diff --git a/tests/pipdeptree_tests.py b/tests/pipdeptree_tests.py
index 4e4f5db..29b9a65 100644
--- a/tests/pipdeptree_tests.py
+++ b/tests/pipdeptree_tests.py
@@ -3,7 +3,7 @@ import pickle
 from pipdeptree import req_version, non_top_pkg_name, render_tree
 
 
-with open('tests/pkgs.p') as f:
+with open('tests/pkgs.pickle') as f:
     pkgs = pickle.load(f)
 
 
diff --git a/tests/pkgs.p b/tests/pkgs.pickle
similarity index 100%
rename from tests/pkgs.p
rename to tests/pkgs.pickle