Change run-with function to error instead of warn

The 'make test' command will now error when dependencies are not
installed.

For py.test I made it use a virtualenv install of py.test and requests
modules. The Makefile looks for a Python 3 binary and errors otherwise.

I had python3 installed locally but not py.test. I didn't feel like that
should stop me from installing it temporarily on the fly like we do for
bpan.

Author: ingydotnet

.gitignore

@@ -1,3 +1,4 @@
 /.bpan/
+/.venv/
 /tests/__pycache__/
 /__pycache__/

.setup.mk

@@ -6,9 +6,14 @@ SHELL := bash
 define run-with
 $(if $(shell command -v $1), \
 $3, \
-$(warning WARNING: Can't 'make $2'. No '$1' command found.))
+$(error ERROR: Can't 'make $2'. No '$1' command found.))
 endef
 
 ifeq (,$(shell git diff --stat))
 GIT_STATUS_IS_CLEAN := 1
 endif
+
+PYTHON := $(shell command -v python3 || command -v python)
+ifeq (,$(and $(PYTHON),$(findstring Python 3.,$(shell $(PYTHON) --version))))
+  $(error Python 3 not installed for testing)
+endif

Makefile

@@ -8,7 +8,9 @@ endif
 endif
 
 BPAN := .bpan
+VENV := .venv
 
+export PATH := .venv/bin:$(PATH)
 
 #------------------------------------------------------------------------------
 # User targets
@@ -23,9 +25,8 @@ test-bash: $(BPAN)
 	$(call run-with,prove,$@,\
 	prove -r $(if $v,-v )$(test))
 
-test-python:
-	$(call run-with,py.test,$@,\
-	py.test tests)
+test-python: $(VENV)
+	py.test tests
 
 test-online:
 	dry_run=1 bash -x ./openqa-label-known-issues-multi < ./tests/incompletes
@@ -48,7 +49,7 @@ update-deps:
 
 clean:
 	$(RM) job_post_response
-	$(RM) -r $(BPAN)
+	$(RM) -r $(BPAN) $(VENV)
 	$(RM) -r .pytest_cache/
 	find . -name __pycache__ | xargs -r $(RM) -r
 
@@ -57,3 +58,7 @@ clean:
 #------------------------------------------------------------------------------
 $(BPAN):
 	git clone https://github.com/bpan-org/bpan.git --depth 1 $@
+
+$(VENV):
+	$(PYTHON) -m venv $@
+	pip install pytest requests