diff --git a/b2g/chrome/content/test/mochitest/mochitest.ini b/b2g/chrome/content/test/mochitest/mochitest.ini
index 0d60bb873d88..6fa343e9a43e 100644
--- a/b2g/chrome/content/test/mochitest/mochitest.ini
+++ b/b2g/chrome/content/test/mochitest/mochitest.ini
@@ -1,5 +1,5 @@
 [DEFAULT]
-skip-if = (buildapp == 'b2g' && toolkit != 'gonk') #require OOP support for mochitest-b2g-desktop, Bug 957554
+skip-if = ((mulet || buildapp == 'b2g') && toolkit != 'gonk') #require OOP support for mochitest-b2g-desktop, Bug 957554
 support-files =
   RecordingStatusChromeScript.js
   RecordingStatusHelper.js
diff --git a/browser/base/content/test/general/browser.ini b/browser/base/content/test/general/browser.ini
index cde3ea08095d..8c09abf8ce65 100644
--- a/browser/base/content/test/general/browser.ini
+++ b/browser/base/content/test/general/browser.ini
@@ -280,7 +280,7 @@ skip-if = e10s # Bug ????? - thumbnail captures need e10s love (tabPreviews_capt
 [browser_datareporting_notification.js]
 run-if = datareporting
 [browser_devices_get_user_media.js]
-skip-if = (os == "linux" && debug) || e10s # linux: bug 976544; e10s: Bug ?????? - appears user media notifications only happen in the child and don't make their way to the parent?
+skip-if = mulet || (os == "linux" && debug) || e10s # linux: bug 976544; e10s: Bug ?????? - appears user media notifications only happen in the child and don't make their way to the parent?
 [browser_discovery.js]
 skip-if = e10s # Bug 918663 - DOMLinkAdded events don't make their way to chrome
 [browser_duplicateIDs.js]
@@ -320,7 +320,7 @@ skip-if = e10s # Bug ?????? - test directly manipulates content ("cannot ipc non
 [browser_notification_tab_switching.js]
 skip-if = e10s # Bug ?????? - uncaught exception - Error: cannot ipc non-cpow object at chrome://mochitests/content/browser/browser/base/content/test/general/browser_notification_tab_switching.js:32
 [browser_offlineQuotaNotification.js]
-skip-if = e10s # Bug ?????? - test directly manipulates content (gBrowser.selectedBrowser.contentWindow.applicationCache.oncached = function() {...})
+skip-if = mulet || e10s # Bug ?????? - test directly manipulates content (gBrowser.selectedBrowser.contentWindow.applicationCache.oncached = function() {...})
 [browser_overflowScroll.js]
 skip-if = e10s # Bug 921905 - pinTab/unpinTab fail in e10s
 [browser_pageInfo.js]
diff --git a/content/canvas/test/mochitest.ini b/content/canvas/test/mochitest.ini
index aee5f270ee84..c48e87f6c7b1 100644
--- a/content/canvas/test/mochitest.ini
+++ b/content/canvas/test/mochitest.ini
@@ -201,7 +201,7 @@ skip-if = os == "android" || appname == "b2g"
 [test_drawImage_edge_cases.html]
 [test_drawWindow.html]
 support-files = file_drawWindow_source.html file_drawWindow_common.js
-skip-if = (buildapp == 'b2g' && toolkit != 'gonk')
+skip-if = mulet || (buildapp == 'b2g' && toolkit != 'gonk')
 [test_ImageData_ctor.html]
 [test_isPointInStroke.html]
 [test_mozDashOffset.html]
diff --git a/content/canvas/test/webgl-mochitest/mochitest.ini b/content/canvas/test/webgl-mochitest/mochitest.ini
index feebe5f0185a..2b1a889a502b 100644
--- a/content/canvas/test/webgl-mochitest/mochitest.ini
+++ b/content/canvas/test/webgl-mochitest/mochitest.ini
@@ -14,7 +14,7 @@ support-files =
 [test_webgl_available.html]
 skip-if = toolkit == 'android' #bug 865443- seperate suite - the non_conf* tests pass except for one on armv6 tests
 [test_webgl_conformance.html]
-skip-if = toolkit == 'android' #bug 865443- seperate suite - the non_conf* tests pass except for one on armv6 tests
+skip-if = mulet || toolkit == 'android' #bug 865443- seperate suite - the non_conf* tests pass except for one on armv6 tests
 [test_webgl_request_context.html]
 skip-if = toolkit == 'android' #bug 865443- seperate suite - the non_conf* tests pass except for one on armv6 tests
 [test_webgl_request_mismatch.html]
diff --git a/content/html/content/test/mochitest.ini b/content/html/content/test/mochitest.ini
index c0f589642fde..5686f94776c3 100644
--- a/content/html/content/test/mochitest.ini
+++ b/content/html/content/test/mochitest.ini
@@ -422,7 +422,7 @@ skip-if = buildapp == 'b2g' || toolkit == 'android' || e10s #TIMED_OUT # b2g(NS_
 skip-if = toolkit == 'android'
 [test_formelements.html]
 [test_fullscreen-api.html]
-skip-if = buildapp == 'b2g' || toolkit == 'android' || e10s #TIMED_OUT # b2g(time out, some kind of focus issue) b2g-debug(time out, some kind of focus issue) b2g-desktop(time out, some kind of focus issue)
+skip-if = mulet || buildapp == 'b2g' || toolkit == 'android' || e10s #TIMED_OUT # b2g(time out, some kind of focus issue) b2g-debug(time out, some kind of focus issue) b2g-desktop(time out, some kind of focus issue)
 [test_hidden.html]
 [test_html_attributes_reflection.html]
 [test_htmlcollection.html]
diff --git a/dom/alarm/test/mochitest.ini b/dom/alarm/test/mochitest.ini
index 5a1f6edb9961..e923ffaf3e28 100644
--- a/dom/alarm/test/mochitest.ini
+++ b/dom/alarm/test/mochitest.ini
@@ -2,12 +2,12 @@
 skip-if = e10s
 
 [test_alarm_add_data.html]
-skip-if = (buildapp == 'b2g' && toolkit != 'gonk') #Bug 931116, b2g desktop specific, initial triage
+skip-if = ((mulet || buildapp == 'b2g') && toolkit != 'gonk') #Bug 931116, b2g desktop specific, initial triage
 [test_alarm_add_date.html]
-skip-if = (buildapp == 'b2g' && toolkit != 'gonk') #Bug 931116, b2g desktop specific, initial triage
+skip-if = ((mulet || buildapp == 'b2g') && toolkit != 'gonk') #Bug 931116, b2g desktop specific, initial triage
 [test_alarm_add_respectTimezone.html]
-skip-if = (buildapp == 'b2g' && toolkit != 'gonk') #Bug 931116, b2g desktop specific, initial triage
+skip-if = ((mulet || buildapp == 'b2g') && toolkit != 'gonk') #Bug 931116, b2g desktop specific, initial triage
 [test_alarm_non_permitted_app.html]
 [test_alarm_permitted_app.html]
 [test_alarm_remove.html]
-skip-if = (buildapp == 'b2g' && toolkit != 'gonk') #Bug 931116, b2g desktop specific, initial triage
+skip-if = ((mulet || buildapp == 'b2g') && toolkit != 'gonk') #Bug 931116, b2g desktop specific, initial triage
diff --git a/dom/downloads/tests/mochitest.ini b/dom/downloads/tests/mochitest.ini
index 4b200d829c88..344e1472e128 100644
--- a/dom/downloads/tests/mochitest.ini
+++ b/dom/downloads/tests/mochitest.ini
@@ -1,5 +1,5 @@
 [DEFAULT]
-skip-if = buildapp == 'b2g' # bug 979446, frequent failures
+skip-if = mulet || buildapp == 'b2g' # bug 979446, frequent failures
 support-files =
   serve_file.sjs
 
diff --git a/dom/messages/test/mochitest.ini b/dom/messages/test/mochitest.ini
index 7ebc13d88c34..ad1cdad14bb6 100644
--- a/dom/messages/test/mochitest.ini
+++ b/dom/messages/test/mochitest.ini
@@ -2,4 +2,4 @@
 skip-if = e10s
 
 [test_bug_993732.html]
-skip-if = (buildapp == 'b2g' && toolkit != 'gonk') #Bug 931116, b2g desktop specific, initial triage
+skip-if = mulet || (buildapp == 'b2g' && toolkit != 'gonk') #Bug 931116, b2g desktop specific, initial triage
diff --git a/dom/permission/tests/mochitest.ini b/dom/permission/tests/mochitest.ini
index 2b096ac8050f..f6e48ff5830b 100644
--- a/dom/permission/tests/mochitest.ini
+++ b/dom/permission/tests/mochitest.ini
@@ -7,7 +7,7 @@ support-files =
 [test_alarms.html]
 [test_browser.html]
 [test_embed-apps.html]
-skip-if = (buildapp == 'b2g' && toolkit != 'gonk') #Bug 931116, b2g desktop specific, initial triage
+skip-if = ((mulet || buildapp == 'b2g') && toolkit != 'gonk') #Bug 931116, b2g desktop specific, initial triage
 [test_idle.html]
 skip-if = (toolkit == 'gonk' && debug) #debug-only failure
 [test_permission_basics.html]
diff --git a/dom/settings/tests/chrome.ini b/dom/settings/tests/chrome.ini
index 3c844ae49cc7..584cd112143f 100644
--- a/dom/settings/tests/chrome.ini
+++ b/dom/settings/tests/chrome.ini
@@ -2,3 +2,4 @@
 
 [test_settings_service.js]
 [test_settings_service.xul]
+skip-if= mulet
diff --git a/dom/tests/mochitest/general/mochitest.ini b/dom/tests/mochitest/general/mochitest.ini
index 7f17199ba64c..1a2441c523dd 100644
--- a/dom/tests/mochitest/general/mochitest.ini
+++ b/dom/tests/mochitest/general/mochitest.ini
@@ -42,7 +42,7 @@ skip-if = buildapp == 'b2g' || toolkit == 'android' #TIMED_OUT
 [test_idleapi_permissions.html]
 skip-if = buildapp == 'b2g'
 [test_interfaces.html]
-skip-if = (buildapp == 'b2g' && toolkit != 'gonk') #Bug 931116, b2g desktop specific, initial triage
+skip-if = ((mulet || buildapp == 'b2g') && toolkit != 'gonk') #Bug 931116, b2g desktop specific, initial triage
 # [test_network_events.html]
 # Disable this test until bug 795711 is fixed.
 [test_offsets.html]
diff --git a/python/mozbuild/mozbuild/mozinfo.py b/python/mozbuild/mozbuild/mozinfo.py
index b3e72711df72..978ef9054b23 100755
--- a/python/mozbuild/mozbuild/mozinfo.py
+++ b/python/mozbuild/mozbuild/mozinfo.py
@@ -83,6 +83,7 @@ def build_dict(config, env=os.environ):
     d['asan'] = substs.get('MOZ_ASAN') == '1'
     d['tests_enabled'] = substs.get('ENABLE_TESTS') == "1"
     d['bin_suffix'] = substs.get('BIN_SUFFIX', '')
+    d['mulet'] = bool(substs.get('MOZ_MULET'))
 
     d['webm'] = bool(substs.get('MOZ_WEBM'))
     d['wave'] = bool(substs.get('MOZ_WAVE'))
diff --git a/toolkit/webapps/tests/chrome.ini b/toolkit/webapps/tests/chrome.ini
index e5547e96103f..44984db725c5 100644
--- a/toolkit/webapps/tests/chrome.ini
+++ b/toolkit/webapps/tests/chrome.ini
@@ -1,4 +1,5 @@
 [DEFAULT]
+skip-if= mulet
 support-files =
   head.js
   app.sjs