pytest-it

Decorate your pytest suite with RSpec-inspired markers describe, context and it. Then run pytest --it to see a plaintext, org-mode compatible spec of the test structure.

Install

pytest-it is available on PyPi: pip install pytest-it.

Examples

A basic example that uses pytest.mark.describe, pytest.mark.context and pytest.mark.it:

from pytest import mark as m

@m.describe("The test function report format")
class TestPytestItExample(object):

    @m.context("When @pytest.mark.it is used")
    @m.it("Displays an '- It: ' block matching the decorator")
    def test_it_decorator(self, testdir):
        pass

This produces:

- Describe: The test function report format...

  - Context: When @pytest.mark.it is used...
    - ✓ It: Displays an '- It: ' block matching the decorator

Describe and Context blocks can be nested arbitrarily by using multiple markers, eg:

from pytest import mark as m

@m.describe("The test function report format")
class TestPytestItExample(object):

    @m.context("When @pytest.mark.it is not used")
    @m.it("Displays the test function name")
    def test_no_argument(self, testdir):
        pass

    @m.context("When @pytest.mark.it is not used")
    @m.context("but the test name starts with 'test_it_'")
    @m.it("Prettifies the test name into the 'It: ' value")
    def test_populates_the_it_marker_using_function_name(self, testdir):
        pass

This produces:

- Describe: The test function report format...

  - Context: When @pytest.mark.it is not used...
    - ✓ It: Displays the test function name

    - ...but the test name starts with 'test_it_'...
      - ✓ It: Prettifies the test name into the 'It: ' value

Behaviour

• Pytest markers are used to specify the Describe:, Context: and It: sections. You can set these in all the usual ways that you specify pytest markers.
• Describe and Context can be nested arbitrarily.
• If --collect-only is used, it displays the same pytest-it spec as usual, but without the test result (✓/F/s).
• If -v is higher than 0, the full path to the test function is include in the test name.
• If pytest.mark.it is not used on a test, the test name is displayed instead of the It: does something output.
• If pytest.mark.it is not used but the test name starts with test_it, pytest-it will prettify the test name into an It: does something value.
• The test output should be able to be copied directly into an org-mode file.

Background

Pytest provides a lot of useful features for testing in Python, but when testing complex systems, it can be hard to clearly communicate the intent of a test using the standard test_module.py::TestClass::test_function structure.

One way to improve clarity is to use a BDD testing framework (eg. Behave, Mamba, Rspec), but it's not always desirable to restructure existing test and program code.

There are some pytest plugins that attempt to bridge this gap, by providing alternative ways to structure the tests (eg. pytest-describe, pytest-bdd), or altering the test report output (eg. pytest-testdox, pytest-pspec).

pytest-it takes a similar approach to pytest-testdox, by providing pytest markers that can describe the test output. pytest-it supports a few other features, such as:

• A plaintext test structure that can easily be copied to markdown/org-mode documents.
• Arbitrary nesting of describe and context markers.
• Supporting the --collect-only pytest flag to display test structure.
• Displaying the full path to each test if -v is used.
• Neatly integrating tests in the output if they don't use the pytest-it markers.

Although pytest-it does not change the behaviour of pytest tests, you may find it a useful tool for thinking about test structure, and communicating the intention of both the test code and the system under test.