feat: first take at M4

crates/bds-core/tests/m4_render.rs

@@ -0,0 +1,174 @@
+use std::collections::HashMap;
+
+use bds_core::model::{Post, PostStatus, Tag, Template, TemplateKind, TemplateStatus};
+use bds_core::render::{
+    RenderCategorySettings, RenderTemplateLookup, TemplateLookupError,
+    render_markdown_to_html, resolve_post_template,
+};
+
+fn make_post() -> Post {
+    Post {
+        id: "post-1".into(),
+        project_id: "project-1".into(),
+        title: "Post".into(),
+        slug: "post".into(),
+        excerpt: None,
+        content: Some("# Hello".into()),
+        status: PostStatus::Published,
+        author: None,
+        language: Some("en".into()),
+        do_not_translate: false,
+        template_slug: None,
+        file_path: "posts/2026/04/10/post.md".into(),
+        checksum: None,
+        tags: vec![],
+        categories: vec![],
+        published_title: None,
+        published_content: None,
+        published_tags: None,
+        published_categories: None,
+        published_excerpt: None,
+        created_at: 1,
+        updated_at: 1,
+        published_at: Some(1),
+    }
+}
+
+fn make_template(slug: &str) -> Template {
+    Template {
+        id: format!("template-{slug}"),
+        project_id: "project-1".into(),
+        slug: slug.into(),
+        title: slug.into(),
+        kind: TemplateKind::Post,
+        enabled: true,
+        version: 1,
+        file_path: format!("templates/{slug}.liquid"),
+        status: TemplateStatus::Published,
+        content: Some(format!("template:{slug}")),
+        created_at: 1,
+        updated_at: 1,
+    }
+}
+
+fn make_tag(name: &str, post_template_slug: Option<&str>) -> Tag {
+    Tag {
+        id: format!("tag-{name}"),
+        project_id: "project-1".into(),
+        name: name.into(),
+        color: None,
+        post_template_slug: post_template_slug.map(ToOwned::to_owned),
+        created_at: 1,
+        updated_at: 1,
+    }
+}
+
+#[test]
+fn template_lookup_prefers_post_specific_template() {
+    let mut post = make_post();
+    post.template_slug = Some("custom".into());
+    post.tags = vec!["rust".into()];
+    post.categories = vec!["article".into()];
+
+    let templates = vec![make_template("post"), make_template("tag-template"), make_template("custom")];
+    let tags = vec![make_tag("rust", Some("tag-template"))];
+    let mut categories = HashMap::new();
+    categories.insert(
+        "article".into(),
+        RenderCategorySettings {
+            post_template_slug: Some("category-template".into()),
+        },
+    );
+
+    let resolved = resolve_post_template(RenderTemplateLookup {
+        post: &post,
+        templates: &templates,
+        tags: &tags,
+        category_settings: &categories,
+    })
+    .unwrap();
+
+    assert_eq!(resolved.slug, "custom");
+}
+
+#[test]
+fn template_lookup_falls_back_to_tag_then_category_then_default() {
+    let mut post = make_post();
+    post.tags = vec!["rust".into()];
+    post.categories = vec!["article".into()];
+
+    let templates = vec![
+        make_template("post"),
+        make_template("tag-template"),
+        make_template("category-template"),
+    ];
+    let tags = vec![make_tag("rust", Some("tag-template"))];
+    let mut categories = HashMap::new();
+    categories.insert(
+        "article".into(),
+        RenderCategorySettings {
+            post_template_slug: Some("category-template".into()),
+        },
+    );
+
+    let resolved = resolve_post_template(RenderTemplateLookup {
+        post: &post,
+        templates: &templates,
+        tags: &tags,
+        category_settings: &categories,
+    })
+    .unwrap();
+    assert_eq!(resolved.slug, "tag-template");
+
+    let category_post = Post {
+        tags: vec![],
+        ..post.clone()
+    };
+    let resolved = resolve_post_template(RenderTemplateLookup {
+        post: &category_post,
+        templates: &templates,
+        tags: &tags,
+        category_settings: &categories,
+    })
+    .unwrap();
+    assert_eq!(resolved.slug, "category-template");
+
+    let default_post = Post {
+        tags: vec![],
+        categories: vec![],
+        ..post
+    };
+    let empty_categories = HashMap::new();
+    let resolved = resolve_post_template(RenderTemplateLookup {
+        post: &default_post,
+        templates: &templates,
+        tags: &tags,
+        category_settings: &empty_categories,
+    })
+    .unwrap();
+    assert_eq!(resolved.slug, "post");
+}
+
+#[test]
+fn template_lookup_errors_when_explicit_template_missing() {
+    let mut post = make_post();
+    post.template_slug = Some("missing".into());
+    let templates = vec![make_template("post")];
+
+    let err = resolve_post_template(RenderTemplateLookup {
+        post: &post,
+        templates: &templates,
+        tags: &[],
+        category_settings: &HashMap::new(),
+    })
+    .unwrap_err();
+
+    assert_eq!(err, TemplateLookupError::MissingExplicitTemplate("missing".into()));
+}
+
+#[test]
+fn markdown_render_produces_html() {
+    let html = render_markdown_to_html("# Hello\n\nA paragraph with **bold** text.");
+    assert!(html.contains("<h1>Hello</h1>"));
+    assert!(html.contains("<strong>bold</strong>"));
+}