Try out coverage instead of pytest-cov

.coveragerc

@@ -1,14 +1,14 @@
 [run]
 branch=True
 source=trio
-# For some reason coverage recording doesn't work for ipython_custom_exc.py,
-# so leave it out of reports
 omit=
   setup.py
-  */ipython_custom_exc.py
+# These are run in subprocesses, but still don't work. We follow
+# coverage's documentation to no avail.
+  */trio/_core/_tests/test_multierror_scripts/*
 # Omit the generated files in trio/_core starting with _generated_
   */trio/_core/_generated_*
-# script used to check type completeness that isn't run in tests
+# Script used to check type completeness that isn't run in tests
   */trio/_tests/check_type_completeness.py
 # The test suite spawns subprocesses to test some stuff, so make sure
 # this doesn't corrupt the coverage files

ci.sh

@@ -109,12 +109,19 @@ else
     # get mypy tests a nice cache
     MYPYPATH=".." mypy --config-file= --cache-dir=./.mypy_cache -c "import trio" >/dev/null 2>/dev/null || true
 
-    if pytest -r a -p trio._tests.pytest_plugin --junitxml=../test-results.xml --run-slow ${INSTALLDIR} --cov="$INSTALLDIR" --cov-report=xml --cov-config=../.coveragerc --verbose; then
+    # support subprocess spawning with coverage.py
+    echo "import coverage; coverage.process_startup()" | tee -a "$INSTALLDIR/../sitecustomize.py"
+
+    if COVERAGE_PROCESS_START=$(pwd)/../.coveragerc coverage run --rcfile=../.coveragerc -m pytest -r a -p trio._tests.pytest_plugin --junitxml=../test-results.xml --run-slow ${INSTALLDIR} --verbose; then
         PASSED=true
     else
         PASSED=false
     fi
 
+    coverage combine --rcfile ../.coveragerc
+    coverage report -m --rcfile ../.coveragerc
+    coverage xml --rcfile ../.coveragerc
+
     # Remove the LSP again; again we want to do this ASAP to avoid
     # accidentally breaking other stuff.
     if [ "$LSP" != "" ]; then

test-requirements.in

@@ -1,6 +1,6 @@
 # For tests
 pytest >= 5.0         # for faulthandler in core
-pytest-cov >= 2.6.0
+coverage >= 7.2.5
 async_generator >= 1.9
 pyright
 # ipython 7.x is the last major version supporting Python 3.7

test-requirements.txt

@@ -26,8 +26,8 @@ click==8.1.3
     # via
     #   black
     #   pip-tools
-coverage[toml]==7.2.7
-    # via pytest-cov
+coverage==7.2.7
+    # via -r test-requirements.in
 cryptography==39.0.2
     # via
     #   -r test-requirements.in
@@ -121,10 +121,6 @@ pyproject-hooks==1.0.0
 pyright==1.1.310
     # via -r test-requirements.in
 pytest==7.3.1
-    # via
-    #   -r test-requirements.in
-    #   pytest-cov
-pytest-cov==4.1.0
     # via -r test-requirements.in
 sniffio==1.3.0
     # via -r test-requirements.in
@@ -134,7 +130,6 @@ tomli==2.0.1
     # via
     #   black
     #   build
-    #   coverage
     #   mypy
     #   pylint
     #   pytest

trio/_core/_tests/test_multierror.py

@@ -451,7 +451,11 @@ def run_script(name, use_ipython=False):
     print("subprocess PYTHONPATH:", env.get("PYTHONPATH"))
 
     if use_ipython:
-        lines = [script_path.read_text(), "exit()"]
+        lines = [
+            "import runpy",
+            f"runpy.run_path(r'{script_path}', run_name='trio.fake')",
+            "exit()",
+        ]
 
         cmd = [
             sys.executable,

trio/_core/_tests/test_multierror_scripts/apport_excepthook.py

@@ -1,3 +1,5 @@
+import _common
+
 # The apport_python_hook package is only installed as part of Ubuntu's system
 # python, and not available in venvs. So before we can import it we have to
 # make sure it's on sys.path.