diff --git a/src/components/bookmarks/item.test.jsx b/src/components/bookmarks/item.test.jsx
new file mode 100644
index 000000000..38a5be3f9
--- /dev/null
+++ b/src/components/bookmarks/item.test.jsx
@@ -0,0 +1,32 @@
+// @vitest-environment jsdom
+
+import { screen } from "@testing-library/react";
+import { describe, expect, it, vi } from "vitest";
+
+import { renderWithProviders } from "test-utils/render-with-providers";
+
+vi.mock("components/resolvedicon", () => ({
+  default: ({ icon }) => <div data-testid="resolved-icon" data-icon={icon} />,
+}));
+
+import Item from "./item";
+
+describe("components/bookmarks/item", () => {
+  it("falls back description to href hostname and uses settings.target", () => {
+    renderWithProviders(<Item bookmark={{ name: "A", href: "http://example.com/x", abbr: "A" }} iconOnly={false} />, {
+      settings: { target: "_self", cardBlur: "" },
+    });
+
+    expect(screen.getByText("example.com")).toBeInTheDocument();
+    expect(screen.getByRole("link").getAttribute("target")).toBe("_self");
+  });
+
+  it("renders icon-only layout with icon when provided", () => {
+    renderWithProviders(
+      <Item bookmark={{ name: "A", href: "http://example.com/x", abbr: "A", icon: "mdi-home" }} iconOnly />,
+      { settings: { target: "_self" } },
+    );
+
+    expect(screen.getByTestId("resolved-icon").getAttribute("data-icon")).toBe("mdi-home");
+  });
+});
diff --git a/src/components/bookmarks/list.test.jsx b/src/components/bookmarks/list.test.jsx
new file mode 100644
index 000000000..60dd26025
--- /dev/null
+++ b/src/components/bookmarks/list.test.jsx
@@ -0,0 +1,38 @@
+// @vitest-environment jsdom
+
+import { render } from "@testing-library/react";
+import { beforeEach, describe, expect, it, vi } from "vitest";
+
+const { Item } = vi.hoisted(() => ({
+  Item: vi.fn(({ bookmark, iconOnly }) => (
+    <li data-testid="bookmark-item" data-name={bookmark.name} data-icononly={String(iconOnly)} />
+  )),
+}));
+
+vi.mock("components/bookmarks/item", () => ({
+  default: Item,
+}));
+
+import List from "./list";
+
+describe("components/bookmarks/list", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  it("renders items with iconOnly when iconsOnly is set", () => {
+    render(<List bookmarks={[{ name: "A", href: "http://a" }]} layout={{ iconsOnly: true }} bookmarksStyle="text" />);
+
+    expect(Item).toHaveBeenCalled();
+    expect(Item.mock.calls[0][0].iconOnly).toBe(true);
+  });
+
+  it("applies gridTemplateColumns in icons style", () => {
+    const { container } = render(
+      <List bookmarks={[{ name: "A", href: "http://a" }]} layout={{ header: false }} bookmarksStyle="icons" />,
+    );
+
+    const ul = container.querySelector("ul");
+    expect(ul.style.gridTemplateColumns).toContain("minmax(60px");
+  });
+});
diff --git a/src/components/errorboundry.test.jsx b/src/components/errorboundry.test.jsx
new file mode 100644
index 000000000..8f2c47368
--- /dev/null
+++ b/src/components/errorboundry.test.jsx
@@ -0,0 +1,38 @@
+// @vitest-environment jsdom
+
+import { render, screen } from "@testing-library/react";
+import { describe, expect, it, vi } from "vitest";
+
+import ErrorBoundary from "./errorboundry";
+
+describe("components/errorboundry", () => {
+  it("renders children when no error is thrown", () => {
+    render(
+      <ErrorBoundary>
+        <div>ok</div>
+      </ErrorBoundary>,
+    );
+
+    expect(screen.getByText("ok")).toBeInTheDocument();
+  });
+
+  it("renders a fallback UI when a child throws", () => {
+    const consoleSpy = vi.spyOn(console, "error").mockImplementation(() => {});
+    try {
+      const Boom = () => {
+        throw new Error("boom");
+      };
+
+      render(
+        <ErrorBoundary>
+          <Boom />
+        </ErrorBoundary>,
+      );
+
+      expect(screen.getByText("Something went wrong.")).toBeInTheDocument();
+      expect(screen.getByText("Error: boom")).toBeInTheDocument();
+    } finally {
+      consoleSpy.mockRestore();
+    }
+  });
+});
diff --git a/src/components/favicon.test.jsx b/src/components/favicon.test.jsx
new file mode 100644
index 000000000..c7a1d8c4c
--- /dev/null
+++ b/src/components/favicon.test.jsx
@@ -0,0 +1,39 @@
+// @vitest-environment jsdom
+
+import { render, waitFor } from "@testing-library/react";
+import { describe, expect, it, vi } from "vitest";
+
+import { ColorContext } from "utils/contexts/color";
+
+import Favicon from "./favicon";
+
+describe("components/favicon", () => {
+  it("appends a shortcut icon link after rendering the SVG to canvas", async () => {
+    const drawImage = vi.fn();
+    const getContextSpy = vi.spyOn(HTMLCanvasElement.prototype, "getContext").mockReturnValue({ drawImage });
+    const toDataURLSpy = vi
+      .spyOn(HTMLCanvasElement.prototype, "toDataURL")
+      .mockReturnValue("data:image/x-icon;base64,AAA");
+
+    const { container } = render(
+      <ColorContext.Provider value={{ color: "slate", setColor: vi.fn() }}>
+        <Favicon />
+      </ColorContext.Provider>,
+    );
+
+    const img = container.querySelector("img");
+    await waitFor(() => {
+      expect(typeof img.onload).toBe("function");
+    });
+
+    img.onload();
+
+    const link = document.head.querySelector('link[rel="shortcut icon"]');
+    expect(link).not.toBeNull();
+    expect(link.getAttribute("href")).toBe("data:image/x-icon;base64,AAA");
+    expect(drawImage).toHaveBeenCalled();
+
+    getContextSpy.mockRestore();
+    toDataURLSpy.mockRestore();
+  });
+});
diff --git a/src/components/resolvedicon.test.jsx b/src/components/resolvedicon.test.jsx
new file mode 100644
index 000000000..79f853017
--- /dev/null
+++ b/src/components/resolvedicon.test.jsx
@@ -0,0 +1,50 @@
+// @vitest-environment jsdom
+
+import { render, screen } from "@testing-library/react";
+import { describe, expect, it, vi } from "vitest";
+
+import { SettingsContext } from "utils/contexts/settings";
+import { ThemeContext } from "utils/contexts/theme";
+
+vi.mock("next/image", () => ({
+  default: ({ src, alt }) => <div data-testid="next-image" data-src={src} data-alt={alt} />,
+}));
+
+import ResolvedIcon from "./resolvedicon";
+
+function renderWithContexts(ui, { settings = {}, theme = "dark" } = {}) {
+  return render(
+    <SettingsContext.Provider value={{ settings, setSettings: () => {} }}>
+      <ThemeContext.Provider value={{ theme, setTheme: vi.fn() }}>{ui}</ThemeContext.Provider>
+    </SettingsContext.Provider>,
+  );
+}
+
+describe("components/resolvedicon", () => {
+  it("renders direct URL icons via next/image", () => {
+    renderWithContexts(<ResolvedIcon icon="http://example.com/x.png" alt="x" />);
+    expect(screen.getByTestId("next-image").getAttribute("data-src")).toBe("http://example.com/x.png");
+  });
+
+  it("renders selfh.st icons for sh- prefix with extension", () => {
+    renderWithContexts(<ResolvedIcon icon="sh-test.webp" alt="x" />);
+    expect(screen.getByTestId("next-image").getAttribute("data-src")).toContain("/webp/test.webp");
+  });
+
+  it("renders mdi icons as a masked div and supports custom hex colors", () => {
+    const { container } = renderWithContexts(<ResolvedIcon icon="mdi-home-#ff00ff" />, {
+      settings: { iconStyle: "theme" },
+      theme: "dark",
+    });
+
+    const div = container.querySelector("div");
+    // Browser normalizes hex colors to rgb() strings on assignment.
+    expect(div.style.background).toMatch(/(#ff00ff|rgb\(255, 0, 255\))/);
+    expect(div.getAttribute("style")).toContain("home.svg");
+  });
+
+  it("falls back to dashboard-icons for .svg", () => {
+    renderWithContexts(<ResolvedIcon icon="foo.svg" />);
+    expect(screen.getByTestId("next-image").getAttribute("data-src")).toContain("/dashboard-icons/svg/foo.svg");
+  });
+});
diff --git a/src/components/tab.test.jsx b/src/components/tab.test.jsx
new file mode 100644
index 000000000..87fa9e6ca
--- /dev/null
+++ b/src/components/tab.test.jsx
@@ -0,0 +1,32 @@
+// @vitest-environment jsdom
+
+import { fireEvent, render, screen } from "@testing-library/react";
+import { describe, expect, it, vi } from "vitest";
+
+import { TabContext } from "utils/contexts/tab";
+
+import Tab, { slugifyAndEncode } from "./tab";
+
+describe("components/tab", () => {
+  it("slugifyAndEncode lowercases and encodes spaces", () => {
+    expect(slugifyAndEncode("My Tab")).toBe("my-tab");
+    expect(slugifyAndEncode(undefined)).toBe("");
+  });
+
+  it("marks the matching tab as selected and updates hash on click", () => {
+    const setActiveTab = vi.fn();
+
+    render(
+      <TabContext.Provider value={{ activeTab: "my-tab", setActiveTab }}>
+        <Tab tab="My Tab" />
+      </TabContext.Provider>,
+    );
+
+    const btn = screen.getByRole("tab");
+    expect(btn.getAttribute("aria-selected")).toBe("true");
+
+    fireEvent.click(btn);
+    expect(setActiveTab).toHaveBeenCalledWith("my-tab");
+    expect(window.location.hash).toBe("#my-tab");
+  });
+});
diff --git a/src/components/toggles/color.test.jsx b/src/components/toggles/color.test.jsx
new file mode 100644
index 000000000..bb96322ba
--- /dev/null
+++ b/src/components/toggles/color.test.jsx
@@ -0,0 +1,59 @@
+// @vitest-environment jsdom
+
+import { fireEvent, render, screen } from "@testing-library/react";
+import { describe, expect, it, vi } from "vitest";
+
+import { ColorContext } from "utils/contexts/color";
+
+// Stub Popover/Transition to always render children.
+vi.mock("@headlessui/react", async () => {
+  const React = await import("react");
+  const { Fragment } = React;
+
+  function passthrough({ as: As = "div", children, ...props }) {
+    if (As === Fragment) return <>{typeof children === "function" ? children({ open: true }) : children}</>;
+    const content = typeof children === "function" ? children({ open: true }) : children;
+    return <As {...props}>{content}</As>;
+  }
+
+  function Popover({ children }) {
+    return <div>{typeof children === "function" ? children({ open: true }) : children}</div>;
+  }
+  function PopoverButton(props) {
+    return <button type="button" {...props} />;
+  }
+  function PopoverPanel(props) {
+    return <div {...props} />;
+  }
+  Popover.Button = PopoverButton;
+  Popover.Panel = PopoverPanel;
+
+  return { Popover, Transition: passthrough };
+});
+
+import ColorToggle from "./color";
+
+describe("components/toggles/color", () => {
+  it("renders nothing when no active color is set", () => {
+    const { container } = render(
+      <ColorContext.Provider value={{ color: null, setColor: vi.fn() }}>
+        <ColorToggle />
+      </ColorContext.Provider>,
+    );
+    expect(container).toBeEmptyDOMElement();
+  });
+
+  it("invokes setColor when a color button is clicked", () => {
+    const setColor = vi.fn();
+    render(
+      <ColorContext.Provider value={{ color: "slate", setColor }}>
+        <ColorToggle />
+      </ColorContext.Provider>,
+    );
+
+    // Buttons contain a sr-only span with the color name.
+    const blue = screen.getByText("blue").closest("button");
+    fireEvent.click(blue);
+    expect(setColor).toHaveBeenCalledWith("blue");
+  });
+});
diff --git a/src/components/toggles/revalidate.test.jsx b/src/components/toggles/revalidate.test.jsx
new file mode 100644
index 000000000..57bd65284
--- /dev/null
+++ b/src/components/toggles/revalidate.test.jsx
@@ -0,0 +1,27 @@
+// @vitest-environment jsdom
+
+import { fireEvent, render } from "@testing-library/react";
+import { describe, expect, it, vi } from "vitest";
+
+import Revalidate from "./revalidate";
+
+describe("components/toggles/revalidate", () => {
+  it("calls /api/revalidate and reloads when ok", async () => {
+    const reload = vi.fn();
+    const fetchSpy = vi.spyOn(globalThis, "fetch").mockResolvedValueOnce({ ok: true });
+    vi.stubGlobal("location", { reload });
+
+    render(<Revalidate />);
+    const icon = document.querySelector("svg");
+    fireEvent.click(icon);
+
+    // allow promise chain to flush
+    await Promise.resolve();
+
+    expect(fetchSpy).toHaveBeenCalledWith("/api/revalidate");
+    expect(reload).toHaveBeenCalledTimes(1);
+
+    fetchSpy.mockRestore();
+    vi.unstubAllGlobals();
+  });
+});
diff --git a/src/components/toggles/theme.test.jsx b/src/components/toggles/theme.test.jsx
new file mode 100644
index 000000000..eecb2a4dc
--- /dev/null
+++ b/src/components/toggles/theme.test.jsx
@@ -0,0 +1,33 @@
+// @vitest-environment jsdom
+
+import { fireEvent, render } from "@testing-library/react";
+import { describe, expect, it, vi } from "vitest";
+
+import { ThemeContext } from "utils/contexts/theme";
+
+import ThemeToggle from "./theme";
+
+describe("components/toggles/theme", () => {
+  it("renders nothing when theme is missing", () => {
+    const { container } = render(
+      <ThemeContext.Provider value={{ theme: null, setTheme: vi.fn() }}>
+        <ThemeToggle />
+      </ThemeContext.Provider>,
+    );
+    expect(container).toBeEmptyDOMElement();
+  });
+
+  it("toggles from dark to light when clicked", () => {
+    const setTheme = vi.fn();
+    render(
+      <ThemeContext.Provider value={{ theme: "dark", setTheme }}>
+        <ThemeToggle />
+      </ThemeContext.Provider>,
+    );
+
+    // The toggle is a clickable icon rendered as an svg (react-icons).
+    const toggles = document.querySelectorAll("svg");
+    fireEvent.click(toggles[1]);
+    expect(setTheme).toHaveBeenCalledWith("light");
+  });
+});