--- a/layout/inspector/tests/mochitest.ini
+++ b/layout/inspector/tests/mochitest.ini
@@ -23,17 +23,16 @@ fail-if = stylo # bug 1387913
 [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/inspector/tests/test_getRelativeRuleLine.html
+++ b/layout/inspector/tests/test_getRelativeRuleLine.html
@@ -24,19 +24,21 @@
      #test {
        color: blue;
      }
   </style>
   <script type="application/javascript">
   let utils = SpecialPowers.Cc["@mozilla.org/inspector/dom-utils;1"]
                            .getService(SpecialPowers.Ci.inIDOMUtils);
 
+  const supportsRuleColumn = SpecialPowers.DOMWindowUtils.isStyledByServo ? 14
+                                                                          : 15;
   let tests = [
     { sheetNo: 0, ruleNo: 0, lineNo: 1, columnNo: 1 },
-    { sheetNo: 1, ruleNo: 0, lineNo: 2, columnNo: 15 },
+    { sheetNo: 1, ruleNo: 0, lineNo: 2, columnNo: supportsRuleColumn },
     { sheetNo: 1, ruleNo: 1, lineNo: 8, columnNo: 5 },
     { sheetNo: 2, ruleNo: 0, lineNo: 1, columnNo: 1 },
     { sheetNo: 2, ruleNo: 1, lineNo: 0, columnNo: 1 },
     { sheetNo: 3, ruleNo: 0, lineNo: 5, columnNo: 6 },
   ];
 
   function doTest() {
     document.styleSheets[2].insertRule("body{}", 1);