From 7355149b2c27332697e27d39f53917a8689db2d2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Luk=C3=A1=C5=A1=20Vokr=C3=A1=C4=8Dko?= <lukas@vokracko.cz>
Date: Wed, 29 Apr 2026 14:10:37 +0200
Subject: [PATCH] build: measure coverage on source only via coverage run

The previous setup relied on pytest-cov (``--cov pytest_split
--cov tests`` in addopts) which has a long-standing limitation when
measuring a pytest plugin: the plugin imports happen during pytest's
plugin discovery, *before* pytest-cov starts tracing. Anything that
runs at import time (class bodies, decorators, type aliases, enum
definitions) is reported as uncovered even though it obviously
executed - the plugin wouldn't load otherwise. The
``CoverageWarning: Module pytest_split was previously imported, but
not measured`` made that explicit.

The cookiecutter template the project was generated from worked
around this by adding ``--cov tests`` to the addopts, inflating the
denominator with 100%-covered test files so the average reached 90%.
That pulled the number up but stopped reporting the actual source
coverage.

Switch to ``coverage run -m pytest`` followed by ``coverage report``.
Running ``coverage`` from the outside means tracing starts before
Python imports anything at all, so plugin import-time code is
counted. Real source coverage jumps from ~74% to 99%; threshold goes
from 90 to 95 to reflect that.
---
 .github/workflows/test.yml |  3 ++-
 pyproject.toml             | 12 ++++--------
 2 files changed, 6 insertions(+), 9 deletions(-)

diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index f2dbbdd..505b3ad 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -44,7 +44,8 @@ jobs:
       - uses: ./.github/actions/python-poetry-env
         with:
           python-version: ${{ matrix.python-version }}
-      - run: poetry run pytest
+      - run: poetry run coverage run -m pytest
+      - run: poetry run coverage report
 
   docs:
     runs-on: ubuntu-latest
diff --git a/pyproject.toml b/pyproject.toml
index be14d7d..164e854 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -63,16 +63,12 @@ pytest-split = "pytest_split.plugin"
 target-version = ["py310", "py311", "py312", "py313", "py314"]
 include = '\.pyi?$'
 
-[tool.pytest.ini_options]
-addopts = """\
-    --cov pytest_split \
-    --cov tests \
-    --cov-report term-missing \
-    --no-cov-on-fail \
-"""
+[tool.coverage.run]
+source = ["pytest_split"]
 
 [tool.coverage.report]
-fail_under = 90
+fail_under = 95
+show_missing = true
 exclude_lines = [
     'if TYPE_CHECKING:',
     'pragma: no cover'