Put the `mojo_test` test list format in the command line description.

mojo/devtools/common/mojo_test

 #!/usr/bin/env python
 # Copyright 2015 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Test runner for Mojo application tests.
 
-The file describing the list of tests has to be a valid Python program that sets
-a |tests| global variable, containing entries of the following form:
+TODO(vtl|msw): Add a way of specifying data dependencies.

[ppi, 2015/07/29 13:38:43]

here.

+"""
+
+import argparse
+import logging
+import sys
+
+from devtoolslib import apptest_dart
+from devtoolslib import apptest_gtest
+from devtoolslib import shell_arguments
+
+_DESCRIPTION = """Runner for Mojo application tests.
+
+|test_list_file| has to be a valid Python program that sets a |tests| global
+variable, containing entries of the following form:
 
  {
    # Required URL for apptest.
    "test": "mojo:test_app_url",
    # Optional display name (otherwise the entry for "test" above is used).
    "name": "mojo:test_app_url (more details)",
    # Optional test type. Valid values:
    #   * "gtest" (default)
    #   * "gtest_isolated": like "gtest", but run with fixture isolation,
-   #      i.e., each test in a fresh mojo_shell)
-   #   * "dart".
+   #      i.e., each test in a fresh mojo_shell
+   #   * "dart"
    "type": "gtest",
-   # Optional arguments for the apptest.
+   # Optional arguments to be passed to the apptest.
    "test-args": ["--an_arg", "another_arg"],
-   # Optional arguments for the shell.
+   # Optional shell arguments.
    "shell-args": ["--some-flag-for-the-shell", "--another-flag"],
  }
 
-The program may use the |target_os| global that will be any of ['android',
-'linux'], indicating the system on which the tests are to be run.
-
-TODO(vtl|msw): Add a way of specifying data dependencies.

[qsr, 2015/07/29 13:37:57]

Where is this todo gone?

-"""
-
-_DESCRIPTION = """Runner for Mojo application tests.
+|test_list_file| may reference the |target_os| global that will be any of
+['android', 'linux'], indicating the system on which the tests are to be run.
 
 Any arguments not recognized by the script will be passed on as shell arguments.
 """
 
-import argparse
-import logging
-import sys
-
-from devtoolslib import apptest_dart
-from devtoolslib import apptest_gtest
-from devtoolslib import shell_arguments
-
 _logger = logging.getLogger()
 
 
 def main():
-  parser = argparse.ArgumentParser(description=_DESCRIPTION)
+  parser = argparse.ArgumentParser(
+      formatter_class=argparse.RawDescriptionHelpFormatter,
+      description=_DESCRIPTION)
   parser.add_argument("test_list_file", type=file,
                       help="a file listing apptests to run")
 
   # Common shell configuration arguments.
   shell_arguments.add_shell_arguments(parser)
   script_args, common_shell_args = parser.parse_known_args()
 
   try:
     shell, common_shell_args = shell_arguments.configure_shell(
         script_args, common_shell_args)
@@ skipping 32 matching lines @@
       print "Unrecognized test type in %r" % test_dict
 
     print "Succeeded" if apptest_result else "Failed"
     _logger.info("Completed: %s" % test_name)
     if not apptest_result:
       succeeded = False
   return 0 if succeeded else 1
 
 if __name__ == '__main__':
   sys.exit(main())