message: test: adding coverage tests
  should return undefined when not open
diff: @@ -26,6 +26,14 @@ describe("UserMedia", () => {
  extIn.dispose();
  });
  + it("properties return undefined before open", () => {
  + const extIn = new UserMedia();
  + expect(extIn.deviceId).to.be.undefined;
  + expect(extIn.groupId).to.be.undefined;
  + expect(extIn.label).to.be.undefined;
  + extIn.dispose();
  + });
  +
  it("indicates if the browser has UserMedia support", () => {
  expect(UserMedia.supported).to.be.a("boolean");
  });
  