diff --git a/Utils/MbStringUtils.php b/Utils/MbStringUtils.php
index 9673ddf9a..008d3ffe6 100644
--- a/Utils/MbStringUtils.php
+++ b/Utils/MbStringUtils.php
@@ -283,44 +283,43 @@ final class MbStringUtils
     /**
      * Get the utf-8 boundary of a string
      *
-     * @param string $text   To search for utf-8 boundary
-     * @param int    $offset Search offset
+     * @param string $text   QP text to search for utf-8 boundary
+     * @param int    $length Last character boundary prior to this length
      *
      * @return int
      *
      * @since 1.0.0
      */
-    public static function utf8CharBoundary(string $text, int $offset = 0) : int
+    public static function utf8CharBoundary(string $text, int $length = 0) : int
     {
         $reset = 3;
-        $pos   = $offset;
 
         do {
-            $lastChunk  = \substr($text, $pos - $reset, $reset);
+            $lastChunk  = \substr($text, $length - $reset, $reset);
             $encodedPos = \strpos($lastChunk, '=');
 
             if ($encodedPos === false) {
                 break;
             }
 
-            $hex = \substr($text, $pos - $reset + $encodedPos + 1, 2);
+            $hex = \substr($text, $length - $reset + $encodedPos + 1, 2);
             $dec = \hexdec($hex);
 
             if ($dec < 128) {
                 if ($encodedPos > 0) {
-                    $pos -= $reset - $encodedPos;
+                    $length -= $reset - $encodedPos;
                 }
 
                 break;
             } elseif ($dec >= 192) {
-                $pos -= $reset - $encodedPos;
+                $length -= $reset - $encodedPos;
                 break;
-            } elseif ($dec < 192) {
+            } else { /* $dec < 192 */
                 $reset += 3;
             }
         } while (true);
 
-        return $pos;
+        return $length;
     }
 
     /**
diff --git a/tests/Algorithm/Maze/MazeGeneratorTest.php b/tests/Algorithm/Maze/MazeGeneratorTest.php
index 5bf5e3093..e3724d90d 100644
--- a/tests/Algorithm/Maze/MazeGeneratorTest.php
+++ b/tests/Algorithm/Maze/MazeGeneratorTest.php
@@ -12,7 +12,7 @@
  */
 declare(strict_types=1);
 
-namespace phpOMS\tests\Algorithm\PathFinding;
+namespace phpOMS\tests\Algorithm\Maze;
 
 use phpOMS\Algorithm\Maze\MazeGenerator;
 
diff --git a/tests/Localization/L11nManagerTest.php b/tests/Localization/L11nManagerTest.php
index b5665f6e8..7296743b8 100644
--- a/tests/Localization/L11nManagerTest.php
+++ b/tests/Localization/L11nManagerTest.php
@@ -140,8 +140,12 @@ class L11nManagerTest extends \PHPUnit\Framework\TestCase
         self::assertEquals('USD 1.235', $this->l11nManager->getCurrency($l11n, 1.2345, 'long'));
 
         $this->l11nManager->loadLanguage('en', '0', ['0' => ['CurrencyK' => 'K']]);
+        $this->l11nManager->loadLanguage('en', '0', ['0' => ['CurrencyM' => 'M']]);
+        $this->l11nManager->loadLanguage('en', '0', ['0' => ['CurrencyB' => 'B']]);
         self::assertEquals('K$ 12.345', $this->l11nManager->getCurrency($l11n, 12345.0, 'long', '$', 1000));
         self::assertEquals('KUSD 12.345', $this->l11nManager->getCurrency($l11n, 12345.0, 'long', null, 1000));
+        self::assertEquals('M$ 123.5', $this->l11nManager->getCurrency($l11n, 123456789.0, 'short', '$', 1000000));
+        self::assertEquals('B$ 1.2', $this->l11nManager->getCurrency($l11n, 1234567890.0, 'short', '$', 1000000000));
     }
 
     /**
diff --git a/tests/Math/Topology/Metrics2DTest.php b/tests/Math/Topology/Metrics2DTest.php
index a121956f5..589f1e0dc 100644
--- a/tests/Math/Topology/Metrics2DTest.php
+++ b/tests/Math/Topology/Metrics2DTest.php
@@ -12,7 +12,7 @@
  */
 declare(strict_types=1);
 
-namespace phpOMS\tests\Math\Number;
+namespace phpOMS\tests\Math\Topology;
 
 use phpOMS\Math\Topology\Metrics2D;
 
diff --git a/tests/Math/Topology/MetricsNDTest.php b/tests/Math/Topology/MetricsNDTest.php
index 91e3a47e6..cafe5ebb1 100644
--- a/tests/Math/Topology/MetricsNDTest.php
+++ b/tests/Math/Topology/MetricsNDTest.php
@@ -12,7 +12,7 @@
  */
 declare(strict_types=1);
 
-namespace phpOMS\tests\Math\Number;
+namespace phpOMS\tests\Math\Topology;
 
 use phpOMS\Math\Topology\Metrics2D;
 use phpOMS\Math\Topology\MetricsND;
diff --git a/tests/Utils/ArrayUtilsTest.php b/tests/Utils/ArrayUtilsTest.php
index 281b3e0c5..61e5e54fb 100644
--- a/tests/Utils/ArrayUtilsTest.php
+++ b/tests/Utils/ArrayUtilsTest.php
@@ -61,6 +61,32 @@ class ArrayUtilsTest extends \PHPUnit\Framework\TestCase
         self::assertEquals('ab0', ArrayUtils::getArray('a/ab/1', $expected));
     }
 
+    /**
+     * @testdox A invalid array path returns null
+     * @covers phpOMS\Utils\ArrayUtils
+     * @group framework
+     */
+    public function testArrayInvalidArrayPath() : void
+    {
+        $expected = [
+            'a' => [
+                'aa' => 1,
+                'ab' => [
+                    'aba',
+                    'ab0',
+                    [
+                        3,
+                        'c',
+                    ],
+                    4,
+                ],
+            ],
+            2 => '2a',
+        ];
+
+        self::assertEquals(null, ArrayUtils::getArray('a/zzz/1', $expected));
+    }
+
     /**
      * @testdox Test recursively if a value is in an array
      * @covers phpOMS\Utils\ArrayUtils
@@ -106,6 +132,27 @@ class ArrayUtilsTest extends \PHPUnit\Framework\TestCase
         self::assertFalse(ArrayUtils::inArrayRecursive('aba', ArrayUtils::unsetArray('a/ab', $expected, '/')));
     }
 
+    /**
+     * @testdox Deleting an invalid array path returns the original array
+     * @covers phpOMS\Utils\ArrayUtils
+     * @group framework
+     */
+    public function testInvalidArrayDelete() : void
+    {
+        $expected = [
+            'a' => [
+                'aa' => 1,
+                'ab' => [
+                    'aba',
+                    'ab0',
+                ],
+            ],
+            2 => '2a',
+        ];
+
+        self::assertEquals($expected, ArrayUtils::unsetArray('a/zzz', $expected, '/'));
+    }
+
     /**
      * @testdox The recursive sum of all values in an array can be calculated
      * @covers phpOMS\Utils\ArrayUtils
diff --git a/tests/Utils/MbStringUtilsTest.php b/tests/Utils/MbStringUtilsTest.php
index 71f9e6952..a56cafcde 100644
--- a/tests/Utils/MbStringUtilsTest.php
+++ b/tests/Utils/MbStringUtilsTest.php
@@ -19,7 +19,7 @@ use phpOMS\Utils\MbStringUtils;
 require_once __DIR__ . '/../Autoloader.php';
 
 /**
- * @testdox phpOMS\tests\Utils\MbStringUtilsTest: String utilities
+ * @testdox phpOMS\tests\Utils\MbStringUtilsTest: Multi-Byte string utilities
  *
  * @internal
  */
@@ -152,8 +152,13 @@ class MbStringUtilsTest extends \PHPUnit\Framework\TestCase
         self::assertEquals(5, MbStringUtils::mb_count_chars('αααααΕεΙιΜμΨψ')['α']);
     }
 
+    /**
+     * @testdox The previous boundary of a utf-8 encoded quoted printable is identified correctly
+     * @covers phpOMS\Utils\MbStringUtils
+     * @group framework
+     */
     public function testUtf8CharBoundary() : void
     {
-        self::markTestIncomplete();
+        self::assertEquals(10, MbStringUtils::utf8CharBoundary('H=E4tten H=FCte ein =DF im Namen, w=E4ren sie m=F6glicherweise k', 12));
     }
 }
diff --git a/tests/Utils/StringUtilsTest.php b/tests/Utils/StringUtilsTest.php
index e8f0e782a..38ee52f92 100644
--- a/tests/Utils/StringUtilsTest.php
+++ b/tests/Utils/StringUtilsTest.php
@@ -166,6 +166,16 @@ class StringUtilsTest extends \PHPUnit\Framework\TestCase
         }));
     }
 
+    /**
+     * @testdox Stringify/rendering a unknown data type returns null
+     * @covers phpOMS\Utils\StringUtils
+     * @group framework
+     */
+    public function testInvalidStringify() : void
+    {
+        self::assertEquals(null, StringUtils::stringify(new class() {}));
+    }
+
     /**
      * @testdox The difference between two strings can be evaluated
      * @covers phpOMS\Utils\StringUtils