Allow specificying that only target_os should be used in a gclient file

tests/gclient_test.py

 #!/usr/bin/env python
 # Copyright (c) 2012 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.
 
 """Unit tests for gclient.py.
 
 See gclient_smoketest.py for integration tests.
 """
 
@@ skipping 289 matching lines @@
         '  "baz": { "foo/dir3": "/dir3", },\n'
         '}')
 
     parser = gclient.Parser()
     options, _ = parser.parse_args(['--jobs', '1'])
     options.deps_os = "unix"
 
     obj = gclient.GClient.LoadCurrentConfig(options)
     self.assertEqual(['baz', 'unix'], sorted(obj.enforced_os))
 
+  def testTargetOsWithIgnoredHost(self):
+    """Verifies that specifying a target_os and target_os_only pulls in only
+    the relevant dependencies.
+
+    The target_os variable allows specifying the name of an additional OS which
+    should be considered when selecting dependencies from a DEPS' deps_os. With
+    target_os_only also set, the _enforced_os tuple will be set to only the
+    target_os value.
+    """
+
+    write(
+        '.gclient',
+        'solutions = [\n'
+        '  { "name": "foo",\n'
+        '    "url": "svn://example.com/foo",\n'
+        '  }]\n'
+        'target_os = ["baz"]\n'
+        'target_os_only = True')
+    write(
+        os.path.join('foo', 'DEPS'),
+        'deps = {\n'
+        '  "foo/dir1": "/dir1",'
+        '}\n'
+        'deps_os = {\n'
+        '  "unix": { "foo/dir2": "/dir2", },\n'
+        '  "baz": { "foo/dir3": "/dir3", },\n'
+        '}')
+
+    parser = gclient.Parser()
+    options, _ = parser.parse_args(['--jobs', '1'])
+    options.deps_os = "unix"
+
+    obj = gclient.GClient.LoadCurrentConfig(options)
+    self.assertEqual(['baz'], sorted(obj.enforced_os))
+
   def testTargetOsInDepsFile(self):
     """Verifies that specifying a target_os value in a DEPS file pulls in all
     relevant dependencies.
 
     The target_os variable in a DEPS file allows specifying the name of an
     additional OS which should be considered when selecting dependencies from a
     DEPS' deps_os. The value will be appended to the _enforced_os tuple.
     """
 
     write(
@@ skipping 93 matching lines @@
   sys.stdout = gclient_utils.MakeFileAutoFlush(sys.stdout)
   sys.stdout = gclient_utils.MakeFileAnnotated(sys.stdout, include_zero=True)
   sys.stderr = gclient_utils.MakeFileAutoFlush(sys.stderr)
   sys.stderr = gclient_utils.MakeFileAnnotated(sys.stderr, include_zero=True)
   logging.basicConfig(
       level=[logging.ERROR, logging.WARNING, logging.INFO, logging.DEBUG][
         min(sys.argv.count('-v'), 3)],
       format='%(relativeCreated)4d %(levelname)5s %(module)13s('
               '%(lineno)d) %(message)s')
   unittest.main()