CODEWITHSUNDEEP
jsonpython-3.xpandasunit-testingmocking
shan
shan

Reputation: 583

mocking a file within a function

I have written the following function :

def get_env_id(id):
    with open(pathlib.Path(__file__).parent / 'srm.json') as file:
        data = json.load(file)
        return data.get(id)

I am performing unit test on the above function. I want to mock the file within the function with some json file. The json file content is as follows:

{"id":{"0":1,"1":2,"2":3},"value":{"0":20,"1":30,"2":40}}

Upvotes: 0

Views: 336

Answers (1)

funnydman
funnydman

Reputation: 11346

You can use mock_open from unnitest package, something like:

from unittest.mock import patch, mock_open

BASE_PATH = pathlib.Path(__file__).parent

MOCK_DATA = {"id": {"0": 1, "1": 2, "2": 3}, "value": {"0": 20, "1": 30, "2": 40}}


def get_env_id(id):
    with open(BASE_PATH / 'srm.json') as file:
        data = json.load(file)
        return data.get(id)


@patch("builtins.open", new_callable=mock_open, read_data=json.dumps(MOCK_DATA))
def test_get_env_id(mock_file):
    id = get_env_id("id")
    assert id == {"0": 1, "1": 2, "2": 3}
    mock_file.assert_called_once()
    mock_file.assert_called_with(BASE_PATH / 'srm.json')

Upvotes: 1

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