test(export): add failing tests for ExportButton component

8 tests for dropdown toggle, JSON/CSV/Metrics export options. All fail.

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

Author: h4x0r

src/features/observability/ExportButton.tsx

@@ -0,0 +1,9 @@
+// RED STUB
+import React from "react";
+import type { MetricsExport } from "../../lib/export";
+
+interface Props {
+  metrics?: MetricsExport;
+}
+
+export const ExportButton: React.FC<Props> = () => null;

src/features/observability/__tests__/ExportButton.test.tsx

@@ -0,0 +1,75 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import { render, screen, fireEvent } from "@testing-library/react";
+import { ExportButton } from "../ExportButton";
+
+vi.mock("../../../lib/export", () => ({
+  exportTasksAsJson: vi.fn().mockReturnValue('{"tasks":[]}'),
+  exportTasksAsCsv: vi.fn().mockReturnValue("id,title\n"),
+  exportMetricsAsJson: vi.fn().mockReturnValue('{"metrics":{}}'),
+  triggerDownload: vi.fn(),
+}));
+
+vi.mock("../../../store", () => ({
+  useStore: vi.fn((selector: (s: { tasks: Record<string, unknown> }) => unknown) => selector({ tasks: {} })),
+}));
+
+import { triggerDownload } from "../../../lib/export";
+const mockDownload = triggerDownload as ReturnType<typeof vi.fn>;
+
+describe("ExportButton", () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it("renders Export button", () => {
+    render(<ExportButton />);
+    expect(screen.getByText("Export")).toBeInTheDocument();
+  });
+
+  it("shows dropdown on click", () => {
+    render(<ExportButton />);
+    fireEvent.click(screen.getByText("Export"));
+    expect(screen.getByText("Tasks as JSON")).toBeInTheDocument();
+    expect(screen.getByText("Tasks as CSV")).toBeInTheDocument();
+  });
+
+  it("closes dropdown on second click", () => {
+    render(<ExportButton />);
+    fireEvent.click(screen.getByText("Export"));
+    fireEvent.click(screen.getByText("Export"));
+    expect(screen.queryByText("Tasks as JSON")).not.toBeInTheDocument();
+  });
+
+  it("calls triggerDownload with JSON when Tasks as JSON clicked", () => {
+    render(<ExportButton />);
+    fireEvent.click(screen.getByText("Export"));
+    fireEvent.click(screen.getByText("Tasks as JSON"));
+    expect(mockDownload).toHaveBeenCalledWith(expect.any(String), expect.stringContaining(".json"), "application/json");
+  });
+
+  it("calls triggerDownload with CSV when Tasks as CSV clicked", () => {
+    render(<ExportButton />);
+    fireEvent.click(screen.getByText("Export"));
+    fireEvent.click(screen.getByText("Tasks as CSV"));
+    expect(mockDownload).toHaveBeenCalledWith(expect.any(String), expect.stringContaining(".csv"), "text/csv");
+  });
+
+  it("shows Metrics as JSON option when metrics prop provided", () => {
+    const metrics = { total_cost_usd: 5, total_tasks: 2, cost_by_agent: {}, cost_by_day: [] };
+    render(<ExportButton metrics={metrics} />);
+    fireEvent.click(screen.getByText("Export"));
+    expect(screen.getByText("Metrics as JSON")).toBeInTheDocument();
+  });
+
+  it("hides Metrics as JSON option when no metrics prop", () => {
+    render(<ExportButton />);
+    fireEvent.click(screen.getByText("Export"));
+    expect(screen.queryByText("Metrics as JSON")).not.toBeInTheDocument();
+  });
+
+  it("calls triggerDownload when Metrics as JSON clicked", () => {
+    const metrics = { total_cost_usd: 5, total_tasks: 2, cost_by_agent: {}, cost_by_day: [] };
+    render(<ExportButton metrics={metrics} />);
+    fireEvent.click(screen.getByText("Export"));
+    fireEvent.click(screen.getByText("Metrics as JSON"));
+    expect(mockDownload).toHaveBeenCalledWith(expect.any(String), expect.stringContaining(".json"), "application/json");
+  });
+});