Pytest Patch

An automagic replacement for monkeypatch or unittest.mock.patch that can be used on objects either directly or by name.

Usage

patching objects directly

from pytest import fixture
from mock import MagicMock, sentinel

from mymodule import callee, caller  # `caller` returns `callee()`


@fixture
def callee_mock(patch):
  # returns the second argument if provided, `MagicMock()` otherwise
  return patch(callee, MagicMock(return_value=sentinel.callee))


def test_caller(callee_mock):
  assert caller() == sentinel.callee

patching objects by name

@fixture
def callee_mock(patch):
  return patch('callee')  # assumes `callee` is in `mymodule`

patching by full path

This behavior is similar to unittest.mock.patch.

@fixture
def callee_mock(patch):
  return patch('mymodule.callee')

Configuration

By default, pytest-patch assumes the following repository structure:

mymodule/
  .git/
    ...
  mymodule/
    wat/
      ermelon.py
    ...
  tests/
    */  # e.g. unit/
      mymodule/
        wat/
          test_ermelon.py
    ...

No configuration is needed if your repository matches this structure where the repository name is the same as the name of the module and your tests are in their corresponding subdirectories mirroring your module's path structure.

If the above is not the case, e.g. you have a repository with a nonmatching module name or a monorepo with multiple modules, you may specify the corresponding flags either in the pytest command line or the ini file, glob-style:

pytest --module-names=mymodule,othermodule --test-paths=tests.unit,tests.e2e.*

or (in pytest.ini)

[pytest]
module_names = mymodule othermodule
test_paths = tests.unit tests.e2e.*