refactor(tsukihime): swap Animetosho backend for TsukiHime API (#165)

src/tsukihime/lang.test.ts

@@ -0,0 +1,45 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+
+import {
+  tsukihimeLangToFilenameSuffix,
+  tsukihimeTrackMatchesLanguages,
+  describeTsukihimeTabLanguages,
+  normalizeTsukihimeLangCode,
+} from './lang.js';
+
+test('normalizeTsukihimeLangCode collapses 2/3-letter and region variants', () => {
+  assert.equal(normalizeTsukihimeLangCode('eng'), 'en');
+  assert.equal(normalizeTsukihimeLangCode('en'), 'en');
+  assert.equal(normalizeTsukihimeLangCode('en-US'), 'en');
+  assert.equal(normalizeTsukihimeLangCode('GER'), 'de');
+  assert.equal(normalizeTsukihimeLangCode('jpn'), 'ja');
+  assert.equal(normalizeTsukihimeLangCode('vie'), 'vie');
+  assert.equal(normalizeTsukihimeLangCode(''), '');
+});
+
+test('tsukihimeTrackMatchesLanguages matches across code forms', () => {
+  assert.equal(tsukihimeTrackMatchesLanguages('eng', ['en']), true);
+  assert.equal(tsukihimeTrackMatchesLanguages('eng', ['en', 'eng']), true);
+  assert.equal(tsukihimeTrackMatchesLanguages('ger', ['de']), true);
+  assert.equal(tsukihimeTrackMatchesLanguages('por', ['en']), false);
+  assert.equal(tsukihimeTrackMatchesLanguages('spa', ['en', 'de']), false);
+});
+
+test('tsukihimeTrackMatchesLanguages keeps unknown-language tracks visible', () => {
+  assert.equal(tsukihimeTrackMatchesLanguages('', ['en']), true);
+  assert.equal(tsukihimeTrackMatchesLanguages('und', ['en']), true);
+});
+
+test('describeTsukihimeTabLanguages names common languages and dedupes', () => {
+  assert.equal(describeTsukihimeTabLanguages(['en', 'eng']), 'English');
+  assert.equal(describeTsukihimeTabLanguages(['de']), 'German');
+  assert.equal(describeTsukihimeTabLanguages(['en', 'de']), 'English / German');
+  assert.equal(describeTsukihimeTabLanguages(['vie']), 'VIE');
+  assert.equal(describeTsukihimeTabLanguages([]), 'English');
+});
+
+test('tsukihimeLangToFilenameSuffix is re-exported from the pure module', () => {
+  assert.equal(tsukihimeLangToFilenameSuffix('jpn'), 'ja');
+  assert.equal(tsukihimeLangToFilenameSuffix('eng'), 'en');
+});