From fa5500228e82f46b72191e747cf3b3fd15c4da0d Mon Sep 17 00:00:00 2001
From: "Andrew J. Hesford" <ajh@sideband.org>
Date: Mon, 7 Jun 2021 23:41:26 -0400
Subject: [PATCH] build-style/python3-{module,pep517}.sh: improve pytest usage

1. Relying on `python3 -m pytest --help` to test for pytest can fail
   because the pytest packages's __main__ is still invoked; this can
   trigger import problems and falsely indicate that pytest is missing.
   A simpler test is to just confirm that pytest is importable. If so,
   the interpreter returns 0. Otherwise, an ImportError is thrown and
   the interpreter will return 1.

2. Many templates require a custom do_check just to set PYTHONPATH to
   either a build directory (especially for compiled extensions) or some
   subdirectory of the source tree. Setting PYTHONPATH automatically to
   the build directory should drastically reduce the need for custom
   do_check in py3 templates. (This only applies to python3-module.sh
   because pep517 builders will have unpredictable build directories.)

Closes: #31354.
---
 common/build-style/python3-module.sh | 5 +++--
 common/build-style/python3-pep517.sh | 2 +-
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/common/build-style/python3-module.sh b/common/build-style/python3-module.sh
index ad5fdff252..093bdae8a0 100644
--- a/common/build-style/python3-module.sh
+++ b/common/build-style/python3-module.sh
@@ -24,8 +24,9 @@ do_build() {
 }
 
 do_check() {
-	if python3 -m pytest --help >/dev/null 2>&1; then
-		python3 -m pytest ${make_check_args} ${make_check_target}
+	if python3 -c 'import pytest' >/dev/null 2>&1; then
+		PYTHONPATH="$(cd build/lib* && pwd)" \
+			python3 -m pytest ${make_check_args} ${make_check_target}
 	else
 		# Fall back to deprecated setup.py test orchestration without pytest
 		if [ -z "$make_check_target" ]; then
diff --git a/common/build-style/python3-pep517.sh b/common/build-style/python3-pep517.sh
index 4051185a28..075f954a1a 100644
--- a/common/build-style/python3-pep517.sh
+++ b/common/build-style/python3-pep517.sh
@@ -13,7 +13,7 @@ do_build() {
 }
 
 do_check() {
-	if python3 -m pytest --help >/dev/null 2>&1; then
+	if python3 -c 'import pytest' >/dev/null 2>&1; then
 		python3 -m pytest ${make_check_args} ${make_check_target}
 	else
 		msg_warn "Unable to determine tests for PEP517 Python templates"