message: checking that the listener exists
diff: @@ -20,6 +20,7 @@ describe("Context", () => {
  const ctxTransport = context.transport;
  expect(context.destination).is.instanceOf(Destination);
  expect(context.draw).is.instanceOf(Draw);
  + expect(context.listener).to.exist;
  await context.close();
  expect(ctxDest.disposed).to.be.true;
  expect(ctxDraw.disposed).to.be.true;
  