CODEWITHSUNDEEP
pythonpytest
jacobcan118
jacobcan118

Reputation: 9037

Provide default argument value for py.test fixture function

Is there a better way for me to provide default value for argument pytest.fixture function?

I have a couple of testcases that requires to run fixture_func before testcase and I would like to use default value for argument in fixture if none of them is provided. The only code I can come up with is as follows. Any better way for me to do it?

@pytest.fixture(scope="function")
def fixture_func(self, request):
    argA = request.param['argA'] if request.param.get('argA', None) else 'default value for argA'
    argB = request.param['argB'] if request.param.get('argB', None) else 'default value for argB'
    # do something with fixture

@pytest.mark.parametrize('fixture_func', [dict(argA='argA')], indirect=['fixture_func'])
def test_case_1(self, fixture_func):
    #do something under testcase
    pass

@pytest.mark.parametrize('fixture_func', [dict()], indirect=['fixture_func'])
def test_case_2(self, fixture_func):
    #do something under testcase
    pass

i wna to use as

def test_case_3(self, fixture_func):
    #do something under testcase
    pass

Upvotes: 3

Views: 8559

Answers (3)

Michał Zawadzki
Michał Zawadzki

Reputation: 752

Below is a full example that worked for me. It was quite hard to figure out the required type of the params arg, as well as which type request takes in which situation (it changes depending on what you pass to pytest.mark.parametrize(), and it's also different if you don't use it, ie. use default params).

@pytest.fixture(params=[({'arg1': 1}, {'arg2': 2})])
def my_fixture(request):
    if isinstance(request.param, tuple):
        arg1 = request.param[0]["arg1"]
        arg2 = request.param[1]["arg2"]
    else:
        arg1 = request.param["arg1"]
        arg2 = request.param["arg2"]
    return arg1 + arg2

This way (and this way only), I was able to use both the default params, as well as specify overrides when needed. For example:

a) no overrides

def my_test(my_fixture):
    print(my_fixture)
    # >>> 3

b) with overrides

@pytest.mark.parametrize(
    "my_fixture",
    [
        (
            {
                "arg1": 3,
                "arg2": 4,
            }
        )
    ],
    indirect=True,
)
def my_test(my_fixture):
    print(my_fixture)
    # >>> 5

Upvotes: 0

Mahdi Shafiei
Mahdi Shafiei

Reputation: 41

Add params to your fixture:

@pytest.fixture(scope='function', params=[{'arg1': 'default'}, {'arg2': 'default'}])
def my_fixture(request):
    return request.param['arg1'] + request.param['arg1']

Upvotes: 4

Latrova
Latrova

Reputation: 493

None is the default result

request.param.get('argA', None)

So, you can just:

argA = request.param.get('argA', 'default value for argA')

Upvotes: 2

Related Questions