   end
 
   test "app revision from application env" do
-    System.delete_env("APP_REVISION")
     Application.put_env(:appsignal, :config,
       push_api_key: "-test",
       revision: "b5f2b9")


  alias Appsignal.Config

  test "unconfigured" do
    System.put_env("APPSIGNAL_PUSH_API_KEY", "")
    Application.delete_env(:appsignal, :config)
    assert {:error, :invalid_config} = Config.initialize()
  end


  end

  test "app config from application env gets put in system env" do

    Application.put_env(:appsignal, :config,
      active: true,
