diff --git a/packages/ui/src/utils/__test__/country-picker.test.ts b/packages/ui/src/utils/__test__/country-picker.test.ts
new file mode 100644
index 000000000..ff5952eaf
--- /dev/null
+++ b/packages/ui/src/utils/__test__/country-picker.test.ts
@@ -0,0 +1,129 @@
+import { describe, expect, test } from "vitest";
+
+import defaultEnglishTranslation from "../../FormWidgets/CountryPicker/en.json";
+import { getFallbackTranslation, getFlagClass } from "../country-picker";
+
+const frenchTranslation = {
+  DE: "Allemagne",
+  BR: "Brésil",
+  CA: "Canada",
+  CN: "Chine",
+  ES: "Espagne",
+  US: "États‑Unis",
+  FR: "France",
+  IT: "Italie",
+  JP: "Japon",
+  GB: "Royaume‑Uni",
+  RU: "Russie",
+};
+
+const spanishTranslation = {
+  DE: "Alemania",
+  BR: "Brasil",
+  CA: "Canadá",
+  CN: "China",
+  ES: "España",
+  US: "Estados Unidos",
+  FR: "Francia",
+  IT: "Italia",
+  JP: "Japón",
+  GB: "Reino Unido",
+  RU: "Rusia",
+};
+
+const locales = {
+  fr: frenchTranslation,
+  es: spanishTranslation,
+};
+
+describe("getFallbackTranslation", () => {
+  test("Should return translation from locales if fallbackLocale exists in it", () => {
+    const result = getFallbackTranslation("fr", locales);
+
+    expect(result).toEqual(frenchTranslation);
+  });
+
+  test("Should return defaultEnglishTranslation if fallbackLocale is 'en' and not in locales", () => {
+    const result = getFallbackTranslation("en", {});
+
+    expect(result).toEqual(defaultEnglishTranslation);
+  });
+
+  test("Should prioritize locales['en'] over defaultEnglishTranslation if provided", () => {
+    const englishTranslation = { FR: "France" };
+    const locales = { en: englishTranslation };
+    const result = getFallbackTranslation("en", locales);
+
+    expect(result).toEqual(englishTranslation);
+  });
+
+  test("Should return null if fallbackLocale is not found and is not 'en'", () => {
+    const result = getFallbackTranslation("de", locales);
+
+    expect(result).toBeNull();
+  });
+
+  test("Should handle undefined locales gracefully", () => {
+    const result = getFallbackTranslation("fr", undefined);
+
+    expect(result).toBeNull();
+  });
+
+  test("Should return defaultEnglishTranslation when locales is undefined but fallback is 'en'", () => {
+    const result = getFallbackTranslation("en", undefined);
+
+    expect(result).toEqual(defaultEnglishTranslation);
+  });
+});
+
+describe("getFlagClass", () => {
+  test("Should generate basic class with code only", () => {
+    const result = getFlagClass("US", "left", "normal");
+
+    expect(result).toBe("flag-icon flag-icon-us");
+  });
+
+  test("Should handle lowercase and trimming of country code", () => {
+    const result = getFlagClass("  GB  ", "left", "normal");
+
+    expect(result).toBe("flag-icon flag-icon-gb");
+  });
+
+  test("Should add 'flag-icon-right' when position is 'right'", () => {
+    const result = getFlagClass("fr", "right", "normal");
+
+    expect(result).toBe("flag-icon flag-icon-fr flag-icon-right");
+  });
+
+  test("Should add 'flag-icon-right-edge' when position is 'right-edge'", () => {
+    const result = getFlagClass("fr", "right-edge", "normal");
+
+    expect(result).toBe("flag-icon flag-icon-fr flag-icon-right-edge");
+  });
+
+  test("Should add 'flag-icon-rounded' when style is 'circle'", () => {
+    const result = getFlagClass("jp", "left", "circle");
+
+    expect(result).toBe("flag-icon flag-icon-jp flag-icon-rounded");
+  });
+
+  test("Should add 'flag-icon-squared' when style is 'square'", () => {
+    const result = getFlagClass("jp", "left", "square");
+
+    expect(result).toBe("flag-icon flag-icon-jp flag-icon-squared");
+  });
+
+  test("Should combine multiple classes correctly", () => {
+    const result = getFlagClass("ca", "right", "circle");
+
+    expect(result).toBe(
+      "flag-icon flag-icon-ca flag-icon-right flag-icon-rounded",
+    );
+  });
+
+  test("Should handle undefined code gracefully", () => {
+    const result = getFlagClass(undefined, "left", "normal");
+
+    expect(result).toBe("flag-icon");
+  });
+});