CODEWITHSUNDEEP
pythonunit-testingintegration-testingpytesttdd
Athena Wisdom
Athena Wisdom

Reputation: 6871

Testing Two Classes With Each Other in Pytest

I just started learning about writing unit tests with pytest but I cannot find anything about testing to check if 2 classes work properly together where one class takes the output of the second class, such as

assert bar.bar(foo.foo('hello')) == 'hellofoobar'

Should pytest be used for running such tests that involve 2 classes? If so, should this test be written in test_foo.py or test_bar.py?

Will such a test be known as integration tests?

Foo.py

class Foo:
    def foo(self, x):
        return f'{x}foo'

Bar.py

class Bar:
    def bar(self, x):
        return f'{x}bar'

conftest.py

import pytest

from .Foo import Foo
from .Bar import Bar

@pytest.fixture
def foo():
    return Foo()

@pytest.fixture
def bar():
    return Bar()

test_foo.py

def test_foo(foo):
    assert foo.foo('hello') == 'hellofoo'

test_bar.py

def test_bar(bar):
    assert bar.bar('world') == 'worldbar'

__init__.py

Upvotes: 1

Views: 395

Answers (1)

Marcel Wilson
Marcel Wilson

Reputation: 4572

I think this is perfectly fine. It expects that both Foo and Bar are working properly. In that case, I think you could call it an integration test.

test_bar.py

def test_bar_with_foo(bar, foo):
    assert bar.bar(foo.foo('hello')) == 'hellofoobar'

The need for this type of test might depend on how complex each class is. In the stated case (which is super simple) I think it would be ok to get away with breaking up the tests; meaning if test_bar.test_bar passes and test_foo.test_foo passes then test_bar.test_bar_with_foo becomes redundant.

If we break down the test and assume Foo returns the correct thing the test starts to look something like the below. At which point the question arises; does this test provide further value beyond test_bar.test_bar?

test_bar.py

def test_bar_2(bar):
    assert bar.bar('hellofoo') == 'hellofoobar'

Upvotes: 1

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