 
   describe "changeset/2" do
     test "returns invalid changeset when attrs are missing" do
-      changeset = Address.changeset(%Address{}, %{})
+      missing_params = %{}
+
+      changeset = Address.changeset(%Address{}, missing_params)
 
       refute changeset.valid?
       assert %{address: ["can't be blank"]} = errors_on(changeset)

      refute Map.has_key?(changeset.changes, :tx_count)
    end
  end
end


    test "returns invalid changeset when attrs are invalid" do
      cast_fields = [:address, :balance, :time]
      invalid_attrs = cast_fields |> Enum.map(fn field -> {field, :invalid} end) |> Map.new()
      changeset = Address.changeset(%Address{}, invalid_attrs)

      refute changeset.valid?

