Angular Service Unit Testing - faking nested methods or not?

Question

I have very simple question.

If i have in one service methods like this one

generateObjectBasedOnName(name: string): SomeObject {
  if(this.isNameValid(name)) {
    const {namePart1, namePart2} = this.getNameParts(name);
    const baseObjectOne = this.getBaseObjectOne(namePart1);
    const baseObjectTwo = this.getBaseObjectTwo(namePart2);

    baseObjectOne.someDataNeededToSetHere = false;
    baseObjectTwo.someDataNeededToSetHere = true;

    return this.generateSomeObject(baseObjectOne, baseObjectTwo);
  }

  return null;
}

Should I, in unit tests, fake methods that are used in this method or should I just leave them to execute normally?

Thanks for any answers :)

Answer 1

The purpose of a unit test is to validate that a specific software unit (in your case that's your service class) performs as designed. Therefore...

• you must not mock individual methods of the unit under test.
• you should possibly mock methods of classes that are injected to the unit under test.