After 'mix phx.new generic_rest_server --binary-id --no-install'

test/generic_rest_server_web/controllers/page_controller_test.exs

@@ -0,0 +1,8 @@
+defmodule GenericRestServerWeb.PageControllerTest do
+  use GenericRestServerWeb.ConnCase
+
+  test "GET /", %{conn: conn} do
+    conn = get(conn, ~p"/")
+    assert html_response(conn, 200) =~ "Peace of mind from prototype to production"
+  end
+end