Get rid of TestException copy-paste
diff --git a/js/kotlinx-coroutines-core-js/test/PromiseTest.kt b/js/kotlinx-coroutines-core-js/test/PromiseTest.kt
index a431101..d0f6b2b 100644
--- a/js/kotlinx-coroutines-core-js/test/PromiseTest.kt
+++ b/js/kotlinx-coroutines-core-js/test/PromiseTest.kt
@@ -71,9 +71,7 @@
         val deferred = async { "OK" }
         val promise = deferred.asPromise()
         val d2 = promise.asDeferred()
-        assertTrue(d2 === deferred)
+        assertSame(d2, deferred)
         assertEquals("OK", d2.await())
     }
-
-    private class TestException(message: String) : Exception(message)
 }
\ No newline at end of file