diff --git a/devtools/client/inspector/markup/test/browser.ini b/devtools/client/inspector/markup/test/browser.ini
index 361052fb0960..dc4aa3d18003 100644
--- a/devtools/client/inspector/markup/test/browser.ini
+++ b/devtools/client/inspector/markup/test/browser.ini
@@ -81,7 +81,6 @@ skip-if = os == "mac" # Full keyboard navigation on OSX only works if Full Keybo
 [browser_markup_anonymous_02.js]
 skip-if = e10s # scratchpad.xul is not loading in e10s window
 [browser_markup_anonymous_03.js]
-skip-if = stylo # Stylo doesn't support shadow DOM yet, bug 1293844
 [browser_markup_anonymous_04.js]
 [browser_markup_copy_image_data.js]
 subsuite = clipboard
diff --git a/devtools/server/tests/mochitest/test_inspector-anonymous.html b/devtools/server/tests/mochitest/test_inspector-anonymous.html
index 2085f49c4db8..06f32319dd54 100644
--- a/devtools/server/tests/mochitest/test_inspector-anonymous.html
+++ b/devtools/server/tests/mochitest/test_inspector-anonymous.html
@@ -22,8 +22,6 @@ window.onload = function () {
     require("devtools/shared/dom-node-filter-constants");
   const XUL_NS = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
 
-  const isStylo = SpecialPowers.getBoolPref("layout.css.servo.enabled");
-
   SpecialPowers.pushPrefEnv({"set": [
     ["dom.webcomponents.enabled", true]
   ]});
@@ -146,12 +144,6 @@ window.onload = function () {
   });
 
   addAsyncTest(function* testShadowAnonymous() {
-    // Stylo doesn't currently support shadow DOM (bug 1293844)
-    if (isStylo) {
-      runNextTest();
-      return;
-    }
-
     info("Testing shadow DOM content.");
 
     let shadow = yield gWalker.querySelector(gWalker.rootNode, "#shadow");
diff --git a/layout/style/test/test_keyframes_vendor_prefix.html b/layout/style/test/test_keyframes_vendor_prefix.html
index a821180bd966..f838dae1cff2 100644
--- a/layout/style/test/test_keyframes_vendor_prefix.html
+++ b/layout/style/test/test_keyframes_vendor_prefix.html
@@ -62,7 +62,13 @@ function addDiv(t, attrs) {
   return div;
 }
 
-var isStylo = SpecialPowers.getBoolPref('layout.css.servo.enabled');
+var isStylo = false;
+// 'layout.css.servo.enabled' is not yet defined on gecko, so we need a try
+// block.
+try {
+  isStylo = SpecialPowers.getBoolPref('layout.css.servo.enabled');
+} catch(e) {
+}
 
 test(function(t) {
   addStyle(t,