refactor(ui): extract reusable component package

packages/ui/src/theme.test.ts

@@ -0,0 +1,56 @@
+import { describe, expect, test } from "vitest";
+import {
+  getNextUiTheme,
+  isUiTheme,
+  persistUiTheme,
+  resolveInitialUiTheme,
+  UI_THEME_STORAGE_KEY,
+} from "./theme";
+
+describe("UI theme preference", () => {
+  test("defaults to dark when no stored preference exists", () => {
+    const storage = new Map<string, string>();
+
+    expect(resolveInitialUiTheme(storage)).toBe("dark");
+  });
+
+  test("restores a valid stored preference", () => {
+    const storage = new Map<string, string>([[UI_THEME_STORAGE_KEY, "light"]]);
+
+    expect(resolveInitialUiTheme(storage)).toBe("light");
+  });
+
+  test("ignores invalid stored preferences", () => {
+    const storage = new Map<string, string>([[UI_THEME_STORAGE_KEY, "solarized"]]);
+
+    expect(resolveInitialUiTheme(storage)).toBe("dark");
+  });
+
+  test("falls back when stored preferences cannot be read", () => {
+    const storage = {
+      getItem() {
+        throw new Error("storage blocked");
+      },
+    };
+
+    expect(resolveInitialUiTheme(storage)).toBe("dark");
+  });
+
+  test("ignores persistence failures", () => {
+    const storage = {
+      setItem() {
+        throw new Error("quota exceeded");
+      },
+    };
+
+    expect(() => persistUiTheme("light", storage)).not.toThrow();
+  });
+
+  test("detects and toggles supported themes", () => {
+    expect(isUiTheme("light")).toBe(true);
+    expect(isUiTheme("dark")).toBe(true);
+    expect(isUiTheme("contrast")).toBe(false);
+    expect(getNextUiTheme("dark")).toBe("light");
+    expect(getNextUiTheme("light")).toBe("dark");
+  });
+});