postfix 0.0.4

A Python package to facilitate writing tests for a testless code base.

postfix

A Python package to facilitate writing tests for a testless code base.

Installation

pip install --upgrade postfix

Usage

Suppose you have some tremendously complex code, but no tests for that code. But you are sufficiently convinced, that right now, it's working as it should. You want to do some refactoring, but you don't dare to do so without tests (wise decision!). So you decide to write tests a posteriori to make sure that after refactoring, the code works as before. Let's suppose that we want to create tests for the function myfunc and the method MyClass.mymethod (see example/state_1). And let's suppose that it is complicated to get realistic data for the arguments of that function/method. In order to quickly get a first test coverage with realistic input and output data, we will use postfix to create test fixtures. Annotate the function or method for which you create a fixture with the decorator postfix.create_fixture (see example/state2) and run your code. Remove the decorators from the production code, move the dumped fixture files to your newly created test suite directory and use them to write tests (see examples/state_3).

Limitations

In postfix you cannot instrument methods or functions that are located in the main module. However, for any nontrivial project with more than one Python file this should not be a limitation.