test: improve sitemap controller test coverage

Assign response body once to fix the double call, rename the test,
and assert all 6 public URLs plus the exact <loc> count.

test/towerops_web/controllers/sitemap_controller_test.exs

@@ -2,17 +2,20 @@ defmodule ToweropsWeb.SitemapControllerTest do
   use ToweropsWeb.ConnCase, async: true
 
   describe "GET /sitemap.xml" do
-    test "returns valid XML with public pages", %{conn: conn} do
+    test "returns valid XML with all public pages", %{conn: conn} do
       conn = get(conn, "/sitemap.xml")
 
-      assert response(conn, 200)
-      assert get_resp_header(conn, "content-type") == ["text/xml; charset=utf-8"]
       body = response(conn, 200)
+      assert get_resp_header(conn, "content-type") == ["text/xml; charset=utf-8"]
       assert body =~ ~r/<\?xml/
       assert body =~ "<urlset"
-      assert body =~ "<loc>"
-      assert body =~ "/privacy"
-      assert body =~ "/terms"
+      assert body =~ ~r|<loc>http[^<]+/</loc>|
+      assert body =~ "/privacy</loc>"
+      assert body =~ "/terms</loc>"
+      assert body =~ "/docs/api</loc>"
+      assert body =~ "/docs/graphql</loc>"
+      assert body =~ "/help</loc>"
+      assert length(Regex.scan(~r/<loc>/, body)) == 6
     end
   end
 end