diff --git a/core/tests/Drupal/Tests/Component/Transliteration/PhpTransliterationTest.php b/core/tests/Drupal/Tests/Component/Transliteration/PhpTransliterationTest.php
index 965ede5..80a9ebb 100644
--- a/core/tests/Drupal/Tests/Component/Transliteration/PhpTransliterationTest.php
+++ b/core/tests/Drupal/Tests/Component/Transliteration/PhpTransliterationTest.php
@@ -33,14 +33,20 @@ public static function getInfo() {
    *   The original string.
    * @param string $expected
    *   The expected return from PHPTransliteration::transliterate().
+   * @param string $unknown_character
+   *   (optional) The character to substitute for characters in $string without
+   *   transliterated equivalents. Defaults to '?'.
+   * @param int $max_length
+   *   (optional) If provided, return at most this many characters, ensuring
+   *   that the transliteration does not split in the middle of an input
+   *   character's transliteration.
    *
    * @dataProvider providerTestPHPTransliteration
    */
-  public function testPHPTransliteration($langcode, $original, $expected) {
-    $printable = (isset($case[3])) ? $case[3] : $original;
+  public function testPHPTransliteration($langcode, $original, $expected, $unknown_character = '?', $max_length = NULL) {
     $transliterator_class = new PHPTransliteration();
-    $actual = $transliterator_class->transliterate($original, $langcode);
-    $this->assertSame($actual, $expected, sprintf('%s transliteration to %s is identical to %s for language %s in new class instance.', $printable, $actual, $expected, $langcode));
+    $actual = $transliterator_class->transliterate($original, $langcode, $unknown_character, $max_length);
+    $this->assertSame($expected, $actual);
   }
 
   /**
@@ -66,8 +72,6 @@ public static function providerTestPHPTransliteration() {
     // http://en.wikipedia.org/wiki/Gothic_alphabet
     // They are not in our tables, but should at least give us '?' (unknown).
     $five_byte = html_entity_decode('𐌰𐌸', ENT_NOQUOTES, 'UTF-8');
-    // Five-byte characters do not work in MySQL, so make a printable version.
-    $five_byte_printable = '𐌰𐌸';
 
     return array(
       // Each test case is (language code, input, output).
@@ -82,7 +86,7 @@ public static function providerTestPHPTransliteration() {
       array('fr', $three_byte, 'c'),
       array('fr', $four_byte, 'wii'),
       // Test 5-byte characters.
-      array('en', $five_byte, '??', $five_byte_printable),
+      array('en', $five_byte, '??'),
       // Test a language with no overrides.
       array('en', $two_byte, 'A O U A O aouaohello'),
       // Test language overrides provided by core.
@@ -101,6 +105,8 @@ public static function providerTestPHPTransliteration() {
       array('tr', 'Abayı serdiler bize. Söyleyeceğim yüzlerine. Sanırım hepimiz aynı şeyi düşünüyoruz.', 'Abayi serdiler bize. Soyleyecegim yuzlerine. Sanirim hepimiz ayni seyi dusunuyoruz.'),
       // Illegal/unknown unicode.
       array('en', chr(0xF8) . chr(0x80) . chr(0x80) . chr(0x80) . chr(0x80), '?'),
+      // Max length.
+      array('de', $two_byte, 'Ae Oe', '?', 5),
     );
   }