Async code calls MyStore.listen() twice.

[mintuz]

Hello, I've come across an issue where MyStore.listen() will get called twice in my unit tests/production code if I use async code within the store. Here is my store code, the apiResolver is just a light wrapper on top of axios.

tryRegister: function(registerObj) {
    apiResolver.registerUser({
      email: registerObj.email,
      password: registerObj.password,
      platform: 'app'
    })
    .then(function() {
      this.setState({error: false, registered: true});
    }.bind(this))
    .catch(function(error) {
      this.setState({error: {title: 'Registration Failure', message: error.data}});
    }.bind(this));
  }

Unit test code

it.only('if successfully registered, set state object registered to true', function(done) {

      // Given
      var apiResolverMock = {
        registerUser: sinon.stub().returns(Promise.resolve(true))
      };

      resetRewires.push(rewiredAuth.__set__('apiResolver', apiResolverMock));

      AuthStore.listen(function(state) {
        console.log(state);
        expect(state.registered).to.equal(true);
        done();
      });

      expect(AuthStore.state.registered).to.equal(false);

      // When
      AuthActions.tryRegister({
        email: 'email@example.com',
        password: 'password'
      });

    });