Fix error code propagation in 'mb gen'.

tools/mb/mb_unittest.py

 # 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.
 
 """Tests for mb.py."""
 
 import json
 import sys
 import unittest
 
@@ skipping 82 matching lines @@
       'gn_args': 'is_debug=true',
     },
   },
   'private_configs': ['private'],
   'unsupported_configs': ['unsupported'],
 }
 """
 
 
 class UnitTest(unittest.TestCase):
-  def fake_mbw(self, files):
+  def fake_mbw(self, files=None):
     mbw = FakeMBW()
+    mbw.files.setdefault(mbw.default_config, TEST_CONFIG)

[Dirk Pranke, 2015/04/24 20:38:52]

these diffs are unrelated to the fix, but clean up the api a bit.

     if files:
       for path, contents in files.items():
         mbw.files[path] = contents
-    mbw.files.setdefault(mbw.default_config, TEST_CONFIG)
     return mbw
 
   def check(self, args, mbw=None, files=None, out=None, err=None, ret=None):
     if not mbw:
       mbw = self.fake_mbw(files)
     mbw.ParseArgs(args)
     actual_ret = mbw.args.func()
     if ret is not None:
       self.assertEqual(actual_ret, ret)
     if out is not None:
@@ skipping 54 matching lines @@
 
   def test_gyp_analyze(self):
     self.check(['analyze', '-c', 'gyp_rel_bot', '//out/Release',
                 '/tmp/in.json', '/tmp/out.json'],
                ret=0)
 
   def test_gen(self):
     self.check(['gen', '-c', 'gn_debug', '//out/Default'], ret=0)
     self.check(['gen', '-c', 'gyp_rel_bot', '//out/Release'], ret=0)
 
+  def test_gen_fails(self):
+    mbw = self.fake_mbw()
+    mbw.Call = lambda cmd: (1, '', '')
+    self.check(['gen', '-c', 'gn_debug', '//out/Default'], mbw=mbw, ret=1)
+    self.check(['gen', '-c', 'gyp_rel_bot', '//out/Release'], mbw=mbw, ret=1)
+
   def test_goma_dir_expansion(self):
     self.check(['lookup', '-c', 'gyp_rel_bot', '-g', '/foo'], ret=0,
                out=("python build/gyp_chromium -G 'output_dir=<path>' "
                     "-G config=Release -D goma=1 -D gomadir=/foo\n"))
     self.check(['lookup', '-c', 'gn_rel_bot', '-g', '/foo'], ret=0,
                out=("/fake_src/buildtools/linux64/gn gen '<path>' "
                     "'--args=is_debug=false use_goma=true "
                     "goma_dir=\"/foo\"'\n" ))
 
   def test_help(self):
     self.assertRaises(SystemExit, self.check, ['-h'])
     self.assertRaises(SystemExit, self.check, ['help'])
     self.assertRaises(SystemExit, self.check, ['help', 'gen'])
 
   def test_lookup(self):
     self.check(['lookup', '-c', 'gn_debug'], ret=0)
 
   def test_validate(self):
     self.check(['validate'], ret=0)
 
 
 if __name__ == '__main__':
   unittest.main()