--- a/testing/mochitest/mochitest_options.py
+++ b/testing/mochitest/mochitest_options.py
@@ -1,15 +1,16 @@
 # 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 abc import ABCMeta, abstractmethod, abstractproperty
 from argparse import ArgumentParser, SUPPRESS
 from distutils.util import strtobool
+from distutils import spawn
 from itertools import chain
 from urlparse import urlparse
 import logging
 import json
 import os
 import tempfile
 
 from mozdevice import DroidADB
@@ -799,21 +800,30 @@ class MochitestArguments(ArgumentContain
             if not os.path.isdir(options.dumpOutputDirectory):
                 parser.error('--dump-output-directory not a directory: %s' %
                              options.dumpOutputDirectory)
 
         if options.useTestMediaDevices:
             if not mozinfo.isLinux:
                 parser.error(
                     '--use-test-media-devices is only supported on Linux currently')
-            for f in ['/usr/bin/gst-launch-0.10', '/usr/bin/pactl']:
-                if not os.path.isfile(f):
-                    parser.error(
-                        'Missing binary %s required for '
-                        '--use-test-media-devices' % f)
+
+            gst01 = spawn.find_executable("gst-launch-0.1")
+            gst10 = spawn.find_executable("gst-launch-1.0")
+            pactl = spawn.find_executable("pactl")
+
+            if not (gst01 or gst10):
+                parser.error(
+                    'Missing gst-launch-{0.1,1.0}, required for '
+                    '--use-test-media-devices')
+
+            if not pactl:
+                parser.error(
+                    'Missing binary pactl required for '
+                    '--use-test-media-devices')
 
         if options.nested_oop:
             options.e10s = True
 
         options.leakThresholds = {
             "default": options.defaultLeakThreshold,
             "tab": options.defaultLeakThreshold,
             # GMP rarely gets a log, but when it does, it leaks a little.

--- a/testing/mochitest/runtests.py
+++ b/testing/mochitest/runtests.py
@@ -10,16 +10,17 @@ from __future__ import with_statement
 import os
 import sys
 SCRIPT_DIR = os.path.abspath(os.path.realpath(os.path.dirname(__file__)))
 sys.path.insert(0, SCRIPT_DIR)
 
 from argparse import Namespace
 from collections import defaultdict
 from contextlib import closing
+from distutils import spawn
 import copy
 import ctypes
 import glob
 import json
 import mozcrash
 import mozdebug
 import mozinfo
 import mozprocess
@@ -739,38 +740,47 @@ def findTestMediaDevices(log):
             device = dev
             break
 
     if not (name and device):
         log.error('Couldn\'t find a v4l2loopback video device')
         return None
 
     # Feed it a frame of output so it has something to display
-    subprocess.check_call(['/usr/bin/gst-launch-0.10', 'videotestsrc',
+    gst01 = spawn.find_executable("gst-launch-0.1")
+    gst10 = spawn.find_executable("gst-launch-1.0")
+    if gst01:
+        gst = gst01
+    else:
+        gst = gst10
+    subprocess.check_call([gst, 'videotestsrc',
                            'pattern=green', 'num-buffers=1', '!',
                            'v4l2sink', 'device=%s' % device])
     info['video'] = name
 
+    pactl = spawn.find_executable("pactl")
+    pacmd = spawn.find_executable("pacmd")
+
     # Use pactl to see if the PulseAudio module-null-sink module is loaded.
     def null_sink_loaded():
         o = subprocess.check_output(
-            ['/usr/bin/pactl', 'list', 'short', 'modules'])
+            [pactl, 'list', 'short', 'modules'])
         return filter(lambda x: 'module-null-sink' in x, o.splitlines())
 
     if not null_sink_loaded():
         # Load module-null-sink
-        subprocess.check_call(['/usr/bin/pactl', 'load-module',
+        subprocess.check_call([pactl, 'load-module',
                                'module-null-sink'])
 
     if not null_sink_loaded():
         log.error('Couldn\'t load module-null-sink')
         return None
 
     # Whether it was loaded or not make it the default output
-    subprocess.check_call(['/usr/bin/pacmd', 'set-default-sink', 'null'])
+    subprocess.check_call([pacmd, 'set-default-sink', 'null'])
 
     # Hardcode the name since it's always the same.
     info['audio'] = 'Monitor of Null Output'
     return info
 
 
 class KeyValueParseError(Exception):