Add a test for escaping of backslashes in list expansion

test/variables/commands/commands.gyp

 # Copyright (c) 2009 Google Inc. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # This is a simple test file to make sure that variable substitution
 # happens correctly.  Run "run_tests.py" using python to generate the
 # output from this gyp file.
 
 {
   'variables': {
@@ skipping 40 matching lines @@
         'var9': '<(check_str_int)',
         'var10': '<(check_list_int)',
         'var11': ['<@(check_list_int)'],
         'var12': '<(not_int_1)',
         'var13': '<(not_int_2)',
         'var14': '<(not_int_3)',
         'var15': '<(not_int_4)',
         'var16': '<(not_int_5)',
         'var17': '<(negative_int)',
         'var18': '<(zero_int)',
+        'var19': ['<!@(python test.py)'],
+        'var20': '<!(python test.py)',
       },
       'actions': [
         {
           'action_name': 'test_action',
           'variables': {
             'var7': '<!(echo <(var5)<(var6))',
           },
           'inputs' : [
             '<(var2)',
           ],
           'outputs': [
             '<(var4)',
             '<(var7)',
           ],
           'action': [
             'echo',
             '<(_inputs)',
             '<(_outputs)',
           ],
         },
       ],
     },
   ],
 }