diff --git a/setup.py b/setup.py
index 75d92f79..960f83bb 100644
--- a/setup.py
+++ b/setup.py
@@ -49,6 +49,7 @@ tests_require = [
     "pytest-benchmark",
     "pytest-cov",
     "pytest-mock",
+    "fastdiff==0.2.0",
     "snapshottest",
     "coveralls",
     "promise",