--- a/toolkit/components/telemetry/tests/unit/test_ThreadHangStats.js
+++ b/toolkit/components/telemetry/tests/unit/test_ThreadHangStats.js
@@ -82,19 +82,21 @@ function run_test() {
 
       ok(Array.isArray(endHangs.hangs[0].stack));
       notEqual(endHangs.hangs[0].stack.length, 0);
       equal(typeof endHangs.hangs[0].stack[0], "string");
 
       // Make sure one of the hangs is a permanent
       // hang containing a native stack.
       ok(endHangs.hangs.some((hang) => (
-        Array.isArray(hang.nativeStack) &&
-        hang.nativeStack.length !== 0 &&
-        typeof hang.nativeStack[0] === "string"
+        hang.nativeStack &&
+        Array.isArray(hang.nativeStack.memoryMap) &&
+        hang.nativeStack.memoryMap.length !== 0 &&
+        Array.isArray(hang.nativeStack.stacks) &&
+        hang.nativeStack.stacks.length !== 0
       )));
 
       check_histogram(endHangs.hangs[0].histogram);
 
       do_test_finished();
     };
 
     check_results();