diff --git a/test/Project.toml b/test/Project.toml
index c3a69f9a..08bb5032 100644
--- a/test/Project.toml
+++ b/test/Project.toml
@@ -12,3 +12,6 @@ Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 
 [sources]
 MLDatasets = {path = ".."}
+
+[compat]
+Pickle = "0.3.7"