app

flask-test-kata

CREDIT: https://github.com/plain-vanilla-games/flask-test-kata

This is a python testing kata for a simple Flask web "service".

This project has the following skeleton:

app
├── calculator
│   ├── __init__.py
│   ├── app.py
│   ├── logic.py
│   └── templates
│       └── index.html
├── README.md
├── requirements.txt
└── tests
    ├── __init__.py
    ├── base.py
    ├── integration
    |   ├── __init__.py
    |   └── test_views.py
    └── unit
        ├── __init__.py
        └── test_logic.py

The tasks at hand:

Unit Tests

1. Implement test_mul unit test for the multiply method in logic.Calculator, then flesh out logic.Calculator.mul until test passes.

2. test_mul as a test is rather coarse. A better test would be in the form test_function_satisfies_condition_after_pre-condition. Implement the tests test_mul_with_two_positive_numbers, test_mul_with_two_negative_numbers, test_mul_with_one_negative_one_positive_number.

3. The constructor of logic.Calculator takes two arguments min_value and max_value. Change the class so that it's methods throw the exceptions in logic.py when confronted with numbers that are too high or too low.

4. Make sure to add tests to check the boundary of min_value and max_value.

5. logic.Calculator contains another method stub: div. This method should divide a by b, but it is just a stub now. Write corresponding tests for the method, as you've written for logic.Calculator.mul, then implement the method to pass your tests.

6. Division has more caveats than multiplication. Python will raise an exception of type ZeroDivisionError when you attempt to divide by zero, write a test asserts that your Calculator class does not suppress them.

The preferred way of testing whether exceptions are raised is to use

with pytest.raises(MyException):
    code...

Integration Tests

1. If by now the multiplication logic has been correctly implemented, the test_multiply integration test should be passing. Implement integration tests which verify the responses for valid and invalid inputs (think about the boundaries of max and min values).

2. Write corresponding integration tests for the /div view

3. Make sure that for requests that attempt to divide by zero that the calculator app returns an appropriate 403 response.