diff --git a/testing/tests/l10n/lib/Mozilla/Tests.py b/testing/tests/l10n/lib/Mozilla/Tests.py
index d881e25d23681..435a1c845f6a2 100755
--- a/testing/tests/l10n/lib/Mozilla/Tests.py
+++ b/testing/tests/l10n/lib/Mozilla/Tests.py
@@ -59,13 +59,13 @@ def failureTest(self, myResult, failureResult):
 import CompareLocales
 class CompareTest(Base):
   '''Test class to compare locales'''
-  def __init__(self):
+  def __init__(self, apps = ['browser', 'mail']):
     '''Initializes the test object'''
-    # nothing to be done here
+    self.apps = apps
     pass
   def run(self):
     '''Runs CompareLocales.compare()'''
-    return CompareLocales.compare(apps=['browser','mail'])
+    return CompareLocales.compare(apps=self.apps)
   def serialize(self, result, saveHandler):
     '''Serialize the CompareLocales result by locale into
       cmp-details-ab-CD
diff --git a/testing/tests/l10n/scripts/test-locales b/testing/tests/l10n/scripts/test-locales
index a439f95f09043..3d224c91d7839 100755
--- a/testing/tests/l10n/scripts/test-locales
+++ b/testing/tests/l10n/scripts/test-locales
@@ -142,6 +142,8 @@ cp.add_option('-w','--enable-waterfall', action="store_true",
               help='Update waterfall data')
 cp.add_option('--end-date', type='string', dest='enddate',
               help='Explicit (faked) end date')
+cp.add_option('--application', type='string',
+              help='Test only one app, by default tests browser and mail')
 opts, optlist = cp.parse_args(sys.argv[1:])
 
 #
@@ -185,8 +187,11 @@ basePath = os.path.join(opts.target, opts.date)
 if not os.path.isdir(basePath):
   os.mkdir(basePath)
 
+apps = ['browser', 'mail']
+if opts.application:
+  apps = [opts.application]
 
-tests = [Tests.CompareTest(),
+tests = [Tests.CompareTest(apps = apps),
          Tests.SearchTest(),
          Tests.RSSReaderTest(),
          Tests.BookmarksTest()]