Limit to the worst tests

Author: chrahunt

tools/requirements/tests.txt

@@ -3,6 +3,7 @@ mock
 pretend
 pytest==3.8.2
 pytest-cov
+pytest-custom_exit_code
 # Prevent installing 7.0 which has install_requires "pytest >= 3.10".
 pytest-rerunfailures<7.0
 pytest-timeout

tox.ini

@@ -20,7 +20,7 @@ deps = -r{toxinidir}/tools/requirements/tests.txt
 commands_pre =
 	python -c 'import shutil, sys; shutil.rmtree(sys.argv[1], ignore_errors=True)' {toxinidir}/tests/data/common_wheels
 	{[helpers]pip} wheel -w {toxinidir}/tests/data/common_wheels -r {toxinidir}/tools/requirements/tests-common_wheels.txt
-commands = pytest --timeout 300 []
+commands = pytest --timeout 300 --suppress-no-test-exit-code [] tests/unit/test_build_env.py
 install_command = {[helpers]pip} install {opts} {packages}
 list_dependencies_command = {[helpers]pip} freeze --all