Add array for ISO639-2b language codes

tests/MDLanguagesSetTest.php

@@ -0,0 +1,38 @@
+<?PHP
+/**
+ * This script contains tests for the home page.
+ *
+ * @author Joshua Ramon Enslin <joshua@museum-digital.de>
+ */
+declare(strict_types = 1);
+use PHPUnit\Framework\TestCase;
+
+require __DIR__ . '/../src/MDLanguagesSet.php';
+
+/**
+ * Tests for home page.
+ */
+final class MDLanguagesSetTest extends TestCase {
+    /**
+     * Test to check whether the HTML page is correctly generated.
+     *
+     * @author Joshua Ramon Enslin <joshua@museum-digital.de>
+     * @group  ValidOutput
+     *
+     * @return void
+     */
+    public function testIso639ListIsCorrect():void {
+
+        foreach (MDLanguagesSet::AVAILABLE_LANGUAGES as $language_code => $language_name) {
+
+            self::assertArrayHasKey($language_code, MDLanguagesSet::LANGUAGES_ISO639_2B, 'Language ' . $language_code . ' (' . $language_name . ') has no entry in ISO639-2b language code list');
+            self::assertEquals(3, strlen(MDLanguagesSet::LANGUAGES_ISO639_2B[$language_code]), 'ISO639-2b entry for language ' . $language_code . ' (' . $language_name . ') is not = 3');
+
+        }
+
+        foreach (MDLanguagesSet::LANGUAGES_ISO639_2B as $language_code => $language_name) {
+            self::assertArrayHasKey($language_code, MDLanguagesSet::AVAILABLE_LANGUAGES, 'Language ' . $language_code . ' (' . $language_name . ') has an entry in ISO639-2b language code list, but not in the main list.');
+        }
+
+    }
+}