diff --git a/requirements.test.txt b/requirements.test.txt
index 2a937fc..02991bd 100644
--- a/requirements.test.txt
+++ b/requirements.test.txt
@@ -6,3 +6,4 @@ descartes>=1.0
 mock>=1.0.1  # technically not need for python >= 3.3
 pytest-cov
 coveralls
+rtree>=0.8