test(frontend): add comprehensive tests for components, hooks, and state

Add 84 new tests covering Jotai atoms (play/watch state transitions,
game timing, score management), utility functions (calcCodeSize,
checkGameResultKind), UI components (SubmitStatusLabel, LeftTime,
SubmitButton, InputText, BorderedContainerWithCaption,
FoldableBorderedContainerWithCaption, UserIcon, PlayerNameAndIcon),
and the usePageTitle hook.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

1 files changed, 47 insertions, 0 deletions

diff --git a/frontend/app/components/Gaming/LeftTime.test.tsx b/frontend/app/components/Gaming/LeftTime.test.tsx
new file mode 100644
index 0000000..742d8eb
--- /dev/null
+++ b/frontend/app/components/Gaming/LeftTime.test.tsx
@@ -0,0 +1,47 @@
+/**
+ * @vitest-environment jsdom
+ */
+import { cleanup, render, screen } from "@testing-library/react";
+import { afterEach, describe, expect, test } from "vitest";
+import LeftTime from "./LeftTime";
+
+afterEach(() => {
+	cleanup();
+});
+
+describe("LeftTime", () => {
+	test("renders MM:SS format for short durations", () => {
+		render(<LeftTime sec={65} />);
+		expect(screen.getByText("01:05")).toBeDefined();
+	});
+
+	test("renders 00:00 for zero seconds", () => {
+		render(<LeftTime sec={0} />);
+		expect(screen.getByText("00:00")).toBeDefined();
+	});
+
+	test("renders MM:SS with leading zeros", () => {
+		render(<LeftTime sec={5} />);
+		expect(screen.getByText("00:05")).toBeDefined();
+	});
+
+	test("renders 59:59 for max MM:SS range", () => {
+		render(<LeftTime sec={3599} />);
+		expect(screen.getByText("59:59")).toBeDefined();
+	});
+
+	test("renders long format with hours", () => {
+		render(<LeftTime sec={3661} />);
+		expect(screen.getByText("1h 1m 1s")).toBeDefined();
+	});
+
+	test("renders long format with days", () => {
+		render(<LeftTime sec={90061} />);
+		expect(screen.getByText("1d 1h 1m 1s")).toBeDefined();
+	});
+
+	test("renders long format omitting zero day and minute", () => {
+		render(<LeftTime sec={3605} />);
+		expect(screen.getByText("1h 5s")).toBeDefined();
+	});
+});