Mock a library method response using pytest

Question

I am new to pytest, i want to create a test for a method called inside a library. So following is my sample usecase.

I have a python library called core:

• Inside core there is a folder called p_core.
• Inside p_core there is python file common.py
• In this common.py file, there is a class CommonBase, this class have following method

def get_timestamp(input_example):
  # I have an import statement in this file that is, import time
  timestamp = time.time()

  return f'{input_example}-{timestamp}'

So I want to mock the time.time(), because every time I don't want to get a different timestamp.

following is my pytest code

import time
from core.p_core.common import CommonBase


def test_get_timestamp(mocker):
    mock_now = mocker.patch("core.p_core.common.CommonBase.time.time",
                            return_value=1680087494.2400253)

    assert CommonBase.get_timestamp('TEST') == "TEST1680087494.2400253"

But I am getting an error ModuleNotFoundError: No module named core.p_core.common.CommonBase

Please ignore my get_timestamp methods logic, this is just an example.

Thank you.

Answer 1

The issue is solved by updating the test_get_timestamp method as follows.

def test_get_timestamp(mocker):
    mock_now = mocker.patch("core.p_core.common.time.time",
                            return_value=1680087494.2400253)

    assert CommonBase.get_timestamp('TEST') == "TEST1680087494.2400253"

mock_now = mocker.patch("core.p_core.common.time.time", return_value=1680087494.2400253) This was the change. Before I was patching core.p_core.common.CommonBase.time.time. But if we need to mock a method(in my example time.time()) that is imported in common.py(common.py is the file in the above example), then I have to pass this core.p_core.common.time.time for mocker.patch