Minor loader improvements.

unittests/errors_test.py

 #!/usr/bin/env python
 # Copyright 2014 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 json
 import os
 import shutil
 import subprocess
 import tempfile
@@ skipping 275 matching lines @@
   def test_engine_failure(self):
     with RecipeRepo() as repo:
       repo.make_recipe('print_step_error', """
 DEPS = ['recipe_engine/step']
 
 from recipe_engine import step_runner
 
 def bad_print_step(self, step_stream, step, env):
   raise Exception("Buh buh buh buh bad to the bone")
 
+def GenTests(api):
+  pass
+
 def RunSteps(api):
   step_runner.SubprocessStepRunner._print_step = bad_print_step
   try:
     api.step('Be good', ['echo', 'Sunshine, lollipops, and rainbows'])
   finally:
     api.step.active_result.presentation.status = 'WARNING'
 """)
       self._test_cmd(repo, ['run', 'print_step_error'],
         asserts=lambda stdout, stderr: self.assertRegexpMatches(
             stdout + stderr,
             r'(?s)Recipe engine bug.*Buh buh buh buh bad to the bone'),
         retcode=2)
 
+  def test_missing_method(self):
+    with RecipeRepo() as repo:
+      repo.make_recipe('no_gen_tests', """
+def RunSteps(api):
+  pass
+""")
+      repo.make_recipe('no_run_steps', """
+def GenTests(api):
+  pass
+""")
+
+      self._test_cmd(repo, ['run', 'no_gen_tests'],
+        asserts=lambda stdout, stderr: self.assertRegexpMatches(
+            stdout + stderr,
+            r'(?s)misspelled GenTests'),
+        retcode=2)
+
+      self._test_cmd(repo, ['run', 'no_run_steps'],
+        asserts=lambda stdout, stderr: self.assertRegexpMatches(
+            stdout + stderr,
+            r'(?s)misspelled RunSteps'),
+        retcode=2)
+
   def test_unconsumed_assertion(self):
     # There was a regression where unconsumed exceptions would not be detected
     # if the exception was AssertionError.
 
     with RecipeRepo() as repo:
       repo.make_recipe('unconsumed_assertion', """
 DEPS = []
 
 def RunSteps(api):
   pass
@@ skipping 21 matching lines @@
           stdout, r'from the root of a \'testproj\' checkout')
       self.assertRegexpMatches(
           stdout, r'\./foo/bar/recipes\.py run .* do_nothing')
 
 
 
 
 
 if __name__ == '__main__':
   unittest.main()