Two files using supertest with mocha causing EADDRINUSE

Question

I'm using supertest to unit test my server configurations and route handlers. The server configurations tests are in test.server.js and the route handling tests are in test.routes.handlers.js.

When I run all the test files using mocha ., I get EADDRINUSE. When I run each file individually, everything works as expected.

Both files define and require supertest, request = require('supertest'), and the express server file, app = require('../server.js'). In server.js, the server is started like so:

http.createServer(app).listen(app.get('port'), config.hostName, function () {
  console.log('Express server listening on port ' + app.get('port'));
});

Is there something wrong in my implementation? How can I avoid EADDRINUSE error when running my tests?

Answer 1

mocha has a root Suite:

You may also pick any file and add "root" level hooks, for example add beforeEach() outside of describe()s then the callback will run before any test-case regardless of the file its in. This is because Mocha has a root Suite with no name.

We use that to start an Express server once (and we use an environment variable so that it runs on a different port than our development server):

before(function () {
  process.env.NODE_ENV = 'test';
  require('../../app.js');
});

(We don't need a done() here because require is synchronous.) This was, the server is started exactly once, no matter how many different test files include this root-level before function.

Try requiring supertest from within a root level before function in each of your files.

Answer 2

Answering my own question:

My supertest initialization looks like this:

var app = require('../server.js');
var request = require('supertest')(app);

In test.server.js, I had these require statements directly inside a describe. In test.routes.handlers.js, the statements were inside a before inside a describe.

After reading dankohn's answer, I was inspired to simply move the statements to the very top outside any describe or before and the tests all run without problems now.