Add Mac output for policy template generator

tools/grit/grit/format/policy_templates/writers/writer_unittest_common.py

Index: tools/grit/grit/format/policy_templates/writers/writer_unittest_common.py
diff --git a/tools/grit/grit/format/policy_templates/writers/writer_unittest_common.py b/tools/grit/grit/format/policy_templates/writers/writer_unittest_common.py
new file mode 100644
index 0000000000000000000000000000000000000000..ff7d8f5a2c8dcdfaa0eb5d16f8d6adf91866f27a
--- /dev/null
+++ b/tools/grit/grit/format/policy_templates/writers/writer_unittest_common.py
@@ -0,0 +1,74 @@
+# Copyright (c) 2010 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.
+
+'''Common tools for unit-testing writers.'''
+
+
+import os
+import sys
+if __name__ == '__main__':
+  sys.path.append(os.path.join(os.path.dirname(sys.argv[0]), '../../../..'))
+
+import tempfile
+import unittest
+import StringIO
+
+from grit import grd_reader
+from grit import util
+from grit.tool import build
+
+
+class DummyOutput(object):
+  def __init__(self, type, language, file = 'hello.gif'):
+    self.type = type
+    self.language = language
+    self.file = file
+  def GetType(self):
+    return self.type
+  def GetLanguage(self):
+    return self.language
+  def GetOutputFilename(self):
+    return self.file
+
+
+class WriterUnittestCommon(unittest.TestCase):
+  '''Common class for unittesting writers.'''
+
+  def prepareTest(self, policy_json, grd_text):
+    '''Parses a grit tree along with a data structure of policies.
+
+    Args:
+      policy_json: The policy data structure in JSON format.
+      grd_text: The grit tree in text form.
+    '''
+    tmp_file_name = 'test.json'
+    tmp_dir_name = tempfile.gettempdir()
+    json_file_path = tmp_dir_name + '/' + tmp_file_name
+    f = open(json_file_path, 'w')
+    f.write(policy_json.strip())
+    f.close()
+    grd = grd_reader.Parse(
+        StringIO.StringIO(grd_text % json_file_path), dir=tmp_dir_name)
+    grd.RunGatherers(recursive=True)
+    os.unlink(json_file_path)
+    return grd
+
+  def CompareResult(self, grd, env_lang, env_defs, out_type, out_lang,
+                    expected_output):
+    '''Generates an output of the writer and compares it with the expected
+    result. Fails if they differ.
+
+    Args:
+      grd: The root of the grit tree.
+      env_lang: The environment language.
+      env_defs: Environment definitions.
+      out_type: Type of the output node for which output will be generated.
+      out_lang: Language of the output node for which output will be generated.
+      expected_output: The expected output of the writer.
+    '''
+    grd.SetOutputContext(env_lang, env_defs)
+    buf = StringIO.StringIO()
+    build.RcBuilder.ProcessNode(grd, DummyOutput(out_type, out_lang), buf)
+    output = buf.getvalue()
+    self.assertEquals(output.strip(), expected_output.strip())