mix phx.new labelmaker --no-ecto --no-mailer

test/labelmaker_web/controllers/error_html_test.exs

@@ -0,0 +1,14 @@
+defmodule LabelmakerWeb.ErrorHTMLTest do
+  use LabelmakerWeb.ConnCase, async: true
+
+  # Bring render_to_string/4 for testing custom views
+  import Phoenix.Template
+
+  test "renders 404.html" do
+    assert render_to_string(LabelmakerWeb.ErrorHTML, "404", "html", []) == "Not Found"
+  end
+
+  test "renders 500.html" do
+    assert render_to_string(LabelmakerWeb.ErrorHTML, "500", "html", []) == "Internal Server Error"
+  end
+end