fix: add main landmark, skip link, and aria-label to canvas (WCAG 2.4.1/2.4.6)

canvas/src/components/Canvas.tsx

@@ -226,7 +226,14 @@ function CanvasInner() {
   const settingsWorkspaceId = selectedNodeId ?? "global";
 
   return (
-    <div className="w-screen h-screen bg-zinc-950">
+    <>
+      <a
+        href="#canvas-main"
+        className="sr-only focus:not-sr-only focus:absolute focus:top-2 focus:left-2 focus:z-50 focus:px-4 focus:py-2 focus:bg-zinc-900 focus:text-zinc-100 focus:rounded-lg focus:border focus:border-zinc-700"
+      >
+        Skip to canvas
+      </a>
+      <main id="canvas-main" className="w-screen h-screen bg-zinc-950">
       <ReactFlow
         colorMode="dark"
         nodes={nodes}
@@ -244,6 +251,7 @@ function CanvasInner() {
         minZoom={0.1}
         maxZoom={2}
         proOptions={{ hideAttribution: true }}
+        aria-label="Molecule AI workspace canvas"
       >
         <Background
           variant={BackgroundVariant.Dots}
@@ -310,6 +318,7 @@ function CanvasInner() {
       {/* Settings Panel — global secrets management drawer */}
       <SettingsPanel workspaceId={settingsWorkspaceId} />
       <DeleteConfirmDialog workspaceId={settingsWorkspaceId} />
-    </div>
+      </main>
+    </>
   );
 }

canvas/src/components/__tests__/Canvas.a11y.test.tsx

@@ -0,0 +1,138 @@
+// @vitest-environment jsdom
+import { describe, it, expect, vi, afterEach } from "vitest";
+import { render, screen, cleanup } from "@testing-library/react";
+
+afterEach(() => {
+  cleanup();
+});
+
+// ── Mock @xyflow/react ────────────────────────────────────────────────────────
+vi.mock("@xyflow/react", () => {
+  const ReactFlow = ({
+    children,
+    "aria-label": ariaLabel,
+  }: {
+    children?: React.ReactNode;
+    "aria-label"?: string;
+  }) => (
+    <div role="application" data-testid="react-flow" aria-label={ariaLabel}>
+      {children}
+    </div>
+  );
+  return {
+    __esModule: true,
+    default: ReactFlow,
+    ReactFlow,
+    ReactFlowProvider: ({ children }: { children?: React.ReactNode }) => (
+      <>{children}</>
+    ),
+    Background: () => null,
+    Controls: () => null,
+    MiniMap: () => null,
+    BackgroundVariant: { Dots: "dots" },
+    useReactFlow: () => ({
+      fitView: vi.fn(),
+      setViewport: vi.fn(),
+      getIntersectingNodes: vi.fn(() => []),
+      fitBounds: vi.fn(),
+      setCenter: vi.fn(),
+    }),
+    applyNodeChanges: vi.fn((_: unknown, nodes: unknown) => nodes),
+    useStore: vi.fn(() => ({ width: 800, height: 600 })),
+  };
+});
+
+// ── Mock the canvas store ─────────────────────────────────────────────────────
+const mockStoreState = {
+  nodes: [],
+  edges: [],
+  selectedNodeId: null,
+  panelTab: "chat",
+  dragOverNodeId: null,
+  contextMenu: null,
+  viewport: { x: 0, y: 0, zoom: 1 },
+  searchOpen: false,
+  onNodesChange: vi.fn(),
+  savePosition: vi.fn(),
+  saveViewport: vi.fn(),
+  selectNode: vi.fn(),
+  openContextMenu: vi.fn(),
+  closeContextMenu: vi.fn(),
+  setDragOverNode: vi.fn(),
+  nestNode: vi.fn(),
+  isDescendant: vi.fn(() => false),
+  setSearchOpen: vi.fn(),
+};
+
+vi.mock("@/store/canvas", () => ({
+  useCanvasStore: Object.assign(
+    vi.fn((selector: (s: typeof mockStoreState) => unknown) =>
+      selector(mockStoreState)
+    ),
+    { getState: () => mockStoreState }
+  ),
+}));
+
+// ── Mock the socket store ─────────────────────────────────────────────────────
+vi.mock("@/store/socket", () => ({
+  connectSocket: vi.fn(),
+  disconnectSocket: vi.fn(),
+}));
+
+// ── Mock all heavy child components to null ───────────────────────────────────
+vi.mock("../Toolbar", () => ({ Toolbar: () => null }));
+vi.mock("../SidePanel", () => ({ SidePanel: () => null }));
+vi.mock("../EmptyState", () => ({ EmptyState: () => null }));
+vi.mock("../ContextMenu", () => ({ ContextMenu: () => null }));
+vi.mock("../SearchDialog", () => ({ SearchDialog: () => null }));
+vi.mock("../ConfirmDialog", () => ({ ConfirmDialog: () => null }));
+vi.mock("../TemplatePalette", () => ({ TemplatePalette: () => null }));
+vi.mock("../OnboardingWizard", () => ({ OnboardingWizard: () => null }));
+vi.mock("../ApprovalBanner", () => ({ ApprovalBanner: () => null }));
+vi.mock("../BundleDropZone", () => ({ BundleDropZone: () => null }));
+vi.mock("../CreateWorkspaceDialog", () => ({ CreateWorkspaceButton: () => null }));
+vi.mock("../settings", () => ({
+  SettingsPanel: () => null,
+  DeleteConfirmDialog: () => null,
+}));
+vi.mock("../Toaster", () => ({ Toaster: () => null }));
+vi.mock("../WorkspaceNode", () => ({ WorkspaceNode: () => null }));
+
+// ── Import the component under test AFTER mocks ───────────────────────────────
+import { Canvas } from "../Canvas";
+
+describe("Canvas — accessibility landmarks", () => {
+  it("renders a <main> landmark with id='canvas-main'", () => {
+    render(<Canvas />);
+    const main = screen.getByRole("main");
+    expect(main).toBeTruthy();
+    expect(main.id).toBe("canvas-main");
+  });
+
+  it("renders a skip-to-content link pointing at #canvas-main", () => {
+    render(<Canvas />);
+    const skipLink = document.querySelector('a[href="#canvas-main"]');
+    expect(skipLink).toBeTruthy();
+    expect(skipLink?.textContent?.trim()).toBe("Skip to canvas");
+  });
+
+  it("ReactFlow wrapper receives aria-label describing the canvas", () => {
+    render(<Canvas />);
+    const flow = document.querySelector('[data-testid="react-flow"]');
+    expect(flow?.getAttribute("aria-label")).toBe(
+      "Molecule AI workspace canvas"
+    );
+  });
+
+  it("skip link appears before <main> in the DOM", () => {
+    render(<Canvas />);
+    const body = document.body;
+    const skipLink = body.querySelector('a[href="#canvas-main"]');
+    const main = body.querySelector("main");
+    expect(skipLink).toBeTruthy();
+    expect(main).toBeTruthy();
+    // skip link must come before main in the DOM order
+    const position = skipLink!.compareDocumentPosition(main!);
+    expect(position & Node.DOCUMENT_POSITION_FOLLOWING).toBeTruthy();
+  });
+});