--- a/devtools/server/tests/mochitest/chrome.ini
+++ b/devtools/server/tests/mochitest/chrome.ini
@@ -29,16 +29,17 @@ support-files =
   webconsole-helpers.js
   webextension-helpers.js
 [test_animation_actor-lifetime.html]
 [test_connection-manager.html]
 [test_connectToChild.html]
 [test_css-logic.html]
 [test_css-logic-media-queries.html]
 [test_css-logic-specificity.html]
+fail-if = stylo # bug 1387905
 [test_css-properties.html]
 [test_Debugger.Source.prototype.introductionScript.html]
 [test_Debugger.Source.prototype.introductionType.html]
 [test_Debugger.Source.prototype.element.html]
 [test_Debugger.Script.prototype.global.html]
 [test_device.html]
 [test_executeInGlobal-outerized_this.html]
 [test_framerate_01.html]

--- a/dom/base/test/mochitest.ini
+++ b/dom/base/test/mochitest.ini
@@ -308,16 +308,17 @@ skip-if = toolkit == 'android'
 skip-if = toolkit == 'android'
 [test_bug333198.html]
 [test_bug333673.html]
 [test_bug337631.html]
 [test_bug338541.xhtml]
 [test_bug338583.html]
 skip-if = toolkit == 'android'
 [test_bug338679.html]
+fail-if = stylo # bug 1370779
 [test_bug339494.html]
 [test_bug339494.xhtml]
 [test_bug340571.html]
 [test_bug343596.html]
 [test_bug345339.html]
 [test_bug346485.html]
 [test_bug352728.html]
 [test_bug352728.xhtml]
@@ -675,16 +676,17 @@ skip-if = (toolkit == 'android') # Andro
 [test_iframe_referrer.html]
 [test_iframe_referrer_changing.html]
 [test_iframe_referrer_invalid.html]
 [test_Image_constructor.html]
 [test_img_referrer.html]
 [test_innersize_scrollport.html]
 [test_integer_attr_with_leading_zero.html]
 [test_intersectionobservers.html]
+skip-if = stylo # timeout bug 1384001
 [test_link_prefetch.html]
 skip-if = !e10s # Track Bug 1281415
 [test_link_stylesheet.html]
 [test_messagemanager_targetchain.html]
 [test_meta_viewport0.html]
 skip-if = (os != 'android')    # meta-viewport tag support is mobile-only
 [test_meta_viewport1.html]
 skip-if = (os != 'android')    # meta-viewport tag support is mobile-only
@@ -698,16 +700,17 @@ skip-if = (os != 'android')    # meta-vi
 skip-if = (os != 'android')    # meta-viewport tag support is mobile-only
 [test_meta_viewport6.html]
 skip-if = (os != 'android')    # meta-viewport tag support is mobile-only
 [test_meta_viewport7.html]
 skip-if = (os != 'android')    # meta-viewport tag support is mobile-only
 [test_mozbrowser_apis_blocked.html]
 [test_mozMatchesSelector.html]
 [test_mutationobserver_anonymous.html]
+skip-if = stylo # bug 1383985
 [test_mutationobservers.html]
 [test_named_frames.html]
 [test_navigator_hardwareConcurrency.html]
 [test_navigator_language.html]
 [test_navigatorPrefOverride.html]
 [test_noAudioNotification.html]
 tags = audiochannel
 [test_noAudioNotificationOnMutedElement.html]

--- a/dom/html/test/test_fullscreen-api.html
+++ b/dom/html/test/test_fullscreen-api.html
@@ -72,16 +72,25 @@ function shouldSkipTest(test) {
       navigator.platform.indexOf('Linux') >= 0) {
     for (let item of gLinuxE10sSkipList) {
       if (item.test == test) {
         todo(false, `${test} skipped due to ${item.reason}`);
         return true;
       }
     }
   }
+  if (SpecialPowers.DOMWindowUtils.isStyledByServo &&
+      SpecialPowers.isDebugBuild &&
+      navigator.platform.indexOf('Mac') >= 0) {
+    if (test == "file_fullscreen-backdrop.html") {
+      todo(false, `${test} skipped due to bug 1387942`);
+      return true;
+    }
+  }
+
   return false;
 }
 
 function waitForEvent(eventTarget, eventName, checkFn, callback) {
   eventTarget.addEventListener(eventName, function listener(event) {
     if (checkFn && !checkFn(event)) {
       return;
     }

--- a/image/test/mochitest/test_xultree_animation.xhtml
+++ b/image/test/mochitest/test_xultree_animation.xhtml
@@ -45,16 +45,21 @@ Mozilla Bug 666446: lots of animated gif
     </xul:window>
   </div>
 <div id="debug" style="display:none"></div>
 <pre id="test">
 <script type="text/javascript">
 
 /** Test for Bug 666446 nsSVGFEImageElement/RasterImage**/
 
+if (SpecialPowers.DOMWindowUtils.isStyledByServo) {
+  // Stylo currently asserts for any XUL bits.
+  SimpleTest.expectAssertions(9, 9);
+}
+
 const FAILURE_TIMEOUT = 5000; // Fail early after 120 seconds (2 minutes)
 
 function main() {
   var animTest = new AnimationTest(20, FAILURE_TIMEOUT, 'referenceItem',
                                    'imageItem', 'debug', '',
                                    'animated-gif-finalframe.gif', true);
   animTest.beginTest();
 }

--- a/layout/base/tests/mochitest.ini
+++ b/layout/base/tests/mochitest.ini
@@ -72,16 +72,17 @@ skip-if = toolkit == 'android' # Require
 [test_bug646757.html]
 [test_bug667512.html]
 [test_bug677878.html]
 [test_bug687297.html]
 support-files =
   bug687297_a.html
   bug687297_b.html
   bug687297_c.html
+fail-if = stylo # bug 1375332
 [test_bug696020.html]
 [test_bug718809.html]
 [test_bug725426.html]
 [test_bug731777.html]
 [test_bug749186.html]
 [test_bug761572.html]
 [test_bug770106.html]
 [test_bug842853.html]
@@ -130,16 +131,17 @@ support-files = bug1153130_inner.html
 support-files =
   bug1162990_inner_1.html
   bug1162990_inner_2.html
 [test_bug1226904.html]
 support-files = bug1226904.html
 [test_bug1246622.html]
 [test_bug1278021.html]
 [test_emulateMedium.html]
+fail-if = stylo # bug 1371395
 [test_event_target_iframe_oop.html]
 skip-if = e10s # bug 1020135, nested oop iframes not supported
 support-files = bug921928_event_target_iframe_apps_oop.html
 [test_event_target_radius.html]
 skip-if = toolkit == 'android' # Bug 1355836
 [test_flush_on_paint.html]
 skip-if = true # Bug 688128
 [test_frame_reconstruction_for_pseudo_elements.html]

--- a/layout/inspector/tests/mochitest.ini
+++ b/layout/inspector/tests/mochitest.ini
@@ -4,16 +4,17 @@ support-files =
   bug1202095-2.css
   bug856317.css
   file_bug522601.html
 
 [test_bug462787.html]
 [test_bug462789.html]
 [test_bug522601.xhtml]
 [test_bug536379.html]
+fail-if = stylo # bug 1387913
 [test_bug536379-2.html]
 [test_bug557726.html]
 [test_bug609549.xhtml]
 [test_bug806192.html]
 [test_bug856317.html]
 [test_bug877690.html]
 [test_bug1006595.html]
 [test_color_to_rgba.html]
@@ -22,14 +23,17 @@ support-files =
 [test_getCSSStyleRules.html]
 support-files =
   file_getCSSStyleRules-default.html
   file_getCSSStyleRules-alternate.html
   getCSSStyleRules-1.css
   getCSSStyleRules-2.css
 [test_getCSSPseudoElementNames.html]
 [test_getRelativeRuleLine.html]
+fail-if = stylo # bug 1387932
 [test_get_all_style_sheets.html]
 [test_is_valid_css_color.html]
 [test_isinheritableproperty.html]
 [test_parseStyleSheet.html]
 [test_parseStyleSheetImport.html]
+fail-if = stylo # bug 1387933
 [test_selectormatcheselement.html]
+fail-if = stylo # bug 1387934

--- a/layout/style/test/browser.ini
+++ b/layout/style/test/browser.ini
@@ -6,9 +6,10 @@ support-files =
   mapped.css
   mapped.css^headers^
   mapped2.css
   mapped2.css^headers^
   sourcemap_css.html
 
 [browser_bug453896.js]
 [browser_newtab_share_rule_processors.js]
+skip-if = stylo # Gecko-specific test
 [browser_sourcemap.js]

--- a/layout/style/test/mochitest.ini
+++ b/layout/style/test/mochitest.ini
@@ -234,16 +234,17 @@ skip-if = !stylo
 [test_keyframes_rules.html]
 [test_keyframes_vendor_prefix.html]
 [test_load_events_on_stylesheets.html]
 [test_logical_properties.html]
 [test_media_queries.html]
 skip-if = android_version == '18' #debug-only failure; timed out #Android 4.3 aws only; bug 1030419
 [test_media_queries_dynamic.html]
 [test_media_queries_dynamic_xbl.html]
+fail-if = stylo # bug 1382078
 [test_media_query_list.html]
 [test_moz_device_pixel_ratio.html]
 [test_namespace_rule.html]
 [test_of_type_selectors.xhtml]
 [test_page_parser.html]
 [test_parse_eof.html]
 [test_parse_ident.html]
 [test_parse_rule.html]
@@ -260,23 +261,25 @@ skip-if = android_version == '18' #debug
 [test_pseudoelement_parsing.html]
 [test_redundant_font_download.html]
 support-files = redundant_font_download.sjs
 [test_reframe_pseudo_element.html]
 [test_rem_unit.html]
 [test_restyle_table_wrapper.html]
 [test_restyles_in_smil_animation.html]
 skip-if = toolkit == 'android' # bug 1328522
+fail-if = stylo # bug 1387935
 [test_root_node_display.html]
 [test_rule_insertion.html]
 [test_rule_serialization.html]
 [test_rules_out_of_sheets.html]
 [test_selectors.html]
 skip-if = toolkit == 'android' #bug 775227
 [test_selectors_on_anonymous_content.html]
+fail-if = stylo # bug 1382102
 [test_setPropertyWithNull.html]
 [test_shorthand_property_getters.html]
 [test_specified_value_serialization.html]
 [test_style_attr_listener.html]
 [test_style_attribute_quirks.html]
 [test_style_attribute_standards.html]
 [test_style_struct_copy_constructors.html]
 [test_stylesheet_additions.html]

--- a/layout/xul/test/test_bug381167.xhtml
+++ b/layout/xul/test/test_bug381167.xhtml
@@ -21,16 +21,21 @@ https://bugzilla.mozilla.org/show_bug.cg
 </xul:tree>
 <pre id="test">
 <script type="application/javascript">
 
 /** Test for Bug 381167 **/
 
 SimpleTest.waitForExplicitFinish();
 
+if (SpecialPowers.DOMWindowUtils.isStyledByServo) {
+  // Stylo currently asserts for any XUL bits.
+  SimpleTest.expectAssertions(5, 5);
+}
+
 function closeit() {
   var evt = document.createEvent('KeyboardEvent');
                                  evt.initKeyEvent('keypress', true, true,
                                  window,
                                  true, false, false, false,
                                  'W'.charCodeAt(0), 0);
   window.dispatchEvent(evt);