Add module discovery and autoloading to expect_tests.

scripts/slave/unittests/recipe_simulation_test.py

 #!/usr/bin/env python
 # Copyright 2014 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.
 
 """Provides simulator test coverage for individual recipes."""
 
 import logging
 import os
 
@@ skipping 44 matching lines @@
   return expect_tests.Result(ret)
 
 
 def test_gen_coverage():
   return (
       [os.path.join(x, '*') for x in recipe_util.RECIPE_DIRS()] +
       [os.path.join(x, '*', 'example.py') for x in recipe_util.MODULE_DIRS()] +
       [os.path.join(x, '*', 'test_api.py') for x in recipe_util.MODULE_DIRS()]
   )
 
+@expect_tests.test_generator
 @expect_tests.covers(test_gen_coverage)
 def GenerateTests():
   cover_mods = []
   for mod_dir_base in recipe_util.MODULE_DIRS():
     if os.path.isdir(mod_dir_base):
       cover_mods.append(os.path.join(mod_dir_base, '*', '*api.py'))
 
   for recipe_path, recipe_name in recipe_loader.loop_over_recipes():
     recipe = recipe_loader.load_recipe(recipe_name)
     test_api = recipe_loader.create_test_api(recipe.DEPS)
@@ skipping 19 matching lines @@
 if __name__ == '__main__':
   # annotated_run.py has different behavior when these environment variables
   # are set, so unset to make simulation tests environment-invariant.
   for env_var in ['TESTING_MASTER_HOST',
                   'TESTING_MASTER',
                   'TESTING_SLAVENAME']:
     if env_var in os.environ:
       logging.warn("Ignoring %s environment variable." % env_var)
       os.environ.pop(env_var)
 
-  expect_tests.main('recipe_simulation_test', GenerateTests)
+  expect_tests.main()