Add tests for makefile_writer.py.

platform_tools/android/gyp_gen/makefile_writer.py

 #!/usr/bin/python
 
 # Copyright 2014 Google Inc.
 #
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """
 Functions for creating an Android.mk from already created dictionaries.
 """
 
 import os
 
-# TODO(scroggo): Add unit tests for this file.
 def write_group(f, name, items, append):
   """
   Helper function to list all names passed to a variable.
   @param f File open for writing (Android.mk)
   @param name Name of the makefile variable (e.g. LOCAL_CFLAGS)
   @param items list of strings to be passed to the variable.
   @param append Whether to append to the variable or overwrite it.
   """
   if not items:
     return
@@ skipping 169 matching lines @@
         f.write('ifeq ($(%s), true)\n' % data.condition)
       write_local_vars(f, data.vars_dict, True, data.name)
       if data.condition:
         f.write('endif\n\n')
 
     f.write('include external/stlport/libstlport.mk\n')
     f.write('LOCAL_MODULE:= libskia\n')
     f.write('include $(BUILD_SHARED_LIBRARY)\n')
     f.write(SKIA_TOOLS)