Add make test-reqs and separate requirements file

Make local test setup easier

.travis.yml

@@ -5,6 +5,6 @@ sudo: required
 services:
     - docker
 install:
-    - pip install docker pytest requests
+    - make test-env
 script:
     - make build-test-all

Makefile

@@ -54,6 +54,9 @@ dev/%: PORT?=8888
 dev/%: ## run a foreground container for a stack
 	docker run -it --rm -p $(PORT):8888 $(DARGS) $(OWNER)/$(notdir $@) $(ARGS)
 
+test-reqs: # install libraries required to run the integration tests
+	pip install -r requirements-test.txt
+
 test/%:
 	@TEST_IMAGE="$(OWNER)/$(notdir $@)" pytest test
 

requirements-test.txt

+docker
+pytest
+requests
\ No newline at end of file