diff --git a/packages/ui/src/components/category-filter/category-filter.test.tsx b/packages/ui/src/components/category-filter/category-filter.test.tsx
new file mode 100644
index 00000000..a05c3768
--- /dev/null
+++ b/packages/ui/src/components/category-filter/category-filter.test.tsx
@@ -0,0 +1,66 @@
+import { render, screen } from "@testing-library/react";
+import { describe, expect, it, vi } from "vitest";
+
+let mockPathname = "/en/design-systems";
+
+vi.mock("next/navigation", () => ({
+  usePathname: () => mockPathname,
+}));
+
+import { CategoryFilter } from "./category-filter";
+
+describe("CategoryFilter", () => {
+  it("renders nothing when there are no categories", () => {
+    const { container } = render(<CategoryFilter categories={[]} lang="en" />);
+
+    expect(container).toBeEmptyDOMElement();
+  });
+
+  it("deduplicates and sorts category labels", () => {
+    render(
+      <CategoryFilter
+        categories={["zeta", "alpha", "zeta", "design systems"]}
+        lang="en"
+      />,
+    );
+
+    expect(screen.getAllByText(/Alpha|Design systems|Zeta/)).toHaveLength(3);
+    expect(
+      screen.getAllByText(/Alpha|Design systems|Zeta/).map((node) => {
+        return node.textContent;
+      }),
+    ).toEqual(["Alpha", "Design systems", "Zeta"]);
+  });
+
+  it("slugifies category links with the active language", () => {
+    render(
+      <CategoryFilter categories={["Résumé Tips", "Data & AI"]} lang="fr" />,
+    );
+
+    expect(screen.getByText("Résumé Tips").closest("a")).toHaveAttribute(
+      "href",
+      "/fr/resume-tips",
+    );
+    expect(screen.getByText("Data & AI").closest("a")).toHaveAttribute(
+      "href",
+      "/fr/data-ai",
+    );
+  });
+
+  it("renders the selected category as a non-link badge", () => {
+    mockPathname = "/en/design-systems";
+
+    render(
+      <CategoryFilter
+        categories={["design systems", "components"]}
+        lang="en"
+      />,
+    );
+
+    expect(screen.getByText("Design systems").closest("a")).toBeNull();
+    expect(screen.getByText("Components").closest("a")).toHaveAttribute(
+      "href",
+      "/en/components",
+    );
+  });
+});
diff --git a/packages/ui/src/components/content-intro/content-intro.test.tsx b/packages/ui/src/components/content-intro/content-intro.test.tsx
new file mode 100644
index 00000000..74be5649
--- /dev/null
+++ b/packages/ui/src/components/content-intro/content-intro.test.tsx
@@ -0,0 +1,76 @@
+import { fireEvent, render, screen } from "@testing-library/react";
+import { describe, expect, it, vi } from "vitest";
+
+import { ContentIntro, type ContentIntroSection } from "./content-intro";
+
+const sections: ContentIntroSection[] = [
+  { id: "setup", title: "Set up the workspace" },
+  { id: "ship", title: "Ship the first flow" },
+];
+
+const baseProps = {
+  completedSections: new Set<string>(),
+  estimatedTime: "12 min",
+  onGoToSection: vi.fn(),
+  onStart: vi.fn(),
+  renderIntroContent: () => <p>Read the framing first.</p>,
+  sections,
+  title: "Build a tutorial",
+};
+
+describe("ContentIntro", () => {
+  it("renders the intro content and table of contents", () => {
+    render(<ContentIntro {...baseProps} />);
+
+    expect(screen.getByText("Build a tutorial")).toBeInTheDocument();
+    expect(screen.getByText("Read the framing first.")).toBeInTheDocument();
+    expect(screen.getByText("Set up the workspace")).toBeInTheDocument();
+    expect(screen.getByText("Ship the first flow")).toBeInTheDocument();
+  });
+
+  it("calls onGoToSection with the clicked section index", () => {
+    const handleGoToSection = vi.fn();
+    render(<ContentIntro {...baseProps} onGoToSection={handleGoToSection} />);
+
+    fireEvent.click(screen.getByText("Ship the first flow"));
+
+    expect(handleGoToSection).toHaveBeenCalledWith(1);
+  });
+
+  it("shows progress and continue copy when sections are completed", () => {
+    render(
+      <ContentIntro
+        {...baseProps}
+        completedSections={new Set(["setup"])}
+        labels={{ continueLabel: "Keep going" }}
+      />,
+    );
+
+    expect(screen.getByText("1/2 completed")).toBeInTheDocument();
+    expect(screen.getByText("Keep going")).toBeInTheDocument();
+    expect(screen.getByText("Set up the workspace")).toHaveClass(
+      "line-through",
+    );
+  });
+
+  it("calls onStart from the primary button and Enter shortcut", () => {
+    const handleStart = vi.fn();
+    render(<ContentIntro {...baseProps} onStart={handleStart} />);
+
+    fireEvent.click(screen.getByText("Start Tutorial"));
+    fireEvent.keyDown(document, { key: "Enter" });
+
+    expect(handleStart).toHaveBeenCalledTimes(2);
+  });
+
+  it("renders additional content when supplied", () => {
+    render(
+      <ContentIntro
+        {...baseProps}
+        additionalContent={<aside>Author notes</aside>}
+      />,
+    );
+
+    expect(screen.getByText("Author notes")).toBeInTheDocument();
+  });
+});
diff --git a/packages/ui/src/components/table-of-contents-panel/table-of-contents-panel.test.tsx b/packages/ui/src/components/table-of-contents-panel/table-of-contents-panel.test.tsx
new file mode 100644
index 00000000..8ef6aeeb
--- /dev/null
+++ b/packages/ui/src/components/table-of-contents-panel/table-of-contents-panel.test.tsx
@@ -0,0 +1,93 @@
+import { fireEvent, render, screen } from "@testing-library/react";
+import { describe, expect, it, vi } from "vitest";
+
+import {
+  TableOfContentsPanel,
+  type TOCSection,
+} from "./table-of-contents-panel";
+
+const sections: TOCSection[] = [
+  { id: "intro", title: "Introduction" },
+  { id: "deep-dive", title: "Deep dive" },
+];
+
+const baseProps = {
+  completedSections: new Set<string>(["intro"]),
+  completionCount: 1,
+  currentSectionIndex: 0,
+  isOpen: true,
+  onClose: vi.fn(),
+  onSelectSection: vi.fn(),
+  sections,
+  totalSections: 2,
+};
+
+describe("TableOfContentsPanel", () => {
+  it("renders nothing when closed", () => {
+    render(<TableOfContentsPanel {...baseProps} isOpen={false} />);
+
+    expect(screen.queryByRole("dialog")).not.toBeInTheDocument();
+  });
+
+  it("renders the dialog with progress and sections when open", () => {
+    render(<TableOfContentsPanel {...baseProps} />);
+
+    expect(screen.getByRole("dialog")).toHaveAttribute("aria-modal", "true");
+    expect(screen.getByText("Table of Contents")).toBeInTheDocument();
+    expect(screen.getByText("1 / 2 (50%)")).toBeInTheDocument();
+    expect(screen.getByText("Introduction")).toBeInTheDocument();
+    expect(screen.getByText("Deep dive")).toBeInTheDocument();
+  });
+
+  it("selects a section and closes the panel", () => {
+    const handleClose = vi.fn();
+    const handleSelectSection = vi.fn();
+    render(
+      <TableOfContentsPanel
+        {...baseProps}
+        onClose={handleClose}
+        onSelectSection={handleSelectSection}
+      />,
+    );
+
+    fireEvent.click(screen.getByText("Deep dive"));
+
+    expect(handleSelectSection).toHaveBeenCalledWith(1);
+    expect(handleClose).toHaveBeenCalledTimes(1);
+  });
+
+  it("closes on Escape and backdrop click", () => {
+    const handleClose = vi.fn();
+    const { container } = render(
+      <TableOfContentsPanel {...baseProps} onClose={handleClose} />,
+    );
+    const backdrop = container.querySelector<HTMLElement>(
+      "[aria-hidden='true']",
+    );
+    if (!backdrop) throw new Error("Expected backdrop to render");
+
+    fireEvent.keyDown(window, { key: "Escape" });
+    fireEvent.click(backdrop);
+
+    expect(handleClose).toHaveBeenCalledTimes(2);
+  });
+
+  it("renders the reset action only when progress exists", () => {
+    const handleReset = vi.fn();
+    const { rerender } = render(
+      <TableOfContentsPanel {...baseProps} onReset={handleReset} />,
+    );
+
+    fireEvent.click(screen.getByText("Reset Progress"));
+    expect(handleReset).toHaveBeenCalledTimes(1);
+
+    rerender(
+      <TableOfContentsPanel
+        {...baseProps}
+        completionCount={0}
+        onReset={handleReset}
+      />,
+    );
+    expect(screen.queryByText("Reset Progress")).not.toBeInTheDocument();
+  });
+});
diff --git a/packages/ui/src/components/tutorial-filters/tutorial-filters.test.tsx b/packages/ui/src/components/tutorial-filters/tutorial-filters.test.tsx
new file mode 100644
index 00000000..8b219185
--- /dev/null
+++ b/packages/ui/src/components/tutorial-filters/tutorial-filters.test.tsx
@@ -0,0 +1,119 @@
+import { fireEvent, render, screen } from "@testing-library/react";
+import { describe, expect, it, vi } from "vitest";
+
+import {
+  TutorialFilters,
+  type TutorialFiltersLabels,
+} from "./tutorial-filters";
+
+const labels: TutorialFiltersLabels = {
+  activeFilters: "Active filters:",
+  clear: "Clear",
+  clearAll: "Clear all",
+  difficulty: {
+    advanced: "Advanced",
+    all: "All",
+    beginner: "Beginner",
+    intermediate: "Intermediate",
+  },
+  difficultyLabel: "Difficulty",
+  searchFilter: "Search",
+  searchLabel: "Search tutorials",
+  searchPlaceholder: "Search by topic",
+  tagsLabel: "Tags",
+};
+
+const baseProps = {
+  currentDifficulty: "",
+  currentTags: [] as string[],
+  labels,
+  onFilterChange: vi.fn(),
+  searchQuery: "",
+  tags: ["React", "Design"],
+};
+
+describe("TutorialFilters", () => {
+  it("renders search, difficulty options, and tags", () => {
+    render(<TutorialFilters {...baseProps} />);
+
+    expect(screen.getByLabelText("Search tutorials")).toHaveAttribute(
+      "placeholder",
+      "Search by topic",
+    );
+    expect(screen.getByText("Beginner")).toBeInTheDocument();
+    expect(screen.getByText("Advanced")).toBeInTheDocument();
+    expect(screen.getByText("React")).toBeInTheDocument();
+    expect(screen.getByText("Design")).toBeInTheDocument();
+  });
+
+  it("emits search and difficulty updates", () => {
+    const handleFilterChange = vi.fn();
+    render(
+      <TutorialFilters {...baseProps} onFilterChange={handleFilterChange} />,
+    );
+
+    fireEvent.change(screen.getByLabelText("Search tutorials"), {
+      target: { value: "state" },
+    });
+    fireEvent.click(screen.getByText("Intermediate"));
+
+    expect(handleFilterChange).toHaveBeenCalledWith({ search: "state" });
+    expect(handleFilterChange).toHaveBeenCalledWith({
+      difficulty: "intermediate",
+    });
+  });
+
+  it("toggles tags from the current selection", () => {
+    const handleFilterChange = vi.fn();
+    render(
+      <TutorialFilters
+        {...baseProps}
+        currentTags={["React"]}
+        onFilterChange={handleFilterChange}
+      />,
+    );
+    const [reactTag] = screen.getAllByText("React");
+    if (!reactTag) throw new Error("Expected React tag to render");
+
+    fireEvent.click(reactTag);
+    fireEvent.click(screen.getByText("Design"));
+
+    expect(handleFilterChange).toHaveBeenCalledWith({ tags: [] });
+    expect(handleFilterChange).toHaveBeenCalledWith({
+      tags: ["React", "Design"],
+    });
+  });
+
+  it("renders active filters and clears them", () => {
+    const handleFilterChange = vi.fn();
+    render(
+      <TutorialFilters
+        {...baseProps}
+        currentDifficulty="advanced"
+        currentTags={["React"]}
+        onFilterChange={handleFilterChange}
+        searchQuery="routing"
+      />,
+    );
+
+    expect(screen.getByText("Active filters:")).toBeInTheDocument();
+    expect(screen.getByText('Search "routing"')).toBeInTheDocument();
+
+    fireEvent.click(screen.getByText("Clear"));
+    fireEvent.click(screen.getByText("Clear all"));
+
+    expect(handleFilterChange).toHaveBeenCalledWith({ tags: [] });
+    expect(handleFilterChange).toHaveBeenCalledWith({
+      difficulty: "all",
+      search: "",
+      tags: [],
+    });
+  });
+
+  it("disables search and difficulty controls while pending", () => {
+    render(<TutorialFilters {...baseProps} isPending />);
+
+    expect(screen.getByLabelText("Search tutorials")).toBeDisabled();
+    expect(screen.getByText("Beginner").closest("button")).toBeDisabled();
+  });
+});
diff --git a/packages/ui/src/components/tutorial-intro-content/tutorial-intro-content.test.tsx b/packages/ui/src/components/tutorial-intro-content/tutorial-intro-content.test.tsx
new file mode 100644
index 00000000..697f5baf
--- /dev/null
+++ b/packages/ui/src/components/tutorial-intro-content/tutorial-intro-content.test.tsx
@@ -0,0 +1,64 @@
+import { render, screen } from "@testing-library/react";
+import { describe, expect, it } from "vitest";
+
+import { TutorialIntroContent } from "./tutorial-intro-content";
+
+describe("TutorialIntroContent", () => {
+  it("renders the supplied title and markdown content", () => {
+    render(
+      <TutorialIntroContent
+        content="Intro paragraph with **strong text**."
+        title="Start here"
+      />,
+    );
+
+    expect(screen.getByRole("heading", { name: "Start here" })).toBeVisible();
+    expect(screen.getByText(/Intro paragraph with/)).toBeInTheDocument();
+    expect(screen.getByText("strong text")).toHaveClass("font-semibold");
+  });
+
+  it("renders links and inline code with the expected semantics", () => {
+    render(
+      <TutorialIntroContent
+        content="Use [`pnpm`](https://pnpm.io) for installs."
+        title="Setup"
+      />,
+    );
+
+    expect(screen.getByText("pnpm").tagName).toBe("CODE");
+    expect(screen.getByText("pnpm").closest("a")).toHaveAttribute(
+      "href",
+      "https://pnpm.io",
+    );
+  });
+
+  it("strips MDX component tags before markdown rendering", () => {
+    render(
+      <TutorialIntroContent
+        content={[
+          "Visible copy.",
+          "<Callout>Hidden client-only content</Callout>",
+          "<Badge />",
+        ].join("\n\n")}
+        title="Hybrid content"
+      />,
+    );
+
+    expect(screen.getByText("Visible copy.")).toBeInTheDocument();
+    expect(
+      screen.queryByText("Hidden client-only content"),
+    ).not.toBeInTheDocument();
+  });
+
+  it("applies a custom class name to the section", () => {
+    const { container } = render(
+      <TutorialIntroContent
+        className="custom-intro"
+        content="Body"
+        title="Intro"
+      />,
+    );
+
+    expect(container.querySelector("section")).toHaveClass("custom-intro");
+  });
+});