test: add BatchActionBar unit tests (7 tests)

Covers: render threshold, count badge, action buttons, clear selection,
ConfirmDialog trigger, ARIA toolbar role.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

canvas/src/components/__tests__/BatchActionBar.test.tsx

@@ -0,0 +1,127 @@
+// @vitest-environment jsdom
+/**
+ * BatchActionBar tests — Phase 20.3
+ *
+ * Covers:
+ *   - Not rendered when fewer than 2 nodes selected
+ *   - Renders with correct count badge when 2+ selected
+ *   - Restart/Pause/Delete buttons exist with correct labels
+ *   - Clear selection button exists
+ *   - ConfirmDialog appears on destructive action click
+ */
+import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
+import { render, screen, fireEvent, cleanup } from "@testing-library/react";
+
+afterEach(() => {
+  cleanup();
+});
+
+// ── Mocks ────────────────────────────────────────────────────────────────────
+
+vi.mock("@/components/Toaster", () => ({
+  showToast: vi.fn(),
+}));
+
+const mockClearSelection = vi.fn();
+const mockBatchRestart = vi.fn(() => Promise.resolve());
+const mockBatchPause = vi.fn(() => Promise.resolve());
+const mockBatchDelete = vi.fn(() => Promise.resolve());
+
+let mockSelectedNodeIds = new Set<string>();
+
+vi.mock("@/store/canvas", () => ({
+  useCanvasStore: vi.fn((selector: (s: Record<string, unknown>) => unknown) =>
+    selector({
+      selectedNodeIds: mockSelectedNodeIds,
+      clearSelection: mockClearSelection,
+      batchRestart: mockBatchRestart,
+      batchPause: mockBatchPause,
+      batchDelete: mockBatchDelete,
+    })
+  ),
+}));
+
+// Mock ConfirmDialog to just render buttons for testing
+vi.mock("@/components/ConfirmDialog", () => ({
+  ConfirmDialog: ({
+    open,
+    title,
+    onConfirm,
+    onCancel,
+  }: {
+    open: boolean;
+    title: string;
+    confirmLabel: string;
+    message: string;
+    confirmVariant: string;
+    onConfirm: () => void;
+    onCancel: () => void;
+  }) =>
+    open ? (
+      <div data-testid="confirm-dialog">
+        <span>{title}</span>
+        <button onClick={onConfirm}>confirm</button>
+        <button onClick={onCancel}>cancel</button>
+      </div>
+    ) : null,
+}));
+
+// Import after mocks
+import { BatchActionBar } from "../BatchActionBar";
+
+// ── Tests ────────────────────────────────────────────────────────────────────
+
+describe("BatchActionBar", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+    mockSelectedNodeIds = new Set<string>();
+  });
+
+  it("does not render when fewer than 2 nodes selected", () => {
+    mockSelectedNodeIds = new Set(["ws-1"]);
+    const { container } = render(<BatchActionBar />);
+    expect(container.innerHTML).toBe("");
+  });
+
+  it("renders count badge when 2+ nodes selected", () => {
+    mockSelectedNodeIds = new Set(["ws-1", "ws-2", "ws-3"]);
+    render(<BatchActionBar />);
+    expect(screen.getByText("3 selected")).toBeTruthy();
+  });
+
+  it("renders Restart All, Pause All, Delete All buttons", () => {
+    mockSelectedNodeIds = new Set(["ws-1", "ws-2"]);
+    render(<BatchActionBar />);
+    expect(screen.getByText("Restart All")).toBeTruthy();
+    expect(screen.getByText("Pause All")).toBeTruthy();
+    expect(screen.getByText("Delete All")).toBeTruthy();
+  });
+
+  it("renders clear selection button with aria-label", () => {
+    mockSelectedNodeIds = new Set(["ws-1", "ws-2"]);
+    render(<BatchActionBar />);
+    const clearBtn = screen.getByRole("button", { name: "Clear selection" });
+    expect(clearBtn).toBeTruthy();
+  });
+
+  it("clicking clear selection calls clearSelection", () => {
+    mockSelectedNodeIds = new Set(["ws-1", "ws-2"]);
+    render(<BatchActionBar />);
+    fireEvent.click(screen.getByRole("button", { name: "Clear selection" }));
+    expect(mockClearSelection).toHaveBeenCalled();
+  });
+
+  it("clicking Delete All opens ConfirmDialog", () => {
+    mockSelectedNodeIds = new Set(["ws-1", "ws-2"]);
+    render(<BatchActionBar />);
+    fireEvent.click(screen.getByText("Delete All"));
+    expect(screen.getByTestId("confirm-dialog")).toBeTruthy();
+  });
+
+  it("has role=toolbar with aria-label", () => {
+    mockSelectedNodeIds = new Set(["ws-1", "ws-2"]);
+    render(<BatchActionBar />);
+    const toolbar = screen.getByRole("toolbar");
+    expect(toolbar.getAttribute("aria-label")).toBe("Batch workspace actions");
+  });
+});