Bug 1153413 - Add --subsuite option to mochitest mach command, r=jgriffin

--HG--
extra : rebase_source : 535b0a108de9b517d1b4b3a73275fbacb9e09492
extra : source : f3e21cdfa1fc1488247e27b572825ac63d2ff151

testing/mochitest/mach_commands.py

@@ -338,7 +338,6 @@ class MochitestRunner(MozbuildObject):
             flavor = 'browser-chrome'
         elif suite == 'devtools':
             options.browserChrome = True
-            options.subsuite = 'devtools'
         elif suite == 'jetpack-package':
             options.jetpackPackage = True
         elif suite == 'jetpack-addon':
@@ -411,6 +410,9 @@ class MochitestRunner(MozbuildObject):
         for k, v in kwargs.iteritems():
             setattr(options, k, v)
 
+        if suite == 'devtools':
+            options.subsuite = 'devtools'
+
         if test_paths:
             resolver = self._spawn(TestResolver)
 
@@ -731,6 +733,13 @@ def add_mochitest_general_args(parser):
              "multiple times in which case the test must contain at least one "
              "of the given tags.")
 
+    parser.add_argument(
+        "--subsuite",
+        default=None,
+        help="Subsuite of tests to run. Unlike tags, subsuites also remove "
+             "tests from the default set. Only one can be specified at once.")
+
+
     return parser
 
 def add_mochitest_b2g_args(parser):