test: add validation tests for platform-specific locale formats (#1585)

* docs: add changeset requirements to CLAUDE.md and create changeset

* test: add validation tests for platform-specific locale formats

Add comprehensive tests for localeCodeSchema validation to ensure
support for different platform-specific locale code formats:

- Standard BCP 47 format (en-US, zh-Hans-CN)
- Underscore format used by Java/Android (en_US, zh_Hans_CN)
- Android resource folder format with r-prefix (en-rUS, fr-rCA)

These tests verify that the normalizeLocale() function correctly
handles all common locale code variations before validation.

* fix: prettier formatting in provider.spec.tsx

Author: maxprilutskiy

.changeset/allow-valid-locale-codes.md

@@ -0,0 +1,5 @@
+---
+"@lingo.dev/_spec": minor
+---
+
+Allow any valid ISO locale code in validation instead of hardcoded list. Validation now accepts any locale conforming to ISO 639-1, ISO 15924, ISO 3166-1, and UN M.49 standards.

.changeset/honest-melons-judge.md

@@ -0,0 +1,4 @@
+---
+---
+
+Add comprehensive tests for platform-specific locale code formats (underscore and Android r-prefix)

packages/react/src/client/provider.spec.tsx

@@ -53,7 +53,10 @@ describe("client/provider", () => {
 
   describe("LingoProviderWrapper", () => {
     it("renders nothing while loading by default, then shows children", async () => {
-      const deferred = createDeferred<{ locale: string; files: Record<string, unknown> }>();
+      const deferred = createDeferred<{
+        locale: string;
+        files: Record<string, unknown>;
+      }>();
       const loadDictionary = vi.fn(() => deferred.promise);
 
       const Child = () => <div data-testid="child">ok</div>;
@@ -97,7 +100,9 @@ describe("client/provider", () => {
     it("propagates load errors to the nearest error boundary", async () => {
       const loadDictionary = vi.fn().mockRejectedValue(new Error("boom"));
       const onError = vi.fn();
-      const consoleSpy = vi.spyOn(console, "error").mockImplementation(() => {});
+      const consoleSpy = vi
+        .spyOn(console, "error")
+        .mockImplementation(() => {});
 
       render(
         <TestErrorBoundary onError={onError}>
@@ -110,7 +115,7 @@ describe("client/provider", () => {
       await waitFor(() => expect(onError).toHaveBeenCalled());
       expect(onError.mock.calls[0][0]).toBeInstanceOf(Error);
       expect(onError.mock.calls[0][0].message).toBe("boom");
-      
+
       const errorBoundary = await screen.findByTestId("boundary-error");
       expect(errorBoundary).not.toBeNull();
       expect(errorBoundary.textContent).toBe("error");

packages/spec/src/locales.spec.ts

@@ -1,6 +1,7 @@
 import { describe, it, expect } from "vitest";
 import {
   getLocaleCodeDelimiter,
+  localeCodeSchema,
   normalizeLocale,
   resolveLocaleCode,
   resolveOverriddenLocale,
@@ -88,3 +89,57 @@ describe("resolveOverridenLocale", () => {
     expect(resolveOverriddenLocale("frFR", "-")).toEqual("frFR");
   });
 });
+
+describe("localeCodeSchema validation", () => {
+  describe("standard BCP 47 format (hyphen)", () => {
+    it("should accept language-region codes", () => {
+      expect(localeCodeSchema.safeParse("en-US").success).toBe(true);
+      expect(localeCodeSchema.safeParse("fr-CA").success).toBe(true);
+      expect(localeCodeSchema.safeParse("es-MX").success).toBe(true);
+    });
+
+    it("should accept language-script-region codes", () => {
+      expect(localeCodeSchema.safeParse("zh-Hans-CN").success).toBe(true);
+      expect(localeCodeSchema.safeParse("sr-Latn-RS").success).toBe(true);
+      expect(localeCodeSchema.safeParse("sr-Cyrl-RS").success).toBe(true);
+    });
+  });
+
+  describe("underscore format (Java/Android)", () => {
+    it("should accept language_region codes", () => {
+      expect(localeCodeSchema.safeParse("en_US").success).toBe(true);
+      expect(localeCodeSchema.safeParse("pt_BR").success).toBe(true);
+      expect(localeCodeSchema.safeParse("de_DE").success).toBe(true);
+    });
+
+    it("should accept language_script_region codes", () => {
+      expect(localeCodeSchema.safeParse("zh_Hans_CN").success).toBe(true);
+      expect(localeCodeSchema.safeParse("sr_Cyrl_RS").success).toBe(true);
+    });
+  });
+
+  describe("Android r-prefix format", () => {
+    it("should accept language-rRegion codes", () => {
+      expect(localeCodeSchema.safeParse("en-rUS").success).toBe(true);
+      expect(localeCodeSchema.safeParse("fr-rCA").success).toBe(true);
+      expect(localeCodeSchema.safeParse("es-rMX").success).toBe(true);
+      expect(localeCodeSchema.safeParse("zh-rCN").success).toBe(true);
+    });
+  });
+
+  describe("invalid locale codes", () => {
+    it("should reject invalid language codes", () => {
+      expect(localeCodeSchema.safeParse("invalid-US").success).toBe(false);
+      expect(localeCodeSchema.safeParse("xx-US").success).toBe(false);
+    });
+
+    it("should reject invalid region codes", () => {
+      expect(localeCodeSchema.safeParse("en-FAKE").success).toBe(false);
+      expect(localeCodeSchema.safeParse("en-ZZ").success).toBe(false);
+    });
+
+    it("should reject invalid script codes", () => {
+      expect(localeCodeSchema.safeParse("zh-Fake-CN").success).toBe(false);
+    });
+  });
+});