问题 I've been at this problem for a while and I cannot make the existing solutions work for me. I have a Node.js API written in Express.js. I have been writing tests for the API using Mocha, Chai, and Supertest. These test are mostly integration tests. One test may look like: it('should fail to register a new user without the proper information', function(done) { api.post('/user') .send({}) .expect(400) .expect('Content-Type', /json/) .end(function(err, res) { should.exist(res.body); should.exist