Try Default Locale Rather than English

.github/workflows/main.yml

@@ -26,7 +26,7 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Install locales
-        run: sudo apt-get install -y language-pack-fr language-pack-de language-pack-en
+        run: sudo apt-get install -y language-pack-fr language-pack-de
 
       - name: Setup PHP, with composer and extensions
         uses: shivammathur/setup-php@v2

tests/PhpSpreadsheetTests/Shared/StringHelperLocaleTest.php

@@ -37,8 +37,8 @@ class StringHelperLocaleTest extends TestCase
         }
         $result = StringHelper::getCurrencyCode();
         self::assertSame('€', $result);
-        if (!setlocale(LC_ALL, 'en_ca', 'en_CA')) {
-            self::markTestSkipped('Unable to set en_ca locale for testing.');
+        if (!setlocale(LC_ALL, $this->currentLocale)) {
+            self::markTestSkipped('Unable to restore default locale.');
         }
         $result = StringHelper::getCurrencyCode();
         self::assertSame('€', $result, 'result persists despite locale change');