Add a run-with Makefile function

The run-with function checks to make sure that the runner command is
installed before running the test.

If not installed it issues a warning message.
It used to just fail, which causes all of `make test` to fail.

Also before there where lines to check if shellcheck and yamllint were
installed. They printed a msg but did not stop the commands from
attempting to run only to obviously fail for not being installed.

There was no previous check for py.test which was always failing for me
since I didn't have it installed.

Now when something isn't installed that test is just skipped with an
explanation message.

.setup.mk

@@ -3,6 +3,12 @@ SHELL := bash
 .DELETE_ON_ERROR:
 .SECONDEXPANSION:
 
+define run-with
+$(if $(shell command -v $1), \
+$3, \
+$(warning WARNING: Can't 'make $2'. No '$1' command found.))
+endef
+
 ifeq (,$(shell git diff --stat))
 GIT_STATUS_IS_CLEAN := 1
 endif

Makefile

@@ -20,10 +20,12 @@ test: checkstyle test-unit
 test-unit: test-bash test-python
 
 test-bash: $(BPAN)
-	prove -r $(if $v,-v )$(test)
+	$(call run-with,prove,$@,\
+	prove -r $(if $v,-v )$(test))
 
 test-python:
-	py.test tests
+	$(call run-with,py.test,$@,\
+	py.test tests)
 
 test-online:
 	cat ./tests/incompletes | env dry_run=1 bash -ex ./openqa-label-known-issues-multi
@@ -34,12 +36,12 @@ test-online:
 checkstyle: test-shellcheck test-yaml
 
 test-shellcheck:
-	@which shellcheck >/dev/null 2>&1 || echo "Command 'shellcheck' not found, can not execute shell script checks"
-	shellcheck -x $$(file --mime-type * | sed -n 's/^\(.*\):.*text\/x-shellscript.*$$/\1/p')
+	$(call run-with,shellcheck,$@,\
+	shellcheck -x $$(file --mime-type * | sed -n 's/^\(.*\):.*text\/x-shellscript.*$$/\1/p'))
 
 test-yaml:
-	@which yamllint >/dev/null 2>&1 || echo "Command 'yamllint' not found, can not execute YAML syntax checks"
-	yamllint --strict $$(git ls-files "*.yml" "*.yaml" ":!external/")
+	$(call run-with,yamllint,$@,\
+	yamllint --strict $$(git ls-files "*.yml" "*.yaml" ":!external/"))
 
 update-deps:
 	tools/update-deps --specfile dist/rpm/os-autoinst-scripts-deps.spec