Mock scope goes beyond current test

Question

I am mocking a module... here is my sample code

def test_validate(self):
    """Test Base Retriever Dataframe"""

    sampleQuoteClass = self.sampleQuoteClass('ThisQuote')

    bRet._getAsOfData = MagicMock(return_value=sampleQuoteClass)

    dataAsDataFrame = bVal.validate(metaDataName='MyNewQuote')
    self.assertTrue(len(dataAsDataFrame) > 0)

This works OK.

Problem is - bRet._getAsOfData is also mocked for the next tests, which incidentally resides in other test class.

This problem only occurs when all the tests are running together as a part of collection.

Answer 1

Sounds like you might want to patch the object instead of mocking it directly. You may need to adjust my example a bit to fit your code, but try something like this:

from mock import patch

def test_validate(self):
    """Test Base Retriever Dataframe"""

    sampleQuoteClass = self.sampleQuoteClass('ThisQuote')

    with patch('__main__.bRet') as mock_bRet:
        mock_bRet._getAsOfData.return_value = sampleQuoteClass

        dataAsDataFrame = bVal.validate(metaDataName='MyNewQuote')
        self.assertTrue(len(dataAsDataFrame) > 0)

When you patch the object, the mocking will be undone and the object will "go back to normal" once the with block exits, so the mocked state will not carry over to your other tests. It is also possible to use patch as a decorator, but I have always preferred to use it as a context manager. See the documentation linked above for examples of each usage.

Also, patching can be tricky in my experience, so I would suggest you read this useful bit of documentation on "where to patch" as well.