diff --git a/.travis.yml b/.travis.yml
index 1e27140..7f96f8a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -7,7 +7,7 @@ python:
 
 install:
   - if [ "${TRAVIS_BRANCH}" = "master" -a "${TRAVIS_PULL_REQUEST}" = "false" ]; then rm -rf env; fi
-  - touch requirements.txt
+  - touch requirements.txt requirements_tests.txt
   - make env
 
 cache:
diff --git a/Makefile b/Makefile
index 4fea7f3..b0a4d56 100644
--- a/Makefile
+++ b/Makefile
@@ -6,7 +6,7 @@ bin_dir := $(shell $(python) -c 'import sys; bin = "Scripts" if sys.platform ==
 env_bin := env/$(bin_dir)
 venv := "./vendor/virtualenv-12.0.7.py"
 
-env:
+env: requirements.txt requirements_tests.txt
 	$(python)  $(venv)\
 				--prompt="[inside.gratipay.com] " \
 				--never-download \