test(ui): cover composer handoff preview spacing

ui/src/components/IssueChatComposerHandoffPreview.test.ts

@@ -0,0 +1,32 @@
+import { describe, expect, it } from "vitest";
+import { computeComposerHandoffPreview } from "../lib/interrupt-handoff";
+import { shouldRenderComposerHandoffPreview } from "./IssueChatThread";
+
+describe("shouldRenderComposerHandoffPreview", () => {
+  it("skips the spacer wrapper when the preview is empty", () => {
+    const preview = computeComposerHandoffPreview({
+      reassignTarget: "agent:agent-claude",
+      currentAssigneeValue: "agent:agent-claude",
+      hasActiveRun: true,
+      bodyHasAgentMention: false,
+      plainNameCandidate: null,
+    });
+
+    expect(preview.kind).toBe("none");
+    expect(shouldRenderComposerHandoffPreview("Wake Claude", preview)).toBe(false);
+  });
+
+  it("renders the spacer wrapper only when body text and a visible preview are present", () => {
+    const preview = computeComposerHandoffPreview({
+      reassignTarget: "agent:agent-qa",
+      currentAssigneeValue: "agent:agent-claude",
+      hasActiveRun: true,
+      bodyHasAgentMention: false,
+      plainNameCandidate: null,
+    });
+
+    expect(preview.kind).not.toBe("none");
+    expect(shouldRenderComposerHandoffPreview("Wake QA", preview)).toBe(true);
+    expect(shouldRenderComposerHandoffPreview("   ", preview)).toBe(false);
+  });
+});

ui/src/components/IssueChatThread.tsx

@@ -120,6 +120,7 @@ import {
   computeComposerHandoffPreview,
   extractAgentMentionIds,
   findPlainAgentNameCandidate,
+  type ComposerHandoffPreview,
   type HandoffAgentMention,
 } from "../lib/interrupt-handoff";
 import { restoreSubmittedCommentDraft } from "../lib/comment-submit-draft";
@@ -316,6 +317,10 @@ interface CommentReassignment {
   assigneeUserId: string | null;
 }
 
+export function shouldRenderComposerHandoffPreview(body: string, preview: ComposerHandoffPreview): boolean {
+  return Boolean(body.trim()) && preview.kind !== "none";
+}
+
 export interface IssueChatComposerHandle {
   focus: () => void;
   restoreDraft: (submittedBody: string) => void;
@@ -3840,7 +3845,7 @@ const IssueChatComposer = forwardRef<IssueChatComposerHandle, IssueChatComposerP
         </div>
       ) : null}
 
-      {body.trim() && handoffPreview.kind !== "none" ? (
+      {shouldRenderComposerHandoffPreview(body, handoffPreview) ? (
         <div className="my-2">
           <ComposerHandoffPreviewRow preview={handoffPreview} resolvers={handoffResolvers} />
         </div>