title: Mocha before doesn't let me go next
body: <p>I have a problem with mocha tests, i'am trying to make  initial setup to make some tests. Unfortunately i have no idea why mocha doesn't show me any errors. Promise.all is working correctly and shows me results but it doesn't let me go to the next step -> tests.</p>
  
  <p>It is working if only i remove second promise (createCourseAndReview) and all tests pass (i mean it's executing tests).</p>
  
  <pre><code>before(() =&gt; {
    return new Promise((resolve, reject) =&gt; {
      const createUser = User.remove({}, function(err) {
        if (err) {
          console.log(err);
          return Promise.reject();
        }
        User.create({
          googleId: "googleId",
          name: "name",
          email: "email@email.com",
          phone: "000000000"
        })
          .then(res =&gt; {
            token = createToken({ googleId: res.googleId });
            return Promise.resolve();
          })
          .catch(err =&gt; {
            console.log(err);
            return Promise.reject();
          });
      });
      const createCourseAndReview = Course.remove({}, function(err) {
        if (err) {
          return Promise.reject();
        }
        Course.create({
          title: "Tytuł",
          shortTitle: "Krótki tytuł",
          video: {
            link: "http://",
            title: "Tytuł",
            shortDescription: "video desc"
          },
          content: "zawartość",
          image: "gosc.jpg",
          duration: "2 tygonie",
          price: "120zł/h",
          shortDescription: "Krótki opis",
          technologies: ["Java", "Javascript"],
          maxMembers: "12/12",
          reviews: [],
          comments: []
        })
          .then(doc =&gt; {
            Course.update(
              { _id: doc._id },
              {
                $push: {
                  reviews: {
                    content: "Zawartość",
                    grade: 5,
                    user: {
                      googleId: "googleId",
                      name: "name",
                      email: "email@email.com",
                      phone: "000000000"
                    }
                  }
                }
              }
            ).then(() =&gt; {
              return Promise.resolve();
            });
          })
          .catch(err =&gt; {
            console.log(err);
            return Promise.reject();
          });
      });
  
      Promise.all([createUser, createCourseAndReview])
        .then(results =&gt; {
          console.log(results);
          resolve();
        })
        .catch(err =&gt; {
          console.log(err);
          reject();
        });
    });
  });
  </code></pre>
  
  <p>I don't get any errors and i don't know how to resolve this kind of issue.</p>