I am dealing with an issue of generation coverage which does not work as expected. Finally I found out it's somehow connected to pydevd (PyDev debugger) package.
To reproduce my issue you can use following repo: cov-project
There are only two files. One in my_package with
import pydevd # Just for the purpose to show the problem
def sum(num1, num2):
return num1 + num2
def mult(num1, num2):
return num1 * num2
And the test file test_math.py in tests:
from my_package.math import sum, mult
def test_sum():
assert sum(1, 2) == 3
def test_mult():
assert mult(2, 3) == 6
When I remove import pydevd from the first file and run python -m pytest --cov=my_package tests I get this output:
Name Stmts Miss Cover
--------------------------------------------
my_package/__init__.py 0 0 100%
my_package/math.py 4 0 100%
--------------------------------------------
TOTAL 4 0 100%
Yes, 100% coverage as expected. But when I run the same and keeping importing pydevd I get:
Name Stmts Miss Cover
--------------------------------------------
my_package/__init__.py 0 0 100%
my_package/math.py 5 4 20%
--------------------------------------------
TOTAL 5 4 20%
The testing is completely same, the only change is this additional import. Of course, in this setup pydevd is unused and I can simply remove it. But I use it in my proprietary code so I wanted to show the simplest way how to reproduce my error since I cannot generate appropriate coverage report when using pydevd. I could change it to local import as I do not use it in my tests, then it would work, but I'm trying to understand what is happening here and why would pydevd prevent coverage from successful report generation.
Tested:
This was really a bug in pydevd.
I've fixed it in https://github.com/fabioz/PyDev.Debugger/commit/be32cd821f2574566385deeec23081365bf16722
You can apply the same fix to your local version in the meanwhile.
To find out the file for the fix you can do:
import pydevd
from _pydevd_bundle import pydevd_constants
print(pydevd_constants.__file__)