Support references to args files in MB.

tools/mb/mb_unittest.py

 #!/usr/bin/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.
 
 """Tests for mb.py."""
 
 import json
 import StringIO
 import os
@@ skipping 100 matching lines @@
     'gyp_crosscompile': ['gyp', 'crosscompile'],
   },
   'masters': {
     'chromium': {},
     'fake_master': {
       'fake_builder': 'gyp_rel_bot',
       'fake_gn_builder': 'gn_rel_bot',
       'fake_gyp_crosscompile_builder': 'gyp_crosscompile',
       'fake_gn_debug_builder': 'gn_debug_goma',
       'fake_gyp_builder': 'gyp_debug',
+      'fake_gn_args_bot': '//build/args/bots/fake_master/fake_gn_args_bot.gn',
     },
   },
   'mixins': {
     'crosscompile': {
       'gyp_crosscompile': True,
     },
     'fake_feature1': {
       'gn_args': 'enable_doom_melon=true',
       'gyp_defines': 'doom_melon=1',
     },
@@ skipping 38 matching lines @@
       'gn_args': 'is_debug=false',
     },
   },
 }
 """
 
 class UnitTest(unittest.TestCase):
   def fake_mbw(self, files=None, win32=False):
     mbw = FakeMBW(win32=win32)
     mbw.files.setdefault(mbw.default_config, TEST_CONFIG)
+    mbw.files.setdefault(
+        mbw.ToAbsPath('//build/args/bots/fake_master/fake_gn_args_bot.gn'),
+        'is_debug = false\n')
     if files:
       for path, contents in files.items():
         mbw.files[path] = contents
     return mbw
 
   def check(self, args, mbw=None, files=None, out=None, err=None, ret=None):
     if not mbw:
       mbw = self.fake_mbw(files)
 
     actual_ret = mbw.Main(args)
@@ skipping 123 matching lines @@
     mbw = self.fake_mbw(win32=True)
     self.check(['gen', '-c', 'gn_debug_goma', '-g', 'c:\\goma', '//out/Debug'],
                mbw=mbw, ret=0,
                out=('c:\\fake_src\\buildtools\\win\\gn.exe gen //out/Debug '
                     '--check\n'))
     self.assertMultiLineEqual(mbw.files['c:\\fake_src\\out\\Debug\\args.gn'],
                               ('goma_dir = "c:\\\\goma"\n'
                                'is_debug = true\n'
                                'use_goma = true\n'))
 
+    mbw = self.fake_mbw()
+    self.check(['gen', '-m', 'fake_master', '-b', 'fake_gn_args_bot',
+                '//out/Debug'],
+               mbw=mbw, ret=0)
+    self.assertEqual(
+        mbw.files['/fake_src/out/Debug/args.gn'],
+        'import("//build/args/bots/fake_master/fake_gn_args_bot.gn")\n')
+
 
   def test_gn_gen_fails(self):
     mbw = self.fake_mbw()
     mbw.Call = lambda cmd, env=None, buffer_output=True: (1, '', '')
     self.check(['gen', '-c', 'gn_debug_goma', '//out/Default'], mbw=mbw, ret=1)
 
   def test_gn_gen_swarming(self):
     files = {
       '/tmp/swarming_targets': 'base_unittests\n',
       '/fake_src/testing/buildbot/gn_isolate_map.pyl': (
@@ skipping 109 matching lines @@
     try:
       sys.stdout = StringIO.StringIO()
       self.assertRaises(SystemExit, self.check, ['-h'])
       self.assertRaises(SystemExit, self.check, ['help'])
       self.assertRaises(SystemExit, self.check, ['help', 'gen'])
     finally:
       sys.stdout = orig_stdout
 
   def test_validate(self):
     mbw = self.fake_mbw()
-    mbw.files[mbw.default_config] = TEST_CONFIG
     self.check(['validate'], mbw=mbw, ret=0)
 
   def test_bad_validate(self):
     mbw = self.fake_mbw()
     mbw.files[mbw.default_config] = TEST_BAD_CONFIG
     self.check(['validate'], mbw=mbw, ret=1)
 
 
 if __name__ == '__main__':
   unittest.main()