--- a/layout/tools/reftest/mach_commands.py
+++ b/layout/tools/reftest/mach_commands.py
@@ -2,30 +2,31 @@
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 from __future__ import unicode_literals
 
 import os
 
 from mozbuild.base import MozbuildObject
-from mozbuild.testing.test import TestRunner
+
+from moztesting.util import parse_test_path
 
 from mach.base import (
     CommandArgument,
     CommandProvider,
     Command,
 )
 
 
 generic_help = 'Test to run. Can be specified as a single file, a ' +\
 'directory, or omitted. If omitted, the entire test suite is executed.'
 
 
-class ReftestRunner(TestRunner):
+class ReftestRunner(MozbuildObject):
     """Easily run reftests.
 
     This currently contains just the basics for running reftests. We may want
     to hook up result parsing, etc.
     """
 
     def _manifest_file(self, suite):
         """Returns the manifest file used for a given test suite."""
@@ -33,17 +34,17 @@ class ReftestRunner(TestRunner):
           'reftest': 'reftest.list',
           'crashtest': 'crashtests.list'
         }
         assert suite in files
         return files[suite]
 
     def _find_manifest(self, suite, test_file):
         assert test_file
-        parsed = self._parse_test_path(test_file)
+        parsed = parse_test_path(test_file, self.topsrcdir)
         if parsed['is_dir']:
             return os.path.join(parsed['normalized'], self._manifest_file(suite))
 
         if parsed['normalized'].endswith('.list'):
             return parsed['normalized']
 
         raise Exception('Running a single test is not currently supported')
 

--- a/mach
+++ b/mach
@@ -23,16 +23,17 @@ SEARCH_PATHS = [
     'python/mozbuild',
     'build',
     'build/pymake',
     'python/blessings',
     'python/psutil',
     'python/which',
     'other-licenses/ply',
     'xpcom/idl-parser',
+    'testing',
     'testing/xpcshell',
     'testing/mozbase/mozprocess',
     'testing/mozbase/mozinfo',
 ]
 
 # Individual files providing mach commands.
 MACH_MODULES = [
     'layout/tools/reftest/mach_commands.py',

deleted file mode 100644

--- a/testing/mochitest/mach_commands.py
+++ b/testing/mochitest/mach_commands.py
@@ -2,30 +2,31 @@
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 from __future__ import unicode_literals
 
 import os
 
 from mozbuild.base import MozbuildObject
-from mozbuild.testing.test import TestRunner
+
+from moztesting.util import parse_test_path
 
 from mach.base import (
     CommandArgument,
     CommandProvider,
     Command,
 )
 
 
 generic_help = 'Test to run. Can be specified as a single file, a ' +\
 'directory, or omitted. If omitted, the entire test suite is executed.'
 
 
-class MochitestRunner(TestRunner):
+class MochitestRunner(MozbuildObject):
     """Easily run mochitests.
 
     This currently contains just the basics for running mochitests. We may want
     to hook up result parsing, etc.
     """
     def run_plain_suite(self):
         """Runs all plain mochitests."""
         # TODO hook up Python harness runner.
@@ -66,17 +67,17 @@ class MochitestRunner(TestRunner):
         elif suite == 'browser':
             target = 'mochitest-browser-chrome'
         elif suite == 'a11y':
             target = 'mochitest-a11y'
         else:
             raise Exception('None or unrecognized mochitest suite type.')
 
         if test_file:
-            path = self._parse_test_path(test_file)['normalized']
+            path = parse_test_path(test_file, self.topsrcdir)['normalized']
             if not os.path.exists(path):
                 raise Exception('No manifest file was found at %s.' % path)
             env = {'TEST_PATH': path}
         else:
             env = {}
 
         self._run_make(directory='.', target=target, append_env=env)
 

new file mode 100644

rename from python/mozbuild/mozbuild/testing/test.py
rename to testing/moztesting/util.py
--- a/python/mozbuild/mozbuild/testing/test.py
+++ b/testing/moztesting/util.py
@@ -1,33 +1,29 @@
 # This Source Code Form is subject to the terms of the Mozilla Public
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 from __future__ import unicode_literals
 
 import os
 
-from mozbuild.base import MozbuildObject
-
-
-class TestRunner(MozbuildObject):
-    """Base class to share code for parsing test paths."""
 
-    def _parse_test_path(self, test_path):
-        """Returns a dict containing:
-        * 'normalized': the normalized path, relative to the topsrcdir
-        * 'isdir': whether the path points to a directory
-        """
-        is_dir = os.path.isdir(test_path)
+def parse_test_path(test_path, topsrcdir):
+    """Returns a dict containing:
+    * 'normalized': the normalized path, relative to the topsrcdir
+    * 'isdir': whether the path points to a directory
+    """
+    is_dir = os.path.isdir(test_path)
+
+    if is_dir and not test_path.endswith(os.path.sep):
+        test_path += os.path.sep
 
-        if is_dir and not test_path.endswith(os.path.sep):
-            test_path += os.path.sep
+    normalized = test_path
 
-        normalized = test_path
+    if test_path.startswith(topsrcdir):
+        normalized = test_path[len(topsrcdir):]
 
-        if test_path.startswith(self.topsrcdir):
-            normalized = test_path[len(self.topsrcdir):]
+    return {
+        'normalized': normalized,
+        'is_dir': is_dir,
+    }
 
-        return {
-            'normalized': normalized,
-            'is_dir': is_dir,
-        }