Minor loader improvements.

recipe_engine/unittests/loader_test.py

 #!/usr/bin/env python
 # Copyright 2015 The LUCI Authors. All rights reserved.
 # Use of this source code is governed under the Apache License, Version 2.0
 # that can be found in the LICENSE file.
 
 import unittest
 
 import test_env
 
 from recipe_engine import loader, recipe_api, config
 import mock
 
 
 class TestRecipeScript(unittest.TestCase):
   def testReturnSchemaHasValidClass(self):
-    with self.assertRaises(ValueError):
-      loader.RecipeScript('fake_recipe',
-                          {'RETURN_SCHEMA': 3}, 'fake_package', 'some/path')
+    with self.assertRaises(loader.MalformedRecipeError):
+      loader.RecipeScript('fake_recipe', {
+        'GenTests': lambda api: None,
+        'RunSteps': lambda api: None,
+        'RETURN_SCHEMA': 3,
+      }, 'fake_package', 'some/path')
 
   def testRunChecksReturnType(self):
     sentinel = object()
     mocked_return = object()
     class FakeReturn(object):
       def as_jsonish(_self, hidden=sentinel):
         self.assertEqual(True, hidden)
 
         return mocked_return
 
     script = loader.RecipeScript(
       'fake_recipe', {
         'RETURN_SCHEMA': config.ConfigGroupSchema(a=config.Single(int)),
-        'RunSteps': None,
+        'RunSteps': lambda api: None,
+        'GenTests': lambda api: None,
       }, 'fake_package', 'some/path')
     loader.invoke_with_properties = lambda *args, **kwargs: FakeReturn()
 
     self.assertEqual(mocked_return, script.run(None, None))
 
 def make_prop(**kwargs):
   name = kwargs.pop('name', "dumb_name")
   return recipe_api.Property(**kwargs).bind(
     name, recipe_api.BoundProperty.RECIPE_PROPERTY,
     'fake_package::fake_recipe')
@@ skipping 92 matching lines @@
 
     with mock.patch(
         'recipe_engine.loader._invoke_with_properties') as mocked_invoke:
       loader.invoke_with_properties(TestClass, None, None)
       args, _ = mocked_invoke.call_args
       self.assertTrue(['api', 'foo', 'bar'] in args)
 
 
 if __name__ == '__main__':
   unittest.main()