test(ui): cover context-heavy comment annotations

Author: benvinegar

src/ui/lib/agentAnnotations.test.ts

@@ -0,0 +1,59 @@
+import { describe, expect, test } from "bun:test";
+import { createTestDiffFile, lines } from "../../../test/helpers/diff-helpers";
+import { buildLiveComment, resolveCommentTarget } from "../../core/liveComments";
+import { getAnnotatedHunkIndices, getSelectedAnnotations } from "./agentAnnotations";
+
+function createContextHeavyHunkFile() {
+  const beforeLines = Array.from({ length: 25 }, (_, i) => `line${i + 1}`);
+  const afterLines = [...beforeLines.slice(0, 12), "INSERTED", ...beforeLines.slice(12)];
+
+  return createTestDiffFile({
+    before: lines(...beforeLines),
+    after: lines(...afterLines),
+    context: 100,
+    id: "file:context-heavy-annotation",
+    path: "src/sparse.ts",
+    previousPath: "src/sparse.ts",
+  });
+}
+
+describe("agent annotations", () => {
+  test("keeps hunk-number comments visible when anchored after leading context", () => {
+    const file = createContextHeavyHunkFile();
+    const hunk = file.metadata.hunks[0]!;
+
+    const target = resolveCommentTarget(file, {
+      filePath: file.path,
+      hunkIndex: 0,
+      summary: "Explain inserted line",
+      rationale: "The daemon resolves hunk-number comments to the first change row.",
+    });
+
+    expect(target).toMatchObject({ hunkIndex: 0, side: "new", line: 13 });
+    expect(hunk.additionLines).toBe(1);
+    expect(hunk.additionCount).toBeGreaterThan(target.line - hunk.additionStart + 1);
+
+    const comment = buildLiveComment(
+      {
+        filePath: file.path,
+        side: target.side,
+        line: target.line,
+        summary: "Explain inserted line",
+        rationale: "The daemon resolves hunk-number comments to the first change row.",
+      },
+      "comment-1",
+      "2026-03-22T00:00:00.000Z",
+      target.hunkIndex,
+    );
+    const annotatedFile = {
+      ...file,
+      agent: {
+        path: file.path,
+        annotations: [comment],
+      },
+    };
+
+    expect([...getAnnotatedHunkIndices(annotatedFile)]).toEqual([0]);
+    expect(getSelectedAnnotations(annotatedFile, hunk)).toEqual([comment]);
+  });
+});