diff --git a/mix.exs b/mix.exs
index fd8b6b1..4095c68 100644
--- a/mix.exs
+++ b/mix.exs
@@ -41,6 +41,7 @@ defmodule GraphQLWSClient.MixProject do
   # Run "mix help deps" to learn about dependencies.
   defp deps do
     [
+      {:castore, "~> 1.0", only: :test, runtime: false},
       {:connection, "~> 1.1"},
       {:credo, "~> 1.7", only: [:dev, :test], runtime: false},
       {:excoveralls, "~> 0.18", only: :test, runtime: false},
diff --git a/mix.lock b/mix.lock
index 52dabb5..b7f964a 100644
--- a/mix.lock
+++ b/mix.lock
@@ -1,5 +1,6 @@
 %{
   "bunt": {:hex, :bunt, "1.0.0", "081c2c665f086849e6d57900292b3a161727ab40431219529f13c4ddcf3e7a44", [:mix], [], "hexpm", "dc5f86aa08a5f6fa6b8096f0735c4e76d54ae5c9fa2c143e5a1fc7c1cd9bb6b5"},
+  "castore": {:hex, :castore, "1.0.6", "ffc42f110ebfdafab0ea159cd43d31365fa0af0ce4a02ecebf1707ae619ee727", [:mix], [], "hexpm", "374c6e7ca752296be3d6780a6d5b922854ffcc74123da90f2f328996b962d33a"},
   "connection": {:hex, :connection, "1.1.0", "ff2a49c4b75b6fb3e674bfc5536451607270aac754ffd1bdfe175abe4a6d7a68", [:mix], [], "hexpm", "722c1eb0a418fbe91ba7bd59a47e28008a189d47e37e0e7bb85585a016b2869c"},
   "cowlib": {:hex, :cowlib, "2.13.0", "db8f7505d8332d98ef50a3ef34b34c1afddec7506e4ee4dd4a3a266285d282ca", [:make, :rebar3], [], "hexpm", "e1e1284dc3fc030a64b1ad0d8382ae7e99da46c3246b815318a4b848873800a4"},
   "credo": {:hex, :credo, "1.7.5", "643213503b1c766ec0496d828c90c424471ea54da77c8a168c725686377b9545", [:mix], [{:bunt, "~> 0.2.1 or ~> 1.0", [hex: :bunt, repo: "hexpm", optional: false]}, {:file_system, "~> 0.2 or ~> 1.0", [hex: :file_system, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "f799e9b5cd1891577d8c773d245668aa74a2fcd15eb277f51a0131690ebfb3fd"},