diff --git a/Cargo.toml b/Cargo.toml
index 3ad9ea6..345e59f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -43,6 +43,7 @@ cookie_store = { version = "0.12.0", optional = true }
 log = "0.4.11"
 
 [dev-dependencies]
+serde = { version = "1", features = ["derive"] }
 env_logger = "0.7.1"
 
 [[example]]