ISBN Validator, built this to practice Test Driven Development (TDD)
I followed the Lynda Course "Practical Test-Driven Development for Java Programmers" by Matt Greencroft.
This is only a tiny test project, but it did help me understand the benefits and the workflow of TDD.
- JUnit
- Mockito.
- Red -> Green -> Refactor
- Start with Red to make sure that the new test executes as expected
- To get to Green: Only write the minimum amount of code to make all tests pass (even if you know it’s wrong in the long run)
- Refactor to remove redundancy
- Each Test must check one single peace of logic
- Only more then one assert() in a test when the same logic is tested with multiple values
- Test Business-Logic, not methods
- Tests must be repeatable
- What should the Logic be? (Whats a 10 Digit ISBN?)
- What is the opposite of that Logic? (Which Numbers are not Valid ISBN?)
- Are there Edge-Cases? (What about ISBN that end in X?)
- ERROR Conditions? (When are we throwing ERRORs?)
| Type | What is it for? | In Mockito |
|---|---|---|
| Fake | No Test | mock() |
| Stub | Test Data | mock() when().thenReturn() |
| Mock | Test Behaviour | mock() verify().myMethod() |
