pytest gives "Coverage disabled via --no-cov switch!" warning even --no-cov is not given!!

• a detailed description of the bug or suggestion I have not set --no-cov in any cli or configs, but it is given me the warning “Coverage disabled via --no-cov switch!”. Even worse, I have enabled coverage in pytest.ini:

[pytest]
addopts = --cov=mypackage -vvv -s

But coverage is not running!

Here is output:

(ENV) $ python -m pytest
=================================================== test session starts ====================================================
platform darwin -- Python 2.7.15, pytest-4.4.1, py-1.8.0, pluggy-0.9.0 -- /Users/local/myrepo_new/ENV/bin/python
cachedir: .pytest_cache
rootdir: /Users/local/myrepo_new, inifile: pytest.ini
plugins: cov-2.6.1
collected 1 item                                                                                                           

test/test_myrepo.py::test_x PASSED
WARNING: Coverage disabled via --no-cov switch!

===================================================== warnings summary =====================================================
ENV/lib/python2.7/site-packages/pytest_cov/plugin.py:253
  /Users/local/myrepo_new/ENV/lib/python2.7/site-packages/pytest_cov/plugin.py:253: PytestWarning: Coverage disabled via --no-cov switch!
    warnings.warn(pytest.PytestWarning(message))

-- Docs: https://docs.pytest.org/en/latest/warnings.html
=========================================== 1 passed, 1 warnings in 0.03 seconds ===========================================

• output of pip list from the virtual environment you are using

(ENV)$ pip list
DEPRECATION: Python 2.7 will reach the end of its life on January 1st, 2020. Please upgrade your Python as Python 2.7 won't be maintained after that date. A future version of pip will drop support for Python 2.7.
Package        Version
-------------- -------
atomicwrites   1.3.0  
attrs          19.1.0 
coverage       4.5.3  
funcsigs       1.0.2  
more-itertools 5.0.0  
pathlib2       2.3.3  
pip            19.1   
pluggy         0.9.0  
py             1.8.0  
pytest         4.4.1  
pytest-cov     2.6.1  
scandir        1.10.0 
setuptools     41.0.1 
six            1.12.0 
wheel          0.33.1 

• pytest and operating system versions

(ENV) $ pytest --version
This is pytest version 4.4.1, imported from /Users/local/myrepo_new/ENV/lib/python2.7/site-packages/pytest.pyc
setuptools registered plugins:
  pytest-cov-2.6.1 at /Users/local/myrepo_new/ENV/lib/python2.7/site-packages/pytest_cov/plugin.py
(ENV)$ plutil -p /System/Library/CoreServices/SystemVersion.plist
{
  "iOSSupportVersion" => "12.0"
  "ProductBuildVersion" => "18D25"
  "ProductCopyright" => "1983-2018 Apple Inc."
  "ProductName" => "Mac OS X"
  "ProductUserVisibleVersion" => "10.14.3"
  "ProductVersion" => "10.14.3"
}

• minimal example if possible myrepo_new.zip

[ssbarnea]

Presence of --no-cov switch should just silence the warning because that is the only way a developer can disable coverage on project having them without altering the codebase. The project itself may have pycov parameters mentioned in its tox.ini or pytest.ini files but once the use defines PYTEST_ADDOPTS, this will take precedence over other options.

I hope that this explains the reasoning behind silencing the warning, as it is just noise. Maybe another approach would be to make a a DEBUG level message, so it will not appear on normal executions.

[ssbarnea]

I am facing the same annoying warning when I have PYTEST_ADDOPTS='-s --maxfail=10 --no-cov' and when running pytest, I get 7 extra lines of warnings which are useless. If user mentions that he does not want coverage, there is no reason to throw any warnings.

WARNING: Coverage disabled via --no-cov switch!
================================================================================= warnings summary ==================================================================================
/Users/ssbarnea/.pyenv/versions/3.6.8/lib/python3.6/site-packages/pytest_cov/plugin.py:253
  /Users/ssbarnea/.pyenv/versions/3.6.8/lib/python3.6/site-packages/pytest_cov/plugin.py:253: PytestWarning: Coverage disabled via --no-cov switch!
    warnings.warn(pytest.PytestWarning(message))

-- Docs: https://docs.pytest.org/en/latest/warnings.html

Environment should just take precedence over values configured in pytest.ini.