#3979 - Make an educated guess about how to set UF locale. Add test-case.

Civi/Core/Locale.php

@@ -203,6 +203,14 @@ class Locale {
       $validDbLocales = \Civi::settings()->get('languageLimit');
       $locale->db = static::pickFirstLocale(array_keys($validDbLocales), $fallbacks) ?: $systemDefault;
     }
+
+    // Determine locale for UF APIs: This next bit is a little bit wrong.
+    // We should have something like `$validUfLanguages` and pick the closest match.
+    // Or perhaps each `CRM_Utils_System_{$UF}` should have a `negotiate()` helper.
+    // But it's a academic... D7/D8/BD are the only UF's which implement `setUFLocale`/`getUFLocale`,
+    // and they drop the country-code - which basically addresses the goal (falling back to a more generic locale).
+    $locale->uf = $locale->ts;
+
     return $locale;
   }
 

tests/phpunit/E2E/Api4/LocaleTest.php

@@ -2,22 +2,78 @@
 
 namespace E2E\Api4;
 
+use Civi\API\Event\RespondEvent;
+
 /**
  * Class LocaleTest
+ *
  * @package E2E\Api4
  * @group e2e
  */
 class LocaleTest extends \CiviEndToEndTestCase {
 
+  public function getLanguageExamples(): array {
+    $results = [];
+    switch (CIVICRM_UF) {
+      case 'Drupal':
+      case 'Drupal8':
+      case 'Backdrop':
+        $results[] = ['de_DE', 'de_CH', 't', 'Yes', 'Ja'];
+        // That's weird -- you install Drupal's "de", and you do `setUFLocale('de_DE')`, and
+        // the result is... to report back as 'de_DE'. Weird. But the actual string is OK...
+        break;
+
+      case 'WordPress':
+        $results[] = ['de_DE', 'de_DE', '__', 'Yes', 'Ja'];
+        break;
+
+      case 'Joomla':
+      default:
+        $this->fail('Test not implemented for ' . CIVICRM_UF);
+    }
+    return $results;
+  }
+
   /**
-   * Ensure that
+   * APIv4 allows you to request that operations be processed in a specific language.
+   *
+   * @param string $civiLocale
+   *   The locale to specify in Civi. (eg Civi\Api4\Foo::bar()->setLanguage($civiLocale))
+   *   Ex: 'de_DE'
+   * @param string $expectUfLocale
+   *   The corresponding locale in the UF.
+   *   Ex: 'de'
+   * @param string|array $translator
+   *   The user-framework's translation method.
+   *   Ex: 't' (Drupal) or '__' (WordPress)
+   * @param string $inputString
+   *   The string to translate.
+   *   Ex: 'Yes', 'Login', 'Continue'
+   * @param string $expectString
+   *   The string that should be returned.
+   *   Ex: 'Ja', 'Anmeldung', 'Fortsetzen'
+   *
+   * @dataProvider getLanguageExamples
    */
-  public function testSetLanguage() {
+  public function testSetLanguage($civiLocale, $expectUfLocale, $translator, $inputString, $expectString) {
+    $actualStrings = [];
+    $actualLocales = [];
+    \Civi::dispatcher()->addListener('civi.api.respond', function (RespondEvent $e) use (&$actualStrings, &$actualLocales, $translator, $inputString, $civiLocale) {
+      $isTranslatedRequest = ($e->getApiRequest()->getLanguage() === $civiLocale);
+      if ($isTranslatedRequest) {
+        $actualLocales[] = \CRM_Utils_System::getUFLocale();
+        $actualStrings[] = call_user_func($translator, $inputString);
+      }
+    }, -100);
     $contacts = civicrm_api4('Contact', 'get', [
       'limit' => 25,
-      'language' => 'en_US',
+      'language' => $civiLocale,
     ]);
-    $this->assertTrue(count($contacts) > 0);
+    $this->assertTrue(count($contacts) > 0, 'The API call should return successfully.');
+    $this->assertEquals(1, count($actualLocales), 'We should observed one UF locale.');
+    $this->assertEquals(1, count($actualStrings), 'We should observed one UF translation.');
+    $this->assertEquals($expectUfLocale . ':' . $expectString, $actualLocales[0] . ':' . $actualStrings[0],
+      "Expected UF to report locale as '$expectUfLocale:$expectString'.");
   }
 
 }