16

sample.py

def sum(num1, num2):
    return num1 + num2


def sum_only_positive(num1, num2):
    if num1 > 0 and num2 > 0:
        return num1 + num2
    else:
        return None

test_sample.py

from . import sample

import pytest

def test_sum():
    assert sample.sum(5, 5) == 10

def test_sum_positive_ok():
    assert sample.sum_only_positive(2, 2) == 4

def test_sum_positive_fail():
    assert sample.sum_only_positive(-1, 2) is None

Coverage command:

pytest test_sample.py --cov=sample.py

Error:

platform linux -- Python 3.5.2, pytest-5.4.1, py-1.8.1, pluggy-0.13.1
rootdir: /home/apathapa/unit_test/warriorframework_py3
plugins: cov-2.8.1
collected 3 items      

test_sample.py ...
[100%]Coverage.py warning: Module sample.py was never imported. (module-not-imported)
Coverage.py warning: No data was collected. (no-data-collected)
WARNING: Failed to generate report: No data to report.

/home/apathapa/ut/lib/python3.5/site-packages/pytest_cov/plugin.py:254: 
PytestWarning: Failed to generate report: No data to report.

  self.cov_controller.finish()


----------- coverage: platform linux, python 3.5.2-final-0 -----------
Name    Stmts   Miss  Cover
---------------------------


========= 3 passed in 0.13s =========

Can anyone help me how to resolve this error?

M. Hamza Rajput
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Anilkumar Pathapati
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3 Answers3

42

--cov accepts either directories or package names, not single files. This means that --cov=sample.py looks for a package (directory) named sample and inside it, a module (file) named py.py to record coverage, and fails. Either use

$ pytest --cov=sample

or

$ pytest --cov=.
hoefling
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  • I got this error just by including a forward slash(`/`) after the directory name like this: `pytest --cov=sample/`. So, if anyone is facing this issue, just remove the forward slash. – Eyong Kevin Enowanyo Aug 05 '21 at 09:01
3

Had the same issue, and got solved by running: coverage run -m pytest .

Xiu Yan Xin
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    Your answer could be improved with additional supporting information. Please [edit] to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers [in the help center](/help/how-to-answer). – Community Sep 23 '21 at 02:56
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    Please add some explanation to your code. – Muhammedogz Sep 23 '21 at 08:31
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    This worked for me - thank you for your answer. Afterward, I ran `coverage report -m` to print the report to the console – Benjamin Luo Apr 14 '22 at 02:24
3

Rename test files as 'test_' in order to run the below command.

pytest --cov=<package (directory) or module (file)>

Example: Suppose we have two files in a directory:

  1. sample.py: contains Python code
  2. test_sample.py: contains unit tests for sample.py then coverage command should be:

pytest --cov=sample

Akshay Rajguru
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