story-kit: merge 215_bug_cancel_button_still_discards_queued_messages_197_regression

frontend/src/components/ChatInput.test.tsx

@@ -1,5 +1,7 @@
 import { act, fireEvent, render, screen } from "@testing-library/react";
+import * as React from "react";
 import { describe, expect, it, vi } from "vitest";
+import type { ChatInputHandle } from "./ChatInput";
 import { ChatInput } from "./ChatInput";
 
 describe("ChatInput component (Story 178 AC1)", () => {
@@ -200,3 +202,78 @@ describe("ChatInput component (Story 178 AC1)", () => {
 		expect(onRemove).toHaveBeenCalledWith("q1");
 	});
 });
+
+describe("ChatInput appendToInput (Bug 215 regression)", () => {
+	it("appendToInput sets text into an empty input", async () => {
+		const ref = React.createRef<ChatInputHandle>();
+
+		render(
+			<ChatInput
+				ref={ref}
+				loading={false}
+				queuedMessages={[]}
+				onSubmit={vi.fn()}
+				onCancel={vi.fn()}
+				onRemoveQueuedMessage={vi.fn()}
+			/>,
+		);
+
+		await act(async () => {
+			ref.current?.appendToInput("queued message");
+		});
+
+		const textarea = screen.getByPlaceholderText("Send a message...");
+		expect((textarea as HTMLTextAreaElement).value).toBe("queued message");
+	});
+
+	it("appendToInput appends to existing input content with a newline separator", async () => {
+		const ref = React.createRef<ChatInputHandle>();
+
+		render(
+			<ChatInput
+				ref={ref}
+				loading={false}
+				queuedMessages={[]}
+				onSubmit={vi.fn()}
+				onCancel={vi.fn()}
+				onRemoveQueuedMessage={vi.fn()}
+			/>,
+		);
+
+		const textarea = screen.getByPlaceholderText("Send a message...");
+
+		await act(async () => {
+			fireEvent.change(textarea, { target: { value: "existing text" } });
+		});
+
+		await act(async () => {
+			ref.current?.appendToInput("appended text");
+		});
+
+		expect((textarea as HTMLTextAreaElement).value).toBe(
+			"existing text\nappended text",
+		);
+	});
+
+	it("multiple queued messages joined with newlines are appended on cancel", async () => {
+		const ref = React.createRef<ChatInputHandle>();
+
+		render(
+			<ChatInput
+				ref={ref}
+				loading={false}
+				queuedMessages={[]}
+				onSubmit={vi.fn()}
+				onCancel={vi.fn()}
+				onRemoveQueuedMessage={vi.fn()}
+			/>,
+		);
+
+		await act(async () => {
+			ref.current?.appendToInput("msg one\nmsg two");
+		});
+
+		const textarea = screen.getByPlaceholderText("Send a message...");
+		expect((textarea as HTMLTextAreaElement).value).toBe("msg one\nmsg two");
+	});
+});