How to test ejs/nodejs function with mocha/chai?

Question

I have a function in a ejs/nodejs application that I need to test. The function adds a user(name and array of 4 letter grades). I want to test the function to verify that it adds one user.

the function:

router.addUsers = (req, res) => {
  console.log("in homeController addUser");

  var newUserName = req.body.name;
  console.log("name " + newUserName);
  var newUsergrade = req.body.grade;

  var temp = 0;
  newUsergrade.forEach(letter => {
    letter = letter.toUpperCase();
    switch (letter) {
      case 'A':
        letter = 4.0
        break
      case 'A-':
        letter = 3.7
        break
      case 'B+':
        letter = 3.3
        break
      case 'B':
        letter = 3.0
        break
      case 'B-':
        letter = 2.7
        break
      case 'C+':
        letter = 2.3
        break
      case 'C':
        letter = 2.0
        break
      case 'C-':
        letter = 1.7
        break
      case 'D+':
        letter = 1.3
        break
      case 'D':
        letter = 1.0
        break
      case 'F':
        letter = 0.0
        break
    }
    temp += letter;
  });

  var valid = false;

  if (temp / 4 >= 2.5) {
    valid = true;
  } else {
    vaild = false;
  }

  col.insertOne({
    name: newUserName,
    grade: newUsergrade,
    isValid: valid
  }, function(err, r) {
    test.equal(null, err);
    test.equal(1, r.insertedCount);
    col.find({}).toArray((err, userData) => {
      console.log("record found: ", userData);
      usersArray = userData;
    });

  });

  usersArray.push({
    name: newUserName
  });
  res.render("users", {
    allUsers: usersArray,
    title: "Users List"
  });
};

What I've been trying so far:

describe("addUsers", () => {
  it("should make sure a user can be added to the array", () => {
    var usersArray = {
      name: "blake",
      grade: ["a", "a", "b", "d"]
    };
    expect(router.addUsers(usersArray)).to.deep.include({
      name: "blake",
      grade: ["a", "a", "b", "d"]
    });
  });

  it("should return an empty object with empty request body input", () => {
    var emptyBody = {};
    expect(router.addUsers(emptyBody)).to.deep.include({});
  });
});

Im getting an error that 'name' is undefined. Could this be because of the req,res or the res.render?

Answer 1

    expect(router.addUsers(usersArray)).to.deep.include({
      name: "blake",
      grade: ["a", "a", "b", "d"]
    });

Your function returns undefined but here you're checking the return value includes name. That's why it says name is undefined.

You want something like the below, you could use some sort of package to mock the request and response objects more appropriately.

const fakeReq = { body: { name: 'something', grade: 'somethingElse' }},
  fakeRes = { render: () => {}};

await router.addUsers(fakeReq, fakeRes);

expect(usersArray).to.deep.include({ name: 'something' });