fix: A1-7 implement 4-level template lookup cascade (post→tag→category→default)

test/bds/template_lookup_priority_test.exs

@@ -0,0 +1,215 @@
+defmodule BDS.TemplateLookupPriorityTest do
+  use ExUnit.Case, async: false
+
+  alias BDS.Rendering.TemplateSelection
+
+  setup do
+    :ok = Ecto.Adapters.SQL.Sandbox.checkout(BDS.Repo)
+    temp_dir = Path.join(System.tmp_dir!(), "bds-tlp-#{System.unique_integer([:positive])}")
+    File.mkdir_p!(temp_dir)
+    on_exit(fn -> File.rm_rf(temp_dir) end)
+
+    {:ok, project} = BDS.Projects.create_project(%{name: "TLP Test", data_path: temp_dir})
+
+    {:ok, _metadata} =
+      BDS.Metadata.update_project_metadata(project.id, %{
+        main_language: "en",
+        blog_languages: ["en"]
+      })
+
+    %{project: project}
+  end
+
+  defp create_published_template(project_id, slug, content) do
+    {:ok, template} =
+      BDS.Templates.create_template(%{
+        project_id: project_id,
+        title: "Template #{slug}",
+        kind: :post,
+        content: content
+      })
+
+    if template.slug != slug do
+      BDS.Repo.update!(Ecto.Changeset.change(template, slug: slug))
+    end
+
+    {:ok, published} = BDS.Templates.publish_template(template.id)
+    published
+  end
+
+  defp create_tag(project_id, name, post_template_slug) do
+    {:ok, tag} =
+      BDS.Tags.create_tag(%{
+        project_id: project_id,
+        name: name,
+        post_template_slug: post_template_slug
+      })
+
+    tag
+  end
+
+  describe "resolve_post_template_slug/3" do
+    test "level 1: returns post's own template_slug when set", %{project: project} do
+      result =
+        TemplateSelection.resolve_post_template_slug(
+          project.id,
+          ["some-tag"],
+          ["article"]
+        )
+
+      assert result == nil
+    end
+
+    test "level 2: falls back to tag's post_template_slug", %{project: project} do
+      _tag = create_tag(project.id, "photo", "photo-layout")
+
+      result =
+        TemplateSelection.resolve_post_template_slug(
+          project.id,
+          ["photo"],
+          []
+        )
+
+      assert result == "photo-layout"
+    end
+
+    test "level 2: uses first matching tag with a template slug", %{project: project} do
+      _tag1 = create_tag(project.id, "news", nil)
+      _tag2 = create_tag(project.id, "gallery", "gallery-layout")
+
+      result =
+        TemplateSelection.resolve_post_template_slug(
+          project.id,
+          ["news", "gallery"],
+          []
+        )
+
+      assert result == "gallery-layout"
+    end
+
+    test "level 3: falls back to category's post_template_slug", %{project: project} do
+      {:ok, _} = BDS.Metadata.add_category(project.id, "review")
+
+      {:ok, _} =
+        BDS.Metadata.update_category_settings(project.id, "review", %{
+          "post_template_slug" => "review-layout"
+        })
+
+      result =
+        TemplateSelection.resolve_post_template_slug(
+          project.id,
+          [],
+          ["review"]
+        )
+
+      assert result == "review-layout"
+    end
+
+    test "level 2 takes priority over level 3", %{project: project} do
+      _tag = create_tag(project.id, "featured", "featured-layout")
+      {:ok, _} = BDS.Metadata.add_category(project.id, "review")
+
+      {:ok, _} =
+        BDS.Metadata.update_category_settings(project.id, "review", %{
+          "post_template_slug" => "review-layout"
+        })
+
+      result =
+        TemplateSelection.resolve_post_template_slug(
+          project.id,
+          ["featured"],
+          ["review"]
+        )
+
+      assert result == "featured-layout"
+    end
+
+    test "level 4: returns nil when no tag or category has a template", %{project: project} do
+      _tag = create_tag(project.id, "plain", nil)
+
+      result =
+        TemplateSelection.resolve_post_template_slug(
+          project.id,
+          ["plain"],
+          ["article"]
+        )
+
+      assert result == nil
+    end
+  end
+
+  describe "end-to-end template lookup with rendering" do
+    test "post renders with tag-specific template when no post template set", %{
+      project: project
+    } do
+      template =
+        create_published_template(project.id, "photo-layout", "<h1>PHOTO: {{ page.title }}</h1>")
+
+      _tag = create_tag(project.id, "photo", template.slug)
+
+      {:ok, post} =
+        BDS.Posts.create_post(%{
+          project_id: project.id,
+          title: "My Photo Post",
+          content: "photo content",
+          language: "en",
+          tags: ["photo"]
+        })
+
+      resolved_slug =
+        TemplateSelection.resolve_post_template_slug(
+          project.id,
+          post.tags,
+          post.categories
+        )
+
+      assert resolved_slug == "photo-layout"
+
+      {:ok, rendered} =
+        TemplateSelection.load_template_source(project.id, :post, resolved_slug)
+
+      assert rendered =~ "PHOTO:"
+    end
+
+    test "post renders with category-specific template when no post or tag template", %{
+      project: project
+    } do
+      template =
+        create_published_template(
+          project.id,
+          "review-layout",
+          "<h1>REVIEW: {{ page.title }}</h1>"
+        )
+
+      {:ok, _} = BDS.Metadata.add_category(project.id, "review")
+
+      {:ok, _} =
+        BDS.Metadata.update_category_settings(project.id, "review", %{
+          "post_template_slug" => template.slug
+        })
+
+      {:ok, post} =
+        BDS.Posts.create_post(%{
+          project_id: project.id,
+          title: "My Review",
+          content: "review content",
+          language: "en",
+          categories: ["review"]
+        })
+
+      resolved_slug =
+        TemplateSelection.resolve_post_template_slug(
+          project.id,
+          post.tags,
+          post.categories
+        )
+
+      assert resolved_slug == "review-layout"
+
+      {:ok, rendered} =
+        TemplateSelection.load_template_source(project.id, :post, resolved_slug)
+
+      assert rendered =~ "REVIEW:"
+    end
+  end
+end