Function wrapperFor

tests/unit/server.js:59–64

        // `sinon` matcher to match when the callback argument actually invokes the expected
        // function
        const wrapperFor = expected => sinon.match(actual => {
            const req = uuid.v4();
            const res = uuid.v4();
            actual(req, res);
            return expected.calledWith(req, res);
        });

        it('should start API server with default port if no listenOn is provided', async () => {
            config.port = 8000;