Add the ability to specify a target_os for gclient solutions

tests/gclient_test.py

Index: tests/gclient_test.py
===================================================================
--- tests/gclient_test.py	(revision 134268)
+++ tests/gclient_test.py	(working copy)
@@ -275,7 +275,44 @@
     work_queue.flush({}, None, [], options=options)
     self.assertEqual(client.GetHooks(options), [x['action'] for x in hooks])
 
+  def testTargetOS(self):
+    """Verifies that specifying a target_os pulls in all 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. The
+    value will be appended to the _enforced_os tuple.
+    """
+
+    write(
+        '.gclient',
+        """
+solutions = [

[M-A Ruel, 2012/04/27 16:03:37]

style nit: If you look at the rest of this file, I tend to never use """foo"""
for data because it screws up readability IMHO. The irregular alignment make the
whole file much harder to quickly scan the test cases. And unreadable unit tests
are unit tests that are never improved. So in general, I prefer something like:
foo = (
  'bar\n'
  'baz\n'
  'booze\n'
)

It only requires a few vim keystroke to convert and the constant is not affected
by the file's EOL style for example.

[John Grabowski, 2012/04/27 16:06:26]

Ha!  I told pete the opposite.
I think """ is preferred in general for multi-line strings, but this is your
file...

+  { "name": "foo",
+    "url": "svn://example.com/foo",
+  }
+]
+target_os = ["baz"]""")
+    write(
+        os.path.join('foo', 'DEPS'),
+        """
+deps = {
+  "foo/dir1": "/dir1"
+}
+deps_os = {
+  "unix": { "foo/dir2": "/dir2" },
+  "baz": { "foo/dir3": "/dir3" }
+}""")
+
+    parser = gclient.Parser()
+    options, args = parser.parse_args(['--jobs', '1'])
+    options.deps_os = "unix"
+
+    obj = gclient.GClient.LoadCurrentConfig(options)
+    obj.RunOnDeps('None', args)
+
+    self.assertEqual(4, len(self._get_processed()))
+    
+
 if __name__ == '__main__':
   sys.stdout = gclient_utils.MakeFileAutoFlush(sys.stdout)
   sys.stdout = gclient_utils.MakeFileAnnotated(sys.stdout, include_zero=True)