--- a/build/compare-mozconfig/compare-mozconfigs-wrapper.py
+++ b/build/compare-mozconfig/compare-mozconfigs-wrapper.py
@@ -10,35 +10,31 @@ import mozunit
 import subprocess
 import unittest
 
 from os import path
 from buildconfig import substs
 
 log = logging.getLogger(__name__)
 
-def determine_platform():
-    platform_mapping = {'WINNT': {'x86_64': 'win64',
-                                  'i686': 'win32'},
-                        'Darwin': {'x86_64': 'macosx64'},
-                        'Linux': {'x86_64': 'linux64',
-                                  'i686': 'linux32'}}
-
-    os_type = substs['OS_TARGET']
-    cpu_type = substs['TARGET_CPU']
-    return platform_mapping.get(os_type, {}).get(cpu_type, None)
+PLATFORMS = (
+    'linux32',
+    'linux64',
+    'macosx64',
+    'win32',
+    'win64',
+)
 
 
 class TestCompareMozconfigs(unittest.TestCase):
     def test_compare_mozconfigs(self):
         """ A wrapper script that calls compare-mozconfig.py
         based on the platform that the machine is building for"""
-        platform = determine_platform()
-
-        if platform is not None:
+        for platform in PLATFORMS:
+            log.info('Comparing platform %s' % platform)
             python_exe = substs['PYTHON']
             topsrcdir = substs['top_srcdir']
 
             # construct paths and args for compare-mozconfig
             browser_dir = path.join(topsrcdir, 'browser')
             script_path = path.join(topsrcdir, 'build/compare-mozconfig/compare-mozconfigs.py')
             whitelist_path = path.join(browser_dir, 'config/mozconfigs/whitelist')
             beta_mozconfig_path = path.join(browser_dir, 'config/mozconfigs', platform, 'beta')
@@ -47,17 +43,16 @@ class TestCompareMozconfigs(unittest.Tes
 
             log.info("Comparing beta against nightly mozconfigs")
             ret_code = subprocess.call([python_exe, script_path, '--whitelist',
                                         whitelist_path, '--no-download',
                                         platform + ',' + beta_mozconfig_path +
                                         ',' + nightly_mozconfig_path])
             self.assertEqual(0, ret_code)
 
-
             log.info("Comparing release against nightly mozconfigs")
             ret_code = subprocess.call([python_exe, script_path, '--whitelist',
                                         whitelist_path, '--no-download',
                                         platform + ',' + release_mozconfig_path +
                                         ',' + nightly_mozconfig_path])
             self.assertEqual(0, ret_code)
 
 if __name__ == '__main__':