test: increase ui test coverage

src/app/translation/i18n.spec.ts

@@ -0,0 +1,81 @@
+/*
+ * Copyright (C) 2022 StApps
+ *  This program is free software: you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License as published by the Free
+ *  Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful, but WITHOUT
+ *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ *  FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ *  more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with
+ *  this program. If not, see <https://www.gnu.org/licenses/>.
+ */
+
+/* eslint-disable @typescript-eslint/no-explicit-any,jsdoc/require-jsdoc,@typescript-eslint/no-non-null-assertion */
+import english from '../../assets/i18n/en.json';
+import german from '../../assets/i18n/de.json';
+
+const exceptions = new Set([
+  'login',
+  'ok',
+  'protein',
+  'feedback',
+  'name',
+  'status',
+  'issn',
+  'ejournal',
+  'backup',
+  'export',
+]);
+
+const languages = [
+  ['english', english],
+  ['german', german],
+] as [string, any][];
+
+describe('i18n', function () {
+  for (const [name, language] of languages) {
+    const [targetName, target] = languages.find(([target]) => target !== name)!;
+
+    describe(`${name} (compare to ${targetName})`, function () {
+      it('should have translations for all languages', function () {
+        traverseCompare(target, language, (a, b, path) => {
+          expect(typeof b).toBe(
+            typeof a,
+            `Missing translation for ${path.join('.')}`,
+          );
+        });
+      });
+
+      it('should have unique translations for each language', function () {
+        traverseCompare(target, language, (a, b, path) => {
+          if (!exceptions.has(a.toLowerCase())) {
+            expect(b).not.toBe(
+              a,
+              `Do not copy translations (${path.join(
+                '.',
+              )}). If this is a mistake, add an exception in 'src/app/translation/i18n.spec.ts'`,
+            );
+          }
+        });
+      });
+    });
+  }
+});
+
+function traverseCompare(
+  a: any,
+  b: any,
+  compare: (a: any, b: any, path: string[]) => void,
+  path: string[] = [],
+) {
+  for (const key of Object.keys(a)) {
+    if (typeof a[key] === 'object') {
+      traverseCompare(a[key], b[key], compare, [...path, key]);
+    } else {
+      compare(a[key], b[key], [...path, key]);
+    }
+  }
+}