test(lsp): cover documented hover facts

Make hover token-position aware and add protocol/helper coverage for documented hemplate hover facts.

req: diagnostics/007

req: diagnostics/008

hemx-lsp/src/main.rs

@@ -510,25 +510,29 @@ fn hemplate_hover(uri: &str, text: &str, position: Option<(usize, usize)>) -> se
     let line = position
         .and_then(|(line, _)| text.lines().nth(line))
         .unwrap_or_default();
-    let value = if line.contains("data-hemx-slot") {
+    let character = position.map(|(_, character)| character).unwrap_or_default();
+    let at = |token: &str| token_at(line, character, token);
+    let value = if at("data-hemx-root") {
+        Some("`data-hemx-root` declares the root where the hemx runtime scopes delegated handlers and generated resources.")
+    } else if at("data-hemx-slot") {
         Some("`data-hemx-slot` declares a generated partial target. Inside `h-for`, add template `h-key`; compiler diagnostics come from `hemx-build`.")
-    } else if line.contains("data-hemx-form") {
+    } else if at("data-hemx-form") {
         Some("`data-hemx-form` declares a generated form target wired through hemx build output.")
-    } else if line.contains("data-hemx-handle") {
+    } else if at("data-hemx-handle") {
         Some("`data-hemx-handle` declares a generated handle target wired through hemx build output.")
-    } else if line.contains("h-key") {
+    } else if at("h-key") {
         Some("`h-key` is the stable template key used by generated targets inside `h-for` loops.")
-    } else if line.contains("h-for") {
+    } else if at("h-for") {
         Some("`h-for` repeats children from a Rust-shaped iterator expression; generated targets inside the loop require `h-key`.")
-    } else if line.contains("h-if") {
+    } else if at("h-if") {
         Some("`h-if` renders an element when a Rust-shaped condition is true.")
-    } else if line.contains("h-match") || line.contains("h-case") {
+    } else if at("h-match") || at("h-case") {
         Some("`h-match`/`h-case` use Rust-shaped pattern arms; `h-case=\"_\"` is the default arm.")
-    } else if line.contains("{+=") {
+    } else if at("{+=") {
         Some("`{+= expr =+}` inserts trusted/rendered HTML. Prefer escaped `{+ expr +}` for user content.")
-    } else if line.contains("{+") {
+    } else if at("{+") {
         Some("`{+ expr +}` inserts escaped text.")
-    } else if line.contains('+') {
+    } else if at("+") {
         Some("`+attr=\"expr\"` evaluates a dynamic HTML attribute expression.")
     } else {
         None
@@ -541,6 +545,11 @@ fn hemplate_hover(uri: &str, text: &str, position: Option<(usize, usize)>) -> se
     }
 }
 
+fn token_at(line: &str, character: usize, token: &str) -> bool {
+    line.match_indices(token)
+        .any(|(start, matched)| character >= start && character < start + matched.len())
+}
+
 fn hover_markdown(value: &str) -> serde_json::Value {
     serde_json::json!({
         "contents": {
@@ -826,6 +835,74 @@ mod tests {
         assert!(labels.contains("{+ expr +}"));
     }
 
+    #[test]
+    fn hover_items_cover_documented_hemplate_surface() {
+        // req: diagnostics/007 req: diagnostics/008
+        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 cases = [
+            ("data-hemx-root", "runtime scopes delegated handlers"),
+            ("h-for", "repeats children"),
+            ("h-key", "stable template key"),
+            ("+class", "dynamic HTML attribute"),
+            ("{+ self.title +}", "escaped text"),
+            ("{+= trusted =+}", "trusted/rendered HTML"),
+        ];
+        for (needle, expected) in cases {
+            let character = text.find(needle).expect("fixture needle");
+            let hover = hemplate_hover("file:///tmp/hover.heml", text, Some((0, character)));
+            let value = hover_markdown_value(&hover);
+            assert!(
+                value.contains(expected),
+                "hover for `{needle}` should mention `{expected}`, got {value:?}"
+            );
+            assert!(
+                value.contains("docs/hemplate-syntax.md"),
+                "hover for `{needle}` should cite syntax docs, got {value:?}"
+            );
+        }
+        assert_eq!(
+            hemplate_hover("file:///tmp/hover.heml", text, Some((0, 0))),
+            serde_json::Value::Null,
+            "ordinary HTML text is left to normal editor tooling"
+        );
+    }
+
+    #[test]
+    fn lsp_hover_returns_documented_markdown() {
+        // req: diagnostics/007 req: diagnostics/008
+        let text = r#"<main data-hemx-root="app"><template h-for="item in &self.items" h-key="item.id"><p>{+ item.title +}</p></template></main>"#;
+        let uri = "file:///tmp/hover.heml";
+        let character = text.find("h-key").expect("h-key position");
+        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/hover",
+                "params": {"textDocument": {"uri": uri}, "position": {"line": 0, "character": character}}
+            })),
+            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 hover = messages
+            .iter()
+            .find(|message| message["id"] == 2)
+            .expect("hover response");
+        let value = hover_markdown_value(&hover["result"]);
+        assert!(value.contains("stable template key"));
+        assert!(value.contains("docs/hemplate-syntax.md"));
+    }
+
     #[test]
     fn workout_template_fields_are_available_from_repo_facts() {
         // req: diagnostics/006
@@ -1034,6 +1111,13 @@ mod tests {
         assert!(output.contains("docs/hemplate-syntax.md"));
     }
 
+    fn hover_markdown_value(hover: &serde_json::Value) -> String {
+        hover["contents"]["value"]
+            .as_str()
+            .unwrap_or_default()
+            .to_string()
+    }
+
     fn lsp_messages(output: &[u8]) -> Vec<serde_json::Value> {
         let mut bytes = output;
         let mut messages = Vec::new();