1 files changed, 3 insertions, 2 deletions
diff --git a/toolkit/components/extensions/test/browser/browser_ext_themes_sanitization.js b/toolkit/components/extensions/test/browser/browser_ext_themes_sanitization.js
index 89ebd3ae68..fdee1eb72d 100644
--- a/toolkit/components/extensions/test/browser/browser_ext_themes_sanitization.js
+++ b/toolkit/components/extensions/test/browser/browser_ext_themes_sanitization.js
@@ -114,8 +114,9 @@ add_task(async function test_sanitization_transparent() {
   await extension.startup();
 
   let navbar = document.querySelector("#nav-bar");
-  Assert.ok(
-    window.getComputedStyle(navbar).boxShadow.includes("rgba(0, 0, 0, 0)"),
+  Assert.equal(
+    window.getComputedStyle(navbar).borderTopColor,
+    "rgba(0, 0, 0, 0)",
     "Top separator should be transparent"
   );