new file mode 100644
--- /dev/null
+++ b/testing/mochitest/mach_test_package_commands.py
@@ -0,0 +1,41 @@
+# 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
+
+from argparse import Namespace
+import os
+
+from mach.decorators import (
+    CommandProvider,
+    Command,
+)
+
+
+def run_mochitest(context, **kwargs):
+    args = Namespace(**kwargs)
+    args.certPath = context.certs_dir
+    args.utilityPath = context.bin_dir
+    args.extraProfileFiles.append(os.path.join(context.bin_dir, 'plugins'))
+
+    from runtests import run_test_harness
+    return run_test_harness(args)
+
+
+def setup_argument_parser():
+    from mochitest_options import MochitestArgumentParser
+    return MochitestArgumentParser(app='generic')
+
+
+@CommandProvider
+class MochitestCommands(object):
+
+    def __init__(self, context):
+        self.context = context
+
+    @Command('mochitest', category='testing',
+             description='Run the mochitest harness.',
+             parser=setup_argument_parser)
+    def mochitest(self, **kwargs):
+        return run_mochitest(self.context, **kwargs)

--- a/testing/mochitest/mochitest_options.py
+++ b/testing/mochitest/mochitest_options.py
@@ -72,17 +72,17 @@ class MochitestArguments(ArgumentContain
           "help": "Always keep the browser open after tests complete.",
           }],
         [["--appname"],
          {"dest": "app",
           "default": None,
           "help": "Override the default binary used to run tests with the path provided, e.g "
                   "/usr/bin/firefox. If you have run ./mach package beforehand, you can "
                   "specify 'dist' to run tests against the distribution bundle's binary.",
-          "suppress": True,
+          "suppress": build_obj is not None,
           }],
         [["--utility-path"],
          {"dest": "utilityPath",
           "default": build_obj.bindir if build_obj is not None else None,
           "help": "absolute path to directory containing utility programs "
                   "(xpcshell, ssltunnel, certutil)",
           "suppress": True,
           }],
@@ -580,17 +580,19 @@ class MochitestArguments(ArgumentContain
             elif build_obj is not None:
                 # otherwise default to dist/bin
                 options.xrePath = build_obj.bindir
             else:
                 parser.error(
                     "could not find xre directory, --xre-path must be specified")
 
         # allow relative paths
-        options.xrePath = self.get_full_path(options.xrePath, parser.oldcwd)
+        if options.xrePath:
+            options.xrePath = self.get_full_path(options.xrePath, parser.oldcwd)
+
         if options.profilePath:
             options.profilePath = self.get_full_path(options.profilePath, parser.oldcwd)
 
         if options.dmdPath:
             options.dmdPath = self.get_full_path(options.dmdPath, parser.oldcwd)
 
         if options.dmd and not options.dmdPath:
             if build_obj:
@@ -1145,17 +1147,17 @@ container_map = {
     'generic': [MochitestArguments],
     'b2g': [MochitestArguments, B2GArguments],
     'android': [MochitestArguments, AndroidArguments],
 }
 
 
 class MochitestArgumentParser(ArgumentParser):
     """
-    Usage instructions for runtests.py.
+    Usage instructions for Mochitest.
 
     All arguments are optional.
     If --chrome is specified, chrome tests will be run instead of web content tests.
     If --browser-chrome is specified, browser-chrome tests will be run instead of web content tests.
     See <http://mochikit.com/doc/html/MochiKit/Logging.html> for details on the logging levels.
     """
 
     _containers = None

--- a/testing/mochitest/moz.build
+++ b/testing/mochitest/moz.build
@@ -53,16 +53,17 @@ TEST_HARNESS_FILES.testing.mochitest += 
     'chrome-harness.js',
     'chunkifyTests.js',
     'gen_template.pl',
     'harness.xul',
     'jetpack-addon-harness.js',
     'jetpack-addon-overlay.xul',
     'jetpack-package-harness.js',
     'jetpack-package-overlay.xul',
+    'mach_test_package_commands.py',
     'manifest.webapp',
     'manifestLibrary.js',
     'mochitest_options.py',
     'nested_setup.js',
     'pywebsocket_wrapper.py',
     'redirect.html',
     'runtests.py',
     'runtestsb2g.py',

--- a/testing/tools/mach_test_package_bootstrap.py
+++ b/testing/tools/mach_test_package_bootstrap.py
@@ -6,21 +6,38 @@ from __future__ import print_function, u
 
 import os
 import platform
 import sys
 import time
 
 
 SEARCH_PATHS = [
+    'mochitest',
+    'mozbase/mozcrash',
+    'mozbase/mozdebug',
+    'mozbase/mozdevice',
+    'mozbase/mozfile',
+    'mozbase/mozhttpd',
+    'mozbase/mozlog',
+    'mozbase/moznetwork',
+    'mozbase/mozprocess',
+    'mozbase/mozprofile',
+    'mozbase/mozrunner',
+    'mozbase/mozsystemmonitor',
+    'mozbase/mozinfo',
+    'mozbase/moztest',
+    'mozbase/mozversion',
+    'mozbase/manifestparser',
     'tools/mach',
 ]
 
 # Individual files providing mach commands.
 MACH_MODULES = [
+    'mochitest/mach_test_package_commands.py',
     'tools/mach/mach/commands/commandinfo.py',
 ]
 
 
 CATEGORIES = {
     'testing': {
         'short': 'Testing',
         'long': 'Run tests.',
@@ -55,16 +72,20 @@ def bootstrap(test_package_root):
 
     try:
         import mach.main
     except ImportError:
         sys.path[0:0] = [os.path.join(test_package_root, path) for path in SEARCH_PATHS]
         import mach.main
 
     def populate_context(context, key=None):
+        context.package_root = test_package_root
+        context.certs_dir = os.path.join(test_package_root, 'certs')
+        context.bin_dir = os.path.join(test_package_root, 'bin')
+        context.modules_dir = os.path.join(test_package_root, 'modules')
         return context
 
     mach = mach.main.Mach(os.getcwd())
     mach.populate_context_handler = populate_context
 
     for category, meta in CATEGORIES.items():
         mach.define_category(category, meta['short'], meta['long'],
             meta['priority'])