I've found the reason for my problem. I've created the mock in my test class tried to test my rest api with supertest. The problem was that the test was executed in another process as the process in that my webserver runs. I've created the express-app in my test class and the test is now green.
this is test
describe('When user wants to list all existing pages', function () {
var sandbox;
var app = express();
beforeEach(function (done) {
sandbox = sinon.sandbox.create(); // @deprecated — Since 5.0, use sinon.createSandbox instead
app.get('/api/pages', pagesRoute);
done();
});
afterEach(function (done) {
sandbox.restore();
done();
});
it('should return a list of the pages with their titles except the index page', function (done) {
sandbox.stub(fs, 'readdir', function (path, callback) {
callback(null, ['index.md', 'page1.md', 'page2.md']);
});
request(app).get('/api/pages')
.expect('Content-Type', "application/json")
.expect(200)
.end(function (err, res) {
if (err) {
return done(err);
}
var pages = res.body;
should.exists(pages);
pages.length.should.equal(2);
done();
});
});
});