Added (eventually superfluous) makefile to test_build

tests/test_build/Makefile

+
+.PHONY: default
+default: test
+
+.PHONY: test
+test: check_env 
+	@pytest . -v
+
+.PHONY: check_env
+check_env: guard-EPICS_BASE guard-E3_REQUIRE_VERSION
+	@#$(or $(wildcard ${EPICS_BASE}/require/${E3_REQUIRE_VERSION}/bin/setE3Env.bash), $(error setE3Env.bash not found. Please check your version of base and require.))
+
+guard-%:
+	@#$(or ${$*}, $(error $* is not set))
+