first_row = False
                        f.write("<td style=\"color:red\">%s</td>\n" % result)
                        f.write("<td>%s</td>\n" % name)
                        f.write("<td>%s</td>\n" % time)
                    else:
                        f.write("<td></td>\n")
                        f.write("<td></td>\n")
                        f.write("<td></td>\n")

                    f.write("<td>")
                    f.write("<b>Message: </b>%s, " % details.find('Message').text)
                    f.write("<b>Condition: </b>%s, " % details.find('Condition').text)
                    f.write("<b>Actual: </b>%s, " % details.find('Actual').text)
                    f.write("<b>Limit: </b>%s, " % details.find('Limit').text)
                    f.write("<b>File: </b>%s, " % details.find('File').text)
                    f.write("<b>Line: </b>%s" % details.find('Line').text)
                    f.write("</td>\n")
                    
                    #
                    # End the table row
                    #
                    f.write("</td>\n")
            else:
                #
                # If this particular test case passed, then we just print the PASS
                # result in green, followed by the test case name and its execution
                # time information.  These go off in <td> ... </td> table data.
                # The details table entry is left blank.
                #
                #   +--------+----------------+------+---------+
                #   | Result | Test Case Name | Time | Details |
                #   +--------+----------------+------+---------+
                #   |  PASS  | The name       | time |         |   
                #   +--------+----------------+------+---------+
                #
                f.write("<tr>\n")
                f.write("<td style=\"color:green\">%s</td>\n" % result)
                f.write("<td>%s</td>\n" % name)
                f.write("<td>%s</td>\n" % time)
                f.write("<td></td>\n")
                f.write("</tr>\n")
        #
        # All of the rows are written, so we need to end the table.
        #
        f.write("</table>\n")

    #
    # That's it for all of the test suites.  Now we have to do something about 
    # our examples.
    #
    f.write("<h2>Examples</h2>\n")

    #
    # Example status is rendered in a table just like the suites.
    #
    f.write("<table border=\"1\">\n")

    #
    # The table headings look like,
    #
    #   +--------+--------------+--------------+
    #   | Result | Example Name | Elapsed Time |
    #   +--------+--------------+--------------+
    #
    f.write("<th> Result </th>\n")
    f.write("<th>Example Name</th>\n")
    f.write("<th>Elapsed Time</th>\n")

    #
    # Now iterate through all of the examples
    #
    for example in et.findall("Example"):
        
        #
        # Start a new row for each example
        #
        f.write("<tr>\n")
        
        #
        # Get the result and name of the example in question
        #
        (result, name, time) = read_test(example)

        #
        # If the example either failed or crashed, print its result status
        # in red; otherwise green.  This goes in a <td> ... </td> table data
        #
        if result == "PASS":
            f.write("<td style=\"color:green\">%s</td>\n" % result)
        elif result == "SKIP":
            f.write("<td style=\"color:#ff6600\">%s</fd>\n" % result)
        else:
            f.write("<td style=\"color:red\">%s</td>\n" % result)

        #
        # Write the example name as a new tag data.
        #
        f.write("<td>%s</td>\n" % name)

        #
        # Write the elapsed time as a new tag data.
        #
        f.write("<td>%s</td>\n" % time)

        #
        # That's it for the current example, so terminate the row.
        #
        f.write("</tr>\n")

    #
    # That's it for the table of examples, so terminate the table.
    #
    f.write("</table>\n")

    #
    # And that's it for the report, so finish up.
    #
    f.write("</body>\n")
    f.write("</html>\n")
    f.close()
    
#
# Python Control-C handling is broken in the presence of multiple threads.  
# Signals get delivered to the runnable/running thread by default and if 
# it is blocked, the signal is simply ignored.  So we hook sigint and set 
# a global variable telling the system to shut down gracefully.
#
thread_exit = False

def sigint_hook(signal, frame):
    global thread_exit
    thread_exit = True
    return 0


#
# In general, the build process itself naturally takes care of figuring out
# which tests are built into the test runner.  For example, if waf configure
# determines that ENABLE_EMU is false due to some missing dependency,
# the tests for the emu net device simply will not be built and will 
# therefore not be included in the built test runner.
#
# Examples, however, are a different story.  In that case, we are just given
# a list of examples that could be run.  Instead of just failing, for example,
# nsc-tcp-zoo if NSC is not present, we look into the waf saved configuration
# for relevant configuration items.  
#
# XXX This function pokes around in the waf internal state file.  To be a
# little less hacky, we should add a commmand to waf to return this info
# and use that result.
#
def read_waf_config():
    for line in open(".lock-waf_" + sys.platform + "_build", "rt"):
        if line.startswith("top_dir ="):
            key, val = line.split('=')
            top_dir = eval(val.strip())
        if line.startswith("out_dir ="):
            key, val = line.split('=')
            out_dir = eval(val.strip())
    global NS3_BASEDIR
    NS3_BASEDIR = top_dir
    global NS3_BUILDDIR
    NS3_BUILDDIR = out_dir
    for line in open("%s/c4che/_cache.py" % out_dir).readlines():
        for item in interesting_config_items:
            if line.startswith(item):
                exec(line, globals())

    if options.verbose:
        for item in interesting_config_items:
            print "%s ==" % item, eval(item)

#
# It seems pointless to fork a process to run waf to fork a process to run
# the test runner, so we just run the test runner directly.  The main thing 
# that waf would do for us would be to sort out the shared library path but
# we can deal with that easily and do here.
#
# There can be many different ns-3 repositories on a system, and each has 
# its own shared libraries, so ns-3 doesn't hardcode a shared library search
# path -- it is cooked up dynamically, so we do that too.
#
def make_paths():
    have_DYLD_LIBRARY_PATH = False
    have_LD_LIBRARY_PATH = False
    have_PATH = False
    have_PYTHONPATH = False

    keys = os.environ.keys()
    for key in keys:
        if key == "DYLD_LIBRARY_PATH":
            have_DYLD_LIBRARY_PATH = True
        if key == "LD_LIBRARY_PATH":
            have_LD_LIBRARY_PATH = True
        if key == "PATH":
            have_PATH = True
        if key == "PYTHONPATH":
            have_PYTHONPATH = True

    pypath = os.environ["PYTHONPATH"] = os.path.join (NS3_BUILDDIR, "bindings", "python")

    if not have_PYTHONPATH:
        os.environ["PYTHONPATH"] = pypath
    else:
        os.environ["PYTHONPATH"] += ":" + pypath

    if options.verbose:
        print "os.environ[\"PYTHONPATH\"] == %s" % os.environ["PYTHONPATH"]

    if sys.platform == "darwin":
        if not have_DYLD_LIBRARY_PATH:
            os.environ["DYLD_LIBRARY_PATH"] = ""
        for path in NS3_MODULE_PATH:
            os.environ["DYLD_LIBRARY_PATH"] += ":" + path
        if options.verbose:
            print "os.environ[\"DYLD_LIBRARY_PATH\"] == %s" % os.environ["DYLD_LIBRARY_PATH"]
    elif sys.platform == "win32":
        if not have_PATH:
            os.environ["PATH"] = ""
        for path in NS3_MODULE_PATH:
            os.environ["PATH"] += ';' + path
        if options.verbose:
            print "os.environ[\"PATH\"] == %s" % os.environ["PATH"]
    elif sys.platform == "cygwin":
        if not have_PATH:
            os.environ["PATH"] = ""
        for path in NS3_MODULE_PATH:
            os.environ["PATH"] += ":" + path
        if options.verbose:
            print "os.environ[\"PATH\"] == %s" % os.environ["PATH"]
    else:
        if not have_LD_LIBRARY_PATH:
            os.environ["LD_LIBRARY_PATH"] = ""
        for path in NS3_MODULE_PATH:
            os.environ["LD_LIBRARY_PATH"] += ":" + path
        if options.verbose:
            print "os.environ[\"LD_LIBRARY_PATH\"] == %s" % os.environ["LD_LIBRARY_PATH"]

#
# Short note on generating suppressions:
#
# See the valgrind documentation for a description of suppressions.  The easiest
# way to generate a suppression expression is by using the valgrind 
# --gen-suppressions option.  To do that you have to figure out how to run the 
# test in question.
#
# If you do "test.py -v -g -s <suitename> then test.py will output most of what
# you need.  For example, if you are getting a valgrind error in the
# devices-mesh-dot11s-regression test suite, you can run:
#
#   ./test.py -v -g -s devices-mesh-dot11s-regression 
#
# You should see in the verbose output something that looks like:
#
#   Synchronously execute valgrind --suppressions=/home/craigdo/repos/ns-3-allinone-dev/ns-3-dev/testpy.supp
#   --leak-check=full --error-exitcode=2 /home/craigdo/repos/ns-3-allinone-dev/ns-3-dev/build/debug/utils/ns3-dev-test-runner-debug 
#   --suite=devices-mesh-dot11s-regression --basedir=/home/craigdo/repos/ns-3-allinone-dev/ns-3-dev 
#   --tempdir=testpy-output/2010-01-12-22-47-50-CUT 
#   --out=testpy-output/2010-01-12-22-47-50-CUT/devices-mesh-dot11s-regression.xml
#
# You need to pull out the useful pieces, and so could run the following to 
# reproduce your error:
#
#   valgrind --suppressions=/home/craigdo/repos/ns-3-allinone-dev/ns-3-dev/testpy.supp
#   --leak-check=full --error-exitcode=2 /home/craigdo/repos/ns-3-allinone-dev/ns-3-dev/build/debug/utils/ns3-dev-test-runner-debug 
#   --suite=devices-mesh-dot11s-regression --basedir=/home/craigdo/repos/ns-3-allinone-dev/ns-3-dev 
#   --tempdir=testpy-output 
#
# Hint: Use the first part of the command as is, and point the "tempdir" to 
# somewhere real.  You don't need to specify an "out" file.
#
# When you run the above command you should see your valgrind error.  The 
# suppression expression(s) can be generated by adding the --gen-suppressions=yes
# option to valgrind.  Use something like:
#
#   valgrind --gen-suppressions=yes --suppressions=/home/craigdo/repos/ns-3-allinone-dev/ns-3-dev/testpy.supp
#   --leak-check=full --error-exitcode=2 /home/craigdo/repos/ns-3-allinone-dev/ns-3-dev/build/debug/utils/ns3-dev-test-runner-debug 
#   --suite=devices-mesh-dot11s-regression --basedir=/home/craigdo/repos/ns-3-allinone-dev/ns-3-dev 
#   --tempdir=testpy-output 
#
# Now when valgrind detects an error it will ask:
#
#   ==27235== ---- Print suppression ? --- [Return/N/n/Y/y/C/c] ----
#
# to which you just enter 'y'<ret>.
#
# You will be provided with a suppression expression that looks something like
# the following:
#   {
#     <insert_a_suppression_name_here>
#     Memcheck:Addr8
#     fun:_ZN3ns36dot11s15HwmpProtocolMac8SendPreqESt6vectorINS0_6IePreqESaIS3_EE
#     fun:_ZN3ns36dot11s15HwmpProtocolMac10SendMyPreqEv
#     fun:_ZN3ns36dot11s15HwmpProtocolMac18RequestDestinationENS_12Mac48AddressEjj
#     ...
#     the rest of the stack frame
#     ...
#   }
#
# You need to add a supression name which will only be printed out by valgrind in 
# verbose mode (but it needs to be there in any case).  The entire stack frame is
# shown to completely characterize the error, but in most cases you won't need 
# all of that info.  For example, if you want to turn off all errors that happen
# when the function (fun:) is called, you can just delete the rest of the stack
# frame.  You can also use wildcards to make the mangled signatures more readable.
#
# I added the following to the testpy.supp file for this particular error:
#
#   {
#     Supress invalid read size errors in SendPreq() when using HwmpProtocolMac
#     Memcheck:Addr8
#     fun:*HwmpProtocolMac*SendPreq*
#   }
#
# Now, when you run valgrind the error will be suppressed.
#
VALGRIND_SUPPRESSIONS_FILE = "testpy.supp"

def run_job_synchronously(shell_command, directory, valgrind, is_python, build_path=""):
    suppressions_path = os.path.join (NS3_BASEDIR, VALGRIND_SUPPRESSIONS_FILE)

    if is_python:
        path_cmd = PYTHON[0] + " " + os.path.join (NS3_BASEDIR, shell_command)
    else:
        if len(build_path):
            path_cmd = os.path.join (build_path, shell_command)
        else:
            path_cmd = os.path.join (NS3_BUILDDIR, shell_command)

    if valgrind:
        cmd = "valgrind --suppressions=%s --leak-check=full --show-reachable=yes --error-exitcode=2 %s" % (suppressions_path, 
            path_cmd)
    else:
        cmd = path_cmd

    if options.verbose:
        print "Synchronously execute %s" % cmd

    start_time = time.time()
    proc = subprocess.Popen(cmd, shell = True, cwd = directory, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    stdout_results, stderr_results = proc.communicate()
    elapsed_time = time.time() - start_time

    retval = proc.returncode

    #
    # valgrind sometimes has its own idea about what kind of memory management
    # errors are important.  We want to detect *any* leaks, so the way to do 
    # that is to look for the presence of a valgrind leak summary section.
    #
    # If another error has occurred (like a test suite has failed), we don't 
    # want to trump that error, so only do the valgrind output scan if the 
    # test has otherwise passed (return code was zero).
    #
    if valgrind and retval == 0 and "== LEAK SUMMARY:" in stderr_results:
        retval = 2
    
    if options.verbose:
        print "Return code = ", retval
        print "stderr = ", stderr_results

    return (retval, stdout_results, stderr_results, elapsed_time)

#
# This class defines a unit of testing work.  It will typically refer to
# a test suite to run using the test-runner, or an example to run directly.
#
class Job:
    def __init__(self):
        self.is_break = False
        self.is_skip = False
        self.is_example = False
        self.is_pyexample = False
        self.shell_command = ""
        self.display_name = ""
        self.basedir = ""
        self.tempdir = ""
        self.cwd = ""
        self.tmp_file_name = ""
        self.returncode = False
        self.elapsed_time = 0
        self.build_path = ""

    #
    # A job is either a standard job or a special job indicating that a worker
    # thread should exist.  This special job is indicated by setting is_break 
    # to true.
    #
    def set_is_break(self, is_break):
        self.is_break = is_break

    #
    # If a job is to be skipped, we actually run it through the worker threads
    # to keep the PASS, FAIL, CRASH and SKIP processing all in one place.
    #
    def set_is_skip(self, is_skip):
        self.is_skip = is_skip

    #
    # Examples are treated differently than standard test suites.  This is
    # mostly because they are completely unaware that they are being run as 
    # tests.  So we have to do some special case processing to make them look
    # like tests.
    #
    def set_is_example(self, is_example):
        self.is_example = is_example

    #
    # Examples are treated differently than standard test suites.  This is
    # mostly because they are completely unaware that they are being run as 
    # tests.  So we have to do some special case processing to make them look
    # like tests.
    #
    def set_is_pyexample(self, is_pyexample):
        self.is_pyexample = is_pyexample

    #
    # This is the shell command that will be executed in the job.  For example,
    #
    #  "utils/ns3-dev-test-runner-debug --test-name=some-test-suite"
    #
    def set_shell_command(self, shell_command):
        self.shell_command = shell_command

    #
    # This is the build path where ns-3 was built.  For example,
    #
    #  "/home/craigdo/repos/ns-3-allinone-test/ns-3-dev/build/debug"
    #
    def set_build_path(self, build_path):
        self.build_path = build_path

    #
    # This is the dispaly name of the job, typically the test suite or example 
    # name.  For example,
    #
    #  "some-test-suite" or "udp-echo"
    #
    def set_display_name(self, display_name):
        self.display_name = display_name

    #
    # This is the base directory of the repository out of which the tests are
    # being run.  It will be used deep down in the testing framework to determine
    # where the source directory of the test was, and therefore where to find 
    # provided test vectors.  For example,
    #
    #  "/home/user/repos/ns-3-dev"
    #
    def set_basedir(self, basedir):
        self.basedir = basedir

    #
    # This is the directory to which a running test suite should write any 
    # temporary files.
    #
    def set_tempdir(self, tempdir):
        self.tempdir = tempdir

    #
    # This is the current working directory that will be given to an executing
    # test as it is being run.  It will be used for examples to tell them where
    # to write all of the pcap files that we will be carefully ignoring.  For
    # example,
    #
    #  "/tmp/unchecked-traces"
    #
    def set_cwd(self, cwd):
        self.cwd = cwd

    #
    # This is the temporary results file name that will be given to an executing 
    # test as it is being run.  We will be running all of our tests in parallel
    # so there must be multiple temporary output files.  These will be collected
    # into a single XML file at the end and then be deleted.  
    #
    def set_tmp_file_name(self, tmp_file_name):
        self.tmp_file_name = tmp_file_name

    #
    # The return code received when the job process is executed.
    #
    def set_returncode(self, returncode):
        self.returncode = returncode

    #
    # The elapsed real time for the job execution.
    #
    def set_elapsed_time(self, elapsed_time):
        self.elapsed_time = elapsed_time

#
# The worker thread class that handles the actual running of a given test.
# Once spawned, it receives requests for work through its input_queue and
# ships the results back through the output_queue.
#
class worker_thread(threading.Thread):
    def __init__(self, input_queue, output_queue):
        threading.Thread.__init__(self)
        self.input_queue = input_queue
        self.output_queue = output_queue

    def run(self):
        while True:
            job = self.input_queue.get()
            #
            # Worker threads continue running until explicitly told to stop with
            # a special job.
            #
            if job.is_break:
                return
            #
            # If the global interrupt handler sets the thread_exit variable,
            # we stop doing real work and just report back a "break" in the
            # normal command processing has happened.
            #
            if thread_exit == True:
                job.set_is_break(True)
                self.output_queue.put(job)
                continue

            #
            # If we are actually supposed to skip this job, do so.  Note that
            # if is_skip is true, returncode is undefined.
            #
            if job.is_skip:
                if options.verbose:
                    print "Skip %s" % job.shell_command
                self.output_queue.put(job)
                continue

            #
            # Otherwise go about the business of running tests as normal.
            #
            else:
                if options.verbose:
                    print "Launch %s" % job.shell_command

                if job.is_example or job.is_pyexample:
                    #
                    # If we have an example, the shell command is all we need to
                    # know.  It will be something like "examples/udp/udp-echo" or 
                    # "examples/wireless/mixed-wireless.py"
                    #
                    (job.returncode, standard_out, standard_err, et) = run_job_synchronously(job.shell_command, 
                        job.cwd, options.valgrind, job.is_pyexample, job.build_path)
                else:
                    #
                    # If we're a test suite, we need to provide a little more info
                    # to the test runner, specifically the base directory and temp
                    # file name
                    #
                    if options.update_data:
                        update_data = '--update-data'
                    else:
                        update_data = ''
                    (job.returncode, standard_out, standard_err, et) = run_job_synchronously(job.shell_command + 
                        " --xml --tempdir=%s --out=%s %s" % (job.tempdir, job.tmp_file_name, update_data), 
                        job.cwd, options.valgrind, False)

                job.set_elapsed_time(et)

                if options.verbose:
                    print "returncode = %d" % job.returncode
                    print "---------- begin standard out ----------"
                    print standard_out
                    print "---------- begin standard err ----------"
                    print standard_err
                    print "---------- end standard err ----------"

                self.output_queue.put(job)

#
# This is the main function that does the work of interacting with the
# test-runner itself.
#
def run_tests():
    #
    # Pull some interesting configuration information out of waf, primarily
    # so we can know where executables can be found, but also to tell us what
    # pieces of the system have been built.  This will tell us what examples 
    # are runnable.
    #
    read_waf_config()

    #
    # Add the proper prefix and suffix to the test-runner name to
    # match what is done in the wscript file.
    #
    test_runner_name = "%s%s-%s-%s" % (APPNAME, VERSION, "test-runner", BUILD_PROFILE)

    #
    # Run waf to make sure that everything is built, configured and ready to go
    # unless we are explicitly told not to.  We want to be careful about causing
    # our users pain while waiting for extraneous stuff to compile and link, so
    # we allow users that know what they''re doing to not invoke waf at all.
    #
    if not options.nowaf:

        #
        # If the user is running the "kinds" or "list" options, there is an 
        # implied dependency on the test-runner since we call that program
        # if those options are selected.  We will exit after processing those
        # options, so if we see them, we can safely only build the test-runner.
        #
        # If the user has constrained us to running only a particular type of
        # file, we can only ask waf to build what we know will be necessary.
        # For example, if the user only wants to run BVT tests, we only have
        # to build the test-runner and can ignore all of the examples.
        #
        # If the user only wants to run a single example, then we can just build
        # that example.
        #
        # If there is no constraint, then we have to build everything since the
        # user wants to run everything.
        #
        if options.kinds or options.list or (len(options.constrain) and options.constrain in core_kinds):
            if sys.platform == "win32":
                waf_cmd = "waf --target=test-runner"
            else:
                waf_cmd = "./waf --target=test-runner"
        elif len(options.example):
            if sys.platform == "win32":
                waf_cmd = "waf --target=%s" % os.path.basename(options.example)
            else:
                waf_cmd = "./waf --target=%s" % os.path.basename(options.example)

        else:
            if sys.platform == "win32":
                waf_cmd = "waf"
            else:
                waf_cmd = "./waf"

        if options.verbose:
            print "Building: %s" % waf_cmd

        proc = subprocess.Popen(waf_cmd, shell = True)
        proc.communicate()
        if proc.returncode:
            print >> sys.stderr, "Waf died. Not running tests"
            return proc.returncode

    #
    # Dynamically set up paths.
    #
    make_paths()

    #
    # Get the information from the build status file.
    #
    build_status_file = os.path.join (NS3_BUILDDIR, 'build-status.py')
    if os.path.exists(build_status_file):
        ns3_runnable_programs = get_list_from_file(build_status_file, "ns3_runnable_programs")
        ns3_runnable_scripts = get_list_from_file(build_status_file, "ns3_runnable_scripts")
    else:
        print >> sys.stderr, 'The build status file was not found.  You must do waf build before running test.py.'
        sys.exit(2)

    #
    # Make a dictionary that maps the name of a program to its path.
    #
    ns3_runnable_programs_dictionary = {}
    for program in ns3_runnable_programs:
        # Remove any directory names from path.
        program_name = os.path.basename(program)
        ns3_runnable_programs_dictionary[program_name] = program

    # Generate the lists of examples to run as smoke tests in order to
    # ensure that they remain buildable and runnable over time.
    #
    example_tests = []
    example_names_original = []
    python_tests = []
    for directory in EXAMPLE_DIRECTORIES:
        # Set the directories and paths for this example. 
        example_directory   = os.path.join("examples", directory)
        examples_to_run_path = os.path.join(example_directory, "examples-to-run.py")
        cpp_executable_dir   = os.path.join(NS3_BUILDDIR, example_directory)
        python_script_dir    = os.path.join(example_directory)

        # Parse this example directory's file.
        parse_examples_to_run_file(
            examples_to_run_path,
            cpp_executable_dir,
            python_script_dir,
            example_tests,
            example_names_original,
            python_tests)

    for module in NS3_ENABLED_MODULES:
        # Remove the "ns3-" from the module name.
        module = module[len("ns3-"):]

        # Set the directories and paths for this example. 
        module_directory     = os.path.join("src", module)
        example_directory    = os.path.join(module_directory, "examples")
        examples_to_run_path = os.path.join(module_directory, "test", "examples-to-run.py")
        cpp_executable_dir   = os.path.join(NS3_BUILDDIR, example_directory)
        python_script_dir    = os.path.join(example_directory)

        # Parse this module's file.
        parse_examples_to_run_file(
            examples_to_run_path,
            cpp_executable_dir,
            python_script_dir,
            example_tests,
            example_names_original,
            python_tests)

    #
    # If lots of logging is enabled, we can crash Python when it tries to 
    # save all of the text.  We just don't allow logging to be turned on when
    # test.py runs.  If you want to see logging output from your tests, you
    # have to run them using the test-runner directly.
    #
    os.environ["NS_LOG"] = ""

    #
    # There are a couple of options that imply we can to exit before starting
    # up a bunch of threads and running tests.  Let's detect these cases and 
    # handle them without doing all of the hard work.
    #
    if options.kinds:
        path_cmd = os.path.join("utils", test_runner_name + " --print-test-type-list")
        (rc, standard_out, standard_err, et) = run_job_synchronously(path_cmd, os.getcwd(), False, False)
        print standard_out

    if options.list:
        if len(options.constrain):
            path_cmd = os.path.join("utils", test_runner_name + " --print-test-name-list --print-test-types --test-type=%s" % options.constrain)
        else:
            path_cmd = os.path.join("utils", test_runner_name + " --print-test-name-list --print-test-types")
        (rc, standard_out, standard_err, et) = run_job_synchronously(path_cmd, os.getcwd(), False, False)
        list_items = standard_out.split('\n')
        list_items.sort()
        print "Test Type    Test Name"
        print "---------    ---------"
        for item in list_items:
            if len(item.strip()):
                print item
        example_names_original.sort()
        for item in example_names_original:
                print "example     ", item
        print

    if options.kinds or options.list:
        return

    #
    # We communicate results in two ways.  First, a simple message relating 
    # PASS, FAIL, CRASH or SKIP is always written to the standard output.  It 
    # is expected that this will be one of the main use cases.  A developer can
    # just run test.py with no options and see that all of the tests still 
    # pass.
    #
    # The second main use case is when detailed status is requested (with the
    # --text or --html options).  Typicall this will be text if a developer
    # finds a problem, or HTML for nightly builds.  In these cases, an
    # XML file is written containing the status messages from the test suites.
    # This file is then read and translated into text or HTML.  It is expected
    # that nobody will really be interested in the XML, so we write it somewhere
    # with a unique name (time) to avoid collisions.  In case an error happens, we
    # provide a runtime option to retain the temporary files.
    #
    # When we run examples as smoke tests, they are going to want to create
    # lots and lots of trace files.  We aren't really interested in the contents
    # of the trace files, so we also just stash them off in the temporary dir.
    # The retain option also causes these unchecked trace files to be kept.
    #
    date_and_time = time.strftime("%Y-%m-%d-%H-%M-%S-CUT", time.gmtime())

    if not os.path.exists(TMP_OUTPUT_DIR):
        os.makedirs(TMP_OUTPUT_DIR)

    testpy_output_dir = os.path.join(TMP_OUTPUT_DIR, date_and_time);

    if not os.path.exists(testpy_output_dir):
        os.makedirs(testpy_output_dir)

    #
    # Create the main output file and start filling it with XML.  We need to 
    # do this since the tests will just append individual results to this file.
    #
    xml_results_file = os.path.join(testpy_output_dir, "results.xml")
    f = open(xml_results_file, 'w')
    f.write('<?xml version="1.0"?>\n')
    f.write('<Results>\n')
    f.close()

    #
    # We need to figure out what test suites to execute.  We are either given one 
    # suite or example explicitly via the --suite or --example/--pyexample option,
    # or we need to call into the test runner and ask it to list all of the available
    # test suites.  Further, we need to provide the constraint information if it
    # has been given to us.
    # 
    # This translates into allowing the following options with respect to the 
    # suites
    #
    #  ./test,py:                                           run all of the suites and examples
    #  ./test.py --constrain=core:                          run all of the suites of all kinds
    #  ./test.py --constrain=unit:                          run all unit suites
    #  ./test.py --suite=some-test-suite:                   run a single suite
    #  ./test.py --example=examples/udp/udp-echo:           run single example
    #  ./test.py --pyexample=examples/wireless/mixed-wireless.py:  run python example
    #  ./test.py --suite=some-suite --example=some-example: run the single suite
    #
    # We can also use the --constrain option to provide an ordering of test 
    # execution quite easily.
    #
    if len(options.suite):
        # See if this is a valid test suite.
        path_cmd = os.path.join("utils", test_runner_name + " --print-test-name-list")
        (rc, suites, standard_err, et) = run_job_synchronously(path_cmd, os.getcwd(), False, False)
        if options.suite in suites.split('\n'):
            suites = options.suite + "\n"
        else:
            print >> sys.stderr, 'The test suite was not run because an unknown test suite name was requested.'
            sys.exit(2)

    elif len(options.example) == 0 and len(options.pyexample) == 0:
        if len(options.constrain):
            path_cmd = os.path.join("utils", test_runner_name + " --print-test-name-list --test-type=%s" % options.constrain)
            (rc, suites, standard_err, et) = run_job_synchronously(path_cmd, os.getcwd(), False, False)
        else:
            path_cmd = os.path.join("utils", test_runner_name + " --print-test-name-list")
            (rc, suites, standard_err, et) = run_job_synchronously(path_cmd, os.getcwd(), False, False)
    else:
        suites = ""

    #
    # suite_list will either a single test suite name that the user has 
    # indicated she wants to run or a list of test suites provided by
    # the test-runner possibly according to user provided constraints.
    # We go through the trouble of setting up the parallel execution 
    # even in the case of a single suite to avoid having two process the
    # results in two different places.
    #
    suite_list = suites.split('\n')

    #
    # Performance tests should only be run when they are requested,
    # i.e. they are not run by default in test.py.
    #
    if options.constrain != 'performance':

        # Get a list of all of the performance tests.
        path_cmd = os.path.join("utils", test_runner_name + " --print-test-name-list --test-type=%s" % "performance")
        (rc, performance_tests, standard_err, et) = run_job_synchronously(path_cmd, os.getcwd(), False, False)
        performance_test_list = performance_tests.split('\n')

        # Remove any performance tests from the suites list.
        for performance_test in performance_test_list:
            if performance_test in suite_list:
                suite_list.remove(performance_test)

    # We now have a possibly large number of test suites to run, so we want to
    # run them in parallel.  We're going to spin up a number of worker threads
    # that will run our test jobs for us.
    #
    input_queue = Queue.Queue(0)
    output_queue = Queue.Queue(0)

    jobs = 0
    threads=[]

    #
    # In Python 2.6 you can just use multiprocessing module, but we don't want
    # to introduce that dependency yet; so we jump through a few hoops.
    #
    processors = 1

    if sys.platform != "win32":
        if 'SC_NPROCESSORS_ONLN'in os.sysconf_names:
            processors = os.sysconf('SC_NPROCESSORS_ONLN')
        else:
            proc = subprocess.Popen("sysctl -n hw.ncpu", shell = True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
            stdout_results, stderr_results = proc.communicate()
            if len(stderr_results) == 0:
                processors = int(stdout_results)

    #
    # Now, spin up one thread per processor which will eventually mean one test
    # per processor running concurrently.
    #
    for i in range(processors):
        thread = worker_thread(input_queue, output_queue)
        threads.append(thread)
        thread.start()

    #
    # Keep track of some summary statistics
    #
    total_tests = 0
    skipped_tests = 0

    #
    # We now have worker threads spun up, and a list of work to do.  So, run 
    # through the list of test suites and dispatch a job to run each one.
    # 
    # Dispatching will run with unlimited speed and the worker threads will 
    # execute as fast as possible from the queue.
    #
    # Note that we actually dispatch tests to be skipped, so all of the 
    # PASS, FAIL, CRASH and SKIP processing is done in the same place.
    #
    for test in suite_list:
        test = test.strip()
        if len(test):
            job = Job()
            job.set_is_example(False)
            job.set_is_pyexample(False)
            job.set_display_name(test)
            job.set_tmp_file_name(os.path.join(testpy_output_dir, "%s.xml" % test))
            job.set_cwd(os.getcwd())
            job.set_basedir(os.getcwd())
            job.set_tempdir(testpy_output_dir)
            if (options.multiple):
                multiple = ""
            else:
                multiple = " --stop-on-failure"
            if (len(options.fullness)):
                fullness = options.fullness.upper()
                fullness = " --fullness=%s" % fullness
            else:
                fullness = " --fullness=QUICK"

            path_cmd = os.path.join("utils", test_runner_name + " --test-name=%s%s%s" % (test, multiple, fullness))

            job.set_shell_command(path_cmd)

            if options.valgrind and test in core_valgrind_skip_tests:
                job.set_is_skip(True)

            # Skip tests that will fail if NSC is missing.
            if not NSC_ENABLED and test in core_nsc_missing_skip_tests:
                job.set_is_skip(True)

            if options.verbose:
                print "Queue %s" % test

            input_queue.put(job)
            jobs = jobs + 1
            total_tests = total_tests + 1
    
    #
    # We've taken care of the discovered or specified test suites.  Now we
    # have to deal with examples run as smoke tests.  We have a list of all of
    # the example programs it makes sense to try and run.  Each example will
    # have a condition associated with it that must evaluate to true for us
    # to try and execute it.  This is used to determine if the example has
    # a dependency that is not satisfied.  For example, if an example depends
    # on NSC being configured by waf, that example should have a condition
    # that evaluates to true if NSC is enabled.  For example,
    #
    #      ("tcp-nsc-zoo", "NSC_ENABLED == True"),
    #
    # In this case, the example "tcp-nsc-zoo" will only be run if we find the
    # waf configuration variable "NSC_ENABLED" to be True.
    #
    # We don't care at all how the trace files come out, so we just write them 
    # to a single temporary directory.
    #
    # XXX As it stands, all of the trace files have unique names, and so file
    # collisions can only happen if two instances of an example are running in
    # two versions of the test.py process concurrently.  We may want to create
    # uniquely named temporary traces directories to avoid this problem.
    #
    # We need to figure out what examples to execute.  We are either given one 
    # suite or example explicitly via the --suite or --example option, or we
    # need to walk the list of examples looking for available example 
    # conditions.
    #
    # This translates into allowing the following options with respect to the 
    # suites
    #
    #  ./test.py:                                           run all of the examples
    #  ./test.py --constrain=unit                           run no examples
    #  ./test.py --constrain=example                        run all of the examples
    #  ./test.py --suite=some-test-suite:                   run no examples
    #  ./test.py --example=some-example:                    run the single example
    #  ./test.py --suite=some-suite --example=some-example: run the single example
    #
    #
    if len(options.suite) == 0 and len(options.example) == 0 and len(options.pyexample) == 0:
        if len(options.constrain) == 0 or options.constrain == "example":
            if ENABLE_EXAMPLES:
                for test, do_run, do_valgrind_run in example_tests:
                    # Remove any arguments and directory names from test.
                    test_name = test.split(' ', 1)[0] 
                    test_name = os.path.basename(test_name)

                    # Don't try to run this example if it isn't runnable.
                    if ns3_runnable_programs_dictionary.has_key(test_name):
                        if eval(do_run):
                            job = Job()
                            job.set_is_example(True)
                            job.set_is_pyexample(False)
                            job.set_display_name(test)
                            job.set_tmp_file_name("")
                            job.set_cwd(testpy_output_dir)
                            job.set_basedir(os.getcwd())
                            job.set_tempdir(testpy_output_dir)
                            job.set_shell_command(test)
                            job.set_build_path(options.buildpath)

                            if options.valgrind and not eval(do_valgrind_run):
                                job.set_is_skip (True)

                            if options.verbose:
                                print "Queue %s" % test

                            input_queue.put(job)
                            jobs = jobs + 1
                            total_tests = total_tests + 1

    elif len(options.example):
        # Add the proper prefix and suffix to the example name to
        # match what is done in the wscript file.
        example_name = "%s%s-%s-%s" % (APPNAME, VERSION, options.example, BUILD_PROFILE)

        # Don't try to run this example if it isn't runnable.
        if not ns3_runnable_programs_dictionary.has_key(example_name):
            print "Example %s is not runnable." % example_name
        else:
            #
            # If you tell me to run an example, I will try and run the example
            # irrespective of any condition.
            #
            example_path = ns3_runnable_programs_dictionary[example_name]
            job = Job()
            job.set_is_example(True)
            job.set_is_pyexample(False)
            job.set_display_name(example_path)
            job.set_tmp_file_name("")
            job.set_cwd(testpy_output_dir)
            job.set_basedir(os.getcwd())
            job.set_tempdir(testpy_output_dir)
            job.set_shell_command(example_path)
            job.set_build_path(options.buildpath)

            if options.verbose:
                print "Queue %s" % example_name

            input_queue.put(job)
            jobs = jobs + 1
            total_tests = total_tests + 1

    #
    # Run some Python examples as smoke tests.  We have a list of all of
    # the example programs it makes sense to try and run.  Each example will
    # have a condition associated with it that must evaluate to true for us
    # to try and execute it.  This is used to determine if the example has
    # a dependency that is not satisfied.
    #
    # We don't care at all how the trace files come out, so we just write them 
    # to a single temporary directory.
    #
    # We need to figure out what python examples to execute.  We are either 
    # given one pyexample explicitly via the --pyexample option, or we
    # need to walk the list of python examples
    #
    # This translates into allowing the following options with respect to the 
    # suites
    #
    #  ./test.py --constrain=pyexample           run all of the python examples
    #  ./test.py --pyexample=some-example.py:    run the single python example
    #
    if len(options.suite) == 0 and len(options.example) == 0 and len(options.pyexample) == 0:
        if len(options.constrain) == 0 or options.constrain == "pyexample":
            if ENABLE_EXAMPLES:
                for test, do_run in python_tests:
                    # Remove any arguments and directory names from test.
                    test_name = test.split(' ', 1)[0] 
                    test_name = os.path.basename(test_name)

                    # Don't try to run this example if it isn't runnable.
                    if test_name in ns3_runnable_scripts:
                        if eval(do_run):
                            job = Job()
                            job.set_is_example(False)
                            job.set_is_pyexample(True)
                            job.set_display_name(test)
                            job.set_tmp_file_name("")
                            job.set_cwd(testpy_output_dir)
                            job.set_basedir(os.getcwd())
                            job.set_tempdir(testpy_output_dir)
                            job.set_shell_command(test)
                            job.set_build_path("")

                            #
                            # Python programs and valgrind do not work and play
                            # well together, so we skip them under valgrind.
                            # We go through the trouble of doing all of this
                            # work to report the skipped tests in a consistent
                            # way throught the output formatter.
                            #
                            if options.valgrind:
                                job.set_is_skip (True)

                            #
                            # The user can disable python bindings, so we need
                            # to pay attention to that and give some feedback
                            # that we're not testing them
                            #
                            if not ENABLE_PYTHON_BINDINGS:
                                job.set_is_skip (True)

                            if options.verbose:
                                print "Queue %s" % test

                            input_queue.put(job)
                            jobs = jobs + 1
                            total_tests = total_tests + 1

    elif len(options.pyexample):
        # Don't try to run this example if it isn't runnable.
        example_name = os.path.basename(options.pyexample)
        if example_name not in ns3_runnable_scripts:
            print "Example %s is not runnable." % example_name
        else:
            #
            # If you tell me to run a python example, I will try and run the example
            # irrespective of any condition.
            #
            job = Job()
            job.set_is_pyexample(True)
            job.set_display_name(options.pyexample)
            job.set_tmp_file_name("")
            job.set_cwd(testpy_output_dir)
            job.set_basedir(os.getcwd())
            job.set_tempdir(testpy_output_dir)
            job.set_shell_command(options.pyexample)
            job.set_build_path("")

            if options.verbose:
                print "Queue %s" % options.pyexample

            input_queue.put(job)
            jobs = jobs + 1
            total_tests = total_tests + 1

    #
    # Tell the worker threads to pack up and go home for the day.  Each one
    # will exit when they see their is_break task.
    #
    for i in range(processors):
        job = Job()
        job.set_is_break(True)
        input_queue.put(job)

    #
    # Now all of the tests have been dispatched, so all we have to do here
    # in the main thread is to wait for them to complete.  Keyboard interrupt
    # handling is broken as mentioned above.  We use a signal handler to catch
    # sigint and set a global variable.  When the worker threads sense this
    # they stop doing real work and will just start throwing jobs back at us
    # with is_break set to True.  In this case, there are no real results so we 
    # ignore them.  If there are real results, we always print PASS or FAIL to
    # standard out as a quick indication of what happened.
    #
    passed_tests = 0
    failed_tests = 0
    crashed_tests = 0
    valgrind_errors = 0
    for i in range(jobs):
        job = output_queue.get()
        if job.is_break:
            continue

        if job.is_example or job.is_pyexample:
            kind = "Example"
        else:
            kind = "TestSuite"

        if job.is_skip:
            status = "SKIP"
            skipped_tests = skipped_tests + 1
        else:
            if job.returncode == 0:
                status = "PASS"
                passed_tests = passed_tests + 1
            elif job.returncode == 1:
                failed_tests = failed_tests + 1
                status = "FAIL"
            elif job.returncode == 2:
                valgrind_errors = valgrind_errors + 1
                status = "VALGR"
            else:
                crashed_tests = crashed_tests + 1
                status = "CRASH"

        if options.duration or options.constrain == "performance":
            print "%s (%.3f): %s %s" % (status, job.elapsed_time, kind, job.display_name)
        else:
            print "%s: %s %s" % (status, kind, job.display_name)

        if job.is_example or job.is_pyexample:
            #
            # Examples are the odd man out here.  They are written without any
            # knowledge that they are going to be run as a test, so we need to 
            # cook up some kind of output for them.  We're writing an xml file,
            # so we do some simple XML that says we ran the example.
            #
            # XXX We could add some timing information to the examples, i.e. run
            # them through time and print the results here.
            #
            f = open(xml_results_file, 'a')
            f.write('<Example>\n')
            example_name = "  <Name>%s</Name>\n" % job.display_name
            f.write(example_name)

            if status == "PASS":
                f.write('  <Result>PASS</Result>\n')
            elif status == "FAIL":
                f.write('  <Result>FAIL</Result>\n')
            elif status == "VALGR":
                f.write('  <Result>VALGR</Result>\n')
            elif status == "SKIP":
                f.write('  <Result>SKIP</Result>\n')
            else:
                f.write('  <Result>CRASH</Result>\n')

            f.write('  <Time real="%.3f"/>\n' % job.elapsed_time)
            f.write('</Example>\n')
            f.close()

        else:
            #
            # If we're not running an example, we're running a test suite.
            # These puppies are running concurrently and generating output
            # that was written to a temporary file to avoid collisions.
            #
            # Now that we are executing sequentially in the main thread, we can
            # concatenate the contents of the associated temp file to the main 
            # results file and remove that temp file.
            #
            # One thing to consider is that a test suite can crash just as
            # well as any other program, so we need to deal with that 
            # possibility as well.  If it ran correctly it will return 0
            # if it passed, or 1 if it failed.  In this case, we can count
            # on the results file it saved being complete.  If it crashed, it 
            # will return some other code, and the file should be considered 
            # corrupt and useless.  If the suite didn't create any XML, then
            # we're going to have to do it ourselves.
            #
            # Another issue is how to deal with a valgrind error.  If we run
            # a test suite under valgrind and it passes, we will get a return
            # code of 0 and there will be a valid xml results file since the code
            # ran to completion.  If we get a return code of 1 under valgrind,
            # the test case failed, but valgrind did not find any problems so the
            # test case return code was passed through.  We will have a valid xml
            # results file here as well since the test suite ran.  If we see a 
            # return code of 2, this means that valgrind found an error (we asked
            # it to return 2 if it found a problem in run_job_synchronously) but
            # the suite ran to completion so there is a valid xml results file.
            # If the suite crashes under valgrind we will see some other error 
            # return code (like 139).  If valgrind finds an illegal instruction or
            # some other strange problem, it will die with its own strange return
            # code (like 132).  However, if the test crashes by itself, not under
            # valgrind we will also see some other return code.
            #
            # If the return code is 0, 1, or 2, we have a valid xml file.  If we 
            # get another return code, we have no xml and we can't really say what
            # happened -- maybe the TestSuite crashed, maybe valgrind crashed due
            # to an illegal instruction.  If we get something beside 0-2, we assume
            # a crash and fake up an xml entry.  After this is all done, we still
            # need to indicate a valgrind error somehow, so we fake up an xml entry
            # with a VALGR result.  Thus, in the case of a working TestSuite that
            # fails valgrind, we'll see the PASS entry for the working TestSuite
            # followed by a VALGR failing test suite of the same name.
            #
            if job.is_skip:
                f = open(xml_results_file, 'a')
                f.write("<Test>\n")
                f.write("  <Name>%s</Name>\n" % job.display_name)
                f.write('  <Result>SKIP</Result>\n')
                f.write("</Test>\n")
                f.close()
            else:
                if job.returncode == 0 or job.returncode == 1 or job.returncode == 2:
                    f_to = open(xml_results_file, 'a')
                    f_from = open(job.tmp_file_name)
                    f_to.write(f_from.read())
                    f_to.close()
                    f_from.close()
                else:
                    f = open(xml_results_file, 'a')
                    f.write("<Test>\n")
                    f.write("  <Name>%s</Name>\n" % job.display_name)
                    f.write('  <Result>CRASH</Suite>\n')
                    f.write("</Test>\n")
                    f.close()

                    if job.returncode == 2:
                        f = open(xml_results_file, 'a')
                        f.write("<Test>\n")
                        f.write("  <Name>%s</Name>\n" % job.display_name)
                        f.write('  <Result>VALGR</Result>\n')
                        f.write("</Test>\n")
                        f.close()

    #
    # We have all of the tests run and the results written out.  One final 
    # bit of housekeeping is to wait for all of the threads to close down
    # so we can exit gracefully.
    #
    for thread in threads:
        thread.join()
    
    #
    # Back at the beginning of time, we started the body of an XML document
    # since the test suites and examples were going to just write their 
    # individual pieces.  So, we need to finish off and close out the XML 
    # document
    #
    f = open(xml_results_file, 'a')
    f.write('</Results>\n')
    f.close()

    #
    # Print a quick summary of events
    #
    print "%d of %d tests passed (%d passed, %d skipped, %d failed, %d crashed, %d valgrind errors)" % (passed_tests, 
        total_tests, passed_tests, skipped_tests, failed_tests, crashed_tests, valgrind_errors)
    #
    # The last things to do are to translate the XML results file to "human
    # readable form" if the user asked for it (or make an XML file somewhere)
    #
    if len(options.html):
        translate_to_html(xml_results_file, options.html)

    if len(options.text):
        translate_to_text(xml_results_file, options.text)

    if len(options.xml):
        shutil.copyfile(xml_results_file, options.xml)

    #
    # Let the user know if they need to turn on tests or examples.
    #
    if not ENABLE_TESTS or not ENABLE_EXAMPLES:
        print
        if not ENABLE_TESTS:
            print '***  Note: ns-3 tests are currently disabled. Enable them by adding'
            print '***  "--enable-tests" to ./waf configure or modifying your .ns3rc file.'
            print
        if not ENABLE_EXAMPLES:
            print '***  Note: ns-3 examples are currently disabled. Enable them by adding'
            print '***  "--enable-examples" to ./waf configure or modifying your .ns3rc file.'
            print
    #
    # If we have been asked to retain all of the little temporary files, we
    # don't delete tm.  If we do delete the temporary files, delete only the
    # directory we just created.  We don't want to happily delete any retained
    # directories, which will probably surprise the user.
    #
    if not options.retain:
        shutil.rmtree(testpy_output_dir)

    if passed_tests + skipped_tests == total_tests:
        return 0 # success
    else:
        return 1 # catchall for general errors

def main(argv):
    parser = optparse.OptionParser()
    parser.add_option("-b", "--buildpath", action="store", type="string", dest="buildpath", default="",
                      metavar="BUILDPATH",
                      help="specify the path where ns-3 was built (defaults to the build directory for the current variant)")

    parser.add_option("-c", "--constrain", action="store", type="string", dest="constrain", default="",
                      metavar="KIND",
                      help="constrain the test-runner by kind of test")

    parser.add_option("-d", "--duration", action="store_true", dest="duration", default=False,
                      help="print the duration of each test suite and example")

    parser.add_option("-e", "--example", action="store", type="string", dest="example", default="",
                      metavar="EXAMPLE",
                      help="specify a single example to run (no relative path is needed)")

    parser.add_option("-u", "--update-data", action="store_true", dest="update_data", default=False,
                      help="If examples use reference data files, get them to re-generate them")

    parser.add_option("-f", "--fullness", action="store", type="string", dest="fullness", default="QUICK",
                      metavar="FULLNESS",
                      help="choose the duration of tests to run: QUICK, EXTENSIVE, or TAKES_FOREVER, where EXTENSIVE includes QUICK and TAKES_FOREVER includes QUICK and EXTENSIVE (only QUICK tests are run by default)")

    parser.add_option("-g", "--grind", action="store_true", dest="valgrind", default=False,
                      help="run the test suites and examples using valgrind")

    parser.add_option("-k", "--kinds", action="store_true", dest="kinds", default=False,
                      help="print the kinds of tests available")

    parser.add_option("-l", "--list", action="store_true", dest="list", default=False,
                      help="print the list of known tests")

    parser.add_option("-m", "--multiple", action="store_true", dest="multiple", default=False,
                      help="report multiple failures from test suites and test cases")

    parser.add_option("-n", "--nowaf", action="store_true", dest="nowaf", default=False,
                      help="do not run waf before starting testing")

    parser.add_option("-p", "--pyexample", action="store", type="string", dest="pyexample", default="",
                      metavar="PYEXAMPLE",
                      help="specify a single python example to run (with relative path)")

    parser.add_option("-r", "--retain", action="store_true", dest="retain", default=False,
                      help="retain all temporary files (which are normally deleted)")

    parser.add_option("-s", "--suite", action="store", type="string", dest="suite", default="",
                      metavar="TEST-SUITE",
                      help="specify a single test suite to run")

    parser.add_option("-t", "--text", action="store", type="string", dest="text", default="",
                      metavar="TEXT-FILE",
                      help="write detailed test results into TEXT-FILE.txt")

    parser.add_option("-v", "--verbose", action="store_true", dest="verbose", default=False,
                      help="print progress and informational messages")

    parser.add_option("-w", "--web", "--html", action="store", type="string", dest="html", default="",
                      metavar="HTML-FILE",
                      help="write detailed test results into HTML-FILE.html")

    parser.add_option("-x", "--xml", action="store", type="string", dest="xml", default="",
                      metavar="XML-FILE",
                      help="write detailed test results into XML-FILE.xml")

    global options
    options = parser.parse_args()[0]
    signal.signal(signal.SIGINT, sigint_hook)

    return run_tests()

if __name__ == '__main__':
    sys.exit(main(sys.argv))
