test(lsp): cover documented completions

Add protocol and helper coverage for documented hemplate completion items, including data-hemx-root.

req: diagnostics/006

hemx-lsp/src/main.rs

@@ -394,6 +394,11 @@ fn hemplate_completion_items(
             "{+= trusted_html =+}",
             "Trusted/rendered HTML expression; prefer escaped `{+ expr +}` for user content.",
         ),
+        completion_item(
+            "data-hemx-root",
+            "data-hemx-root=\"app\"",
+            "Generated hemx root for delegated runtime behavior.",
+        ),
         completion_item(
             "data-hemx-slot",
             "data-hemx-slot=\"content\"",
@@ -746,6 +751,81 @@ mod tests {
         assert!(!outside_hover.to_string().contains("exercise.name: String"));
     }
 
+    #[test]
+    fn completion_items_cover_documented_hemplate_surface() {
+        // req: diagnostics/006
+        let text = r#"<main data-hemx-root="app"><template h-for="item in &self.items" h-key="item.id"><p +class="self.class_name">{+ self.title +}{+= trusted =+}</p></template></main>"#;
+        let items = hemplate_completion_items("file:///tmp/app.heml", text, Some((0, 6)));
+        let labels = items
+            .iter()
+            .filter_map(|item| item["label"].as_str())
+            .collect::<std::collections::BTreeSet<_>>();
+        for label in [
+            "h-for",
+            "h-key",
+            "h-if",
+            "h-match",
+            "h-case",
+            "+attr",
+            "{+ expr +}",
+            "{+= expr =+}",
+            "data-hemx-root",
+            "data-hemx-slot",
+            "data-hemx-form",
+            "data-hemx-handle",
+        ] {
+            assert!(labels.contains(label), "missing completion item `{label}`");
+        }
+        assert!(items.iter().all(|item| item["documentation"]["value"]
+            .as_str()
+            .unwrap_or_default()
+            .contains("docs/hemplate-syntax.md")));
+    }
+
+    #[test]
+    fn lsp_completion_returns_documented_items() {
+        // req: diagnostics/006
+        let text = r#"<main data-hemx-root="todos"><div data-hemx-slot="content">{+ self.title +}</div></main>"#;
+        let uri = "file:///tmp/completion.heml";
+        let input = [
+            lsp_message(serde_json::json!({"jsonrpc": "2.0", "id": 1, "method": "initialize", "params": {}})),
+            lsp_message(serde_json::json!({
+                "jsonrpc": "2.0",
+                "method": "textDocument/didOpen",
+                "params": {"textDocument": {"uri": uri, "languageId": "heml", "version": 1, "text": text}}
+            })),
+            lsp_message(serde_json::json!({
+                "jsonrpc": "2.0",
+                "id": 2,
+                "method": "textDocument/completion",
+                "params": {"textDocument": {"uri": uri}, "position": {"line": 0, "character": 6}}
+            })),
+            lsp_message(serde_json::json!({"jsonrpc": "2.0", "method": "exit"})),
+        ]
+        .join("");
+        let mut reader = std::io::BufReader::new(input.as_bytes());
+        let mut output = Vec::new();
+
+        serve_lsp(&mut reader, &mut output).expect("serve LSP");
+        let messages = lsp_messages(&output);
+        let completion = messages
+            .iter()
+            .find(|message| message["id"] == 2)
+            .expect("completion response");
+        let completion_items = completion["result"]
+            .as_array()
+            .or_else(|| completion["result"]["items"].as_array())
+            .expect("completion items");
+        let labels = completion_items
+            .iter()
+            .filter_map(|item| item["label"].as_str())
+            .collect::<std::collections::BTreeSet<_>>();
+        assert!(labels.contains("h-if"));
+        assert!(labels.contains("data-hemx-root"));
+        assert!(labels.contains("data-hemx-slot"));
+        assert!(labels.contains("{+ expr +}"));
+    }
+
     #[test]
     fn workout_template_fields_are_available_from_repo_facts() {
         // req: diagnostics/006