tests: fix checkstyle-python
Add --check to black to pass back error value and fail checkstyle if
a reformat would occur.
Type: fix
Fixes:
@@ -351,7 +351,7 @@ start-gdb: sanity
.PHONY: checkstyle-python-all
checkstyle-python-all: $(PIP_INSTALL_DONE)
@bash -c "source $(VENV_PATH)/bin/activate &&\
- black -t py39 --diff $(WS_ROOT) ||\
+ black -t py39 --check --diff $(WS_ROOT) ||\
(echo \"*************************************************************************\" &&\
echo \"* Test framework PEP8 compliance check FAILED (maybe: make fixstyle-python)\" &&\
echo \"*************************************************************************\" &&\
