Add the missing file for the test in bug 809654

content/media/webaudio/test/webaudio.js

@@ -0,0 +1,14 @@
+// Helpers for Web Audio tests
+
+function expectException(func, exceptionCode) {
+  var threw = false;
+  try {
+    func();
+  } catch (ex) {
+    threw = true;
+    ok(ex instanceof DOMException, "Expect a DOM exception");
+    ok(ex.code, exceptionCode, "Expect the correct exception code");
+  }
+  ok(threw, "The exception was thrown");
+}
+