test(coverage): bootstrap vitest unit infra and add tests at 90%+ per file (#1245) (#1269)

* test(coverage): bootstrap vitest unit infra and add tests at 90%+ per file (#1245)

Establishes the unit-test runtime AGENTS.md mandates: a vitest "unit"
project alongside the existing storybook project, RTL + jest-dom +
happy-dom, a Mantine-aware render helper, and a 90%-line per-file
coverage gate enforced by CI. Adds 66 test files covering all 62
components under elements/groups/screens/views, plus core/mcp and
clients/web/src/utils. Total: 577 tests, 98.7% line coverage globally.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* test(coverage): address PR #1269 review feedback

- AGENTS.md: correct coverage gate description (lines ≥ 90, statements ≥ 85,
  functions ≥ 80, branches ≥ 50) with rationale for the relaxed branch
  threshold
- InspectorView.test.tsx: document what the Math.random() mock values
  (0.1 / 0.99) control vs. STUB_SUCCESS_RATE in InspectorView.tsx
- vite.config.ts / tsconfig.test.json: drop unused `globals: true` and the
  `vitest/globals` type now that every test file imports describe/it/expect/vi
  explicitly; manual `afterEach(cleanup)` in setup.ts remains required because
  testing-library auto-cleanup relies on globalThis.afterEach

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

clients/web/src/components/groups/ResourcePreviewPanel/ResourcePreviewPanel.test.tsx

@@ -0,0 +1,202 @@
+import { describe, it, expect, vi } from "vitest";
+import userEvent from "@testing-library/user-event";
+import type {
+  BlobResourceContents,
+  Resource,
+  TextResourceContents,
+} from "@modelcontextprotocol/sdk/types.js";
+import { renderWithMantine, screen } from "../../../test/renderWithMantine";
+import { ResourcePreviewPanel } from "./ResourcePreviewPanel";
+
+const textResource: Resource = {
+  name: "config.json",
+  uri: "file:///config.json",
+};
+
+const textContents: TextResourceContents[] = [
+  {
+    uri: "file:///config.json",
+    mimeType: "application/json",
+    text: '{"a":1}',
+  },
+];
+
+const imageBlob: BlobResourceContents = {
+  uri: "file:///x.png",
+  mimeType: "image/png",
+  blob: "abc",
+};
+
+const audioBlob: BlobResourceContents = {
+  uri: "file:///x.wav",
+  mimeType: "audio/wav",
+  blob: "abc",
+};
+
+const otherBlob: BlobResourceContents = {
+  uri: "file:///x.bin",
+  mimeType: "application/octet-stream",
+  blob: "abc",
+};
+
+const blobNoMime: BlobResourceContents = {
+  uri: "file:///x",
+  blob: "abc",
+};
+
+const baseProps = {
+  resource: textResource,
+  contents: textContents,
+  isSubscribed: false,
+  onRefresh: vi.fn(),
+  onSubscribe: vi.fn(),
+  onUnsubscribe: vi.fn(),
+};
+
+describe("ResourcePreviewPanel", () => {
+  it("renders the resource title and URI", () => {
+    renderWithMantine(<ResourcePreviewPanel {...baseProps} />);
+    expect(screen.getByText("Resource")).toBeInTheDocument();
+    expect(screen.getByText("file:///config.json")).toBeInTheDocument();
+  });
+
+  it("renders the mimeType when contents has at most one item", () => {
+    renderWithMantine(<ResourcePreviewPanel {...baseProps} />);
+    expect(screen.getByText("application/json")).toBeInTheDocument();
+  });
+
+  it("does not render mimeType when there are multiple content items", () => {
+    renderWithMantine(
+      <ResourcePreviewPanel
+        {...baseProps}
+        contents={[textContents[0], textContents[0]]}
+      />,
+    );
+    expect(screen.queryByText("application/json")).not.toBeInTheDocument();
+  });
+
+  it("renders the lastUpdated timestamp when provided", () => {
+    renderWithMantine(
+      <ResourcePreviewPanel
+        {...baseProps}
+        lastUpdated={new Date("2026-03-17T10:30:00Z")}
+      />,
+    );
+    expect(screen.getByText(/^Last updated:/)).toBeInTheDocument();
+  });
+
+  it("renders Subscribe button when not subscribed and triggers onSubscribe", async () => {
+    const user = userEvent.setup();
+    const onSubscribe = vi.fn();
+    renderWithMantine(
+      <ResourcePreviewPanel {...baseProps} onSubscribe={onSubscribe} />,
+    );
+    await user.click(screen.getByRole("button", { name: "Subscribe" }));
+    expect(onSubscribe).toHaveBeenCalledTimes(1);
+  });
+
+  it("renders Unsubscribe button when subscribed and triggers onUnsubscribe", async () => {
+    const user = userEvent.setup();
+    const onUnsubscribe = vi.fn();
+    renderWithMantine(
+      <ResourcePreviewPanel
+        {...baseProps}
+        isSubscribed
+        onUnsubscribe={onUnsubscribe}
+      />,
+    );
+    await user.click(screen.getByRole("button", { name: "Unsubscribe" }));
+    expect(onUnsubscribe).toHaveBeenCalledTimes(1);
+  });
+
+  it("invokes onRefresh when Refresh is clicked", async () => {
+    const user = userEvent.setup();
+    const onRefresh = vi.fn();
+    renderWithMantine(
+      <ResourcePreviewPanel {...baseProps} onRefresh={onRefresh} />,
+    );
+    await user.click(screen.getByRole("button", { name: "Refresh" }));
+    expect(onRefresh).toHaveBeenCalledTimes(1);
+  });
+
+  it("renders annotation badges when present", () => {
+    renderWithMantine(
+      <ResourcePreviewPanel
+        {...baseProps}
+        resource={{
+          ...textResource,
+          annotations: { audience: ["user"], priority: 0.8 },
+        }}
+      />,
+    );
+    expect(screen.getByText("audience: user")).toBeInTheDocument();
+    expect(screen.getByText("priority: high")).toBeInTheDocument();
+  });
+
+  it("renders an image content viewer for image blobs", () => {
+    renderWithMantine(
+      <ResourcePreviewPanel
+        {...baseProps}
+        resource={{ name: "img", uri: "file:///x.png" }}
+        contents={[imageBlob]}
+      />,
+    );
+    const img = screen
+      .getAllByRole("img")
+      .find((el) => el.getAttribute("src")?.startsWith("data:image/png"));
+    expect(img).toBeDefined();
+  });
+
+  it("renders an audio element for audio blobs", () => {
+    const { container } = renderWithMantine(
+      <ResourcePreviewPanel
+        {...baseProps}
+        resource={{ name: "snd", uri: "file:///x.wav" }}
+        contents={[audioBlob]}
+      />,
+    );
+    const audio = container.querySelector("audio");
+    expect(audio).not.toBeNull();
+  });
+
+  it("renders a textual unsupported message for non-image, non-audio blobs", () => {
+    renderWithMantine(
+      <ResourcePreviewPanel
+        {...baseProps}
+        resource={{ name: "bin", uri: "file:///x.bin" }}
+        contents={[otherBlob]}
+      />,
+    );
+    expect(
+      screen.getByText(
+        "[Binary content (application/octet-stream) — preview not supported]",
+      ),
+    ).toBeInTheDocument();
+  });
+
+  it("falls back to application/octet-stream when blob has no mimeType", () => {
+    renderWithMantine(
+      <ResourcePreviewPanel
+        {...baseProps}
+        resource={{ name: "bin", uri: "file:///x" }}
+        contents={[blobNoMime]}
+      />,
+    );
+    expect(screen.getByText("application/octet-stream")).toBeInTheDocument();
+  });
+
+  it("falls back to resource.mimeType when contents is empty", () => {
+    renderWithMantine(
+      <ResourcePreviewPanel
+        {...baseProps}
+        resource={{
+          name: "x",
+          uri: "file:///x",
+          mimeType: "text/markdown",
+        }}
+        contents={[]}
+      />,
+    );
+    expect(screen.getByText("text/markdown")).toBeInTheDocument();
+  });
+});