diff --git a/Math/Stochastic/Distribution/FDistribution.php b/Math/Stochastic/Distribution/FDistribution.php
index 25f55847c..6fa6852e6 100644
--- a/Math/Stochastic/Distribution/FDistribution.php
+++ b/Math/Stochastic/Distribution/FDistribution.php
@@ -53,6 +53,10 @@ final class FDistribution
      */
     public static function getMode(int $d1, int $d2) : float
     {
+        if ($d1 === 0) {
+            return 0.0;
+        }
+
         return ($d1 - 2) / $d1 * $d2 / ($d2 + 2);
     }
 
diff --git a/System/File/FileUtils.php b/System/File/FileUtils.php
index 49296ebd8..c17ac0a9c 100644
--- a/System/File/FileUtils.php
+++ b/System/File/FileUtils.php
@@ -98,30 +98,30 @@ final class FileUtils
      */
     public static function absolute(string $origPath) : string
     {
-        if (!\file_exists($origPath) || \realpath($origPath) === false) {
-            $startsWithSlash = \strpos($origPath, '/') === 0 ? '/' : '';
-
-            $path  = [];
-            $parts = \explode('/', $origPath);
-
-            foreach ($parts as $part) {
-                if (empty($part) || $part === '.') {
-                    continue;
-                }
-
-                if ($part !== '..') {
-                    $path[] = $part;
-                } elseif (!empty($path)) {
-                    \array_pop($path);
-                } else {
-                    throw new PathException($origPath);
-                }
-            }
-
-            return $startsWithSlash . \implode('/', $path);
+        if (\file_exists($origPath) || \realpath($origPath) !== false) {
+            return \realpath($origPath);
         }
 
-        return \realpath($origPath);
+        $startsWithSlash = \strpos($origPath, '/') === 0 ? '/' : '';
+
+        $path  = [];
+        $parts = \explode('/', $origPath);
+
+        foreach ($parts as $part) {
+            if (empty($part) || $part === '.') {
+                continue;
+            }
+
+            if ($part !== '..') {
+                $path[] = $part;
+            } elseif (!empty($path)) {
+                \array_pop($path);
+            } else {
+                throw new PathException($origPath);
+            }
+        }
+
+        return $startsWithSlash . \implode('/', $path);
     }
 
     /**
diff --git a/tests/Account/AccountTest.php b/tests/Account/AccountTest.php
index 1c54b31ca..c3ccca6bd 100644
--- a/tests/Account/AccountTest.php
+++ b/tests/Account/AccountTest.php
@@ -221,6 +221,12 @@ class AccountTest extends \PHPUnit\Framework\TestCase
             new class() extends PermissionAbstract {},
         ]);
         self::assertCount(4, $account->getPermissions());
+
+        $account->addPermissions([[
+            new class() extends PermissionAbstract {},
+            new class() extends PermissionAbstract {},
+        ]]);
+        self::assertCount(6, $account->getPermissions());
     }
 
     /**
diff --git a/tests/Account/GroupTest.php b/tests/Account/GroupTest.php
index a24b8115a..f2a5c4607 100644
--- a/tests/Account/GroupTest.php
+++ b/tests/Account/GroupTest.php
@@ -100,22 +100,28 @@ class GroupTest extends \PHPUnit\Framework\TestCase
      */
     public function testPermissionAdd() : void
     {
-        $account = new Group();
+        $group = new Group();
 
-        $account->addPermission(new class() extends PermissionAbstract {});
-        self::assertCount(1, $account->getPermissions());
+        $group->addPermission(new class() extends PermissionAbstract {});
+        self::assertCount(1, $group->getPermissions());
 
-        $account->setPermissions([
+        $group->setPermissions([
             new class() extends PermissionAbstract {},
             new class() extends PermissionAbstract {},
         ]);
-        self::assertCount(2, $account->getPermissions());
+        self::assertCount(2, $group->getPermissions());
 
-        $account->addPermissions([
+        $group->addPermissions([
             new class() extends PermissionAbstract {},
             new class() extends PermissionAbstract {},
         ]);
-        self::assertCount(4, $account->getPermissions());
+        self::assertCount(4, $group->getPermissions());
+
+        $group->addPermissions([[
+            new class() extends PermissionAbstract {},
+            new class() extends PermissionAbstract {},
+        ]]);
+        self::assertCount(6, $group->getPermissions());
     }
 
     /**
@@ -125,13 +131,13 @@ class GroupTest extends \PHPUnit\Framework\TestCase
      */
     public function testPermissionExists() : void
     {
-        $account = new Group();
+        $group = new Group();
 
-        $account->addPermission(new class() extends PermissionAbstract {});
-        self::assertCount(1, $account->getPermissions());
+        $group->addPermission(new class() extends PermissionAbstract {});
+        self::assertCount(1, $group->getPermissions());
 
-        self::assertFalse($account->hasPermission(PermissionType::READ, 1, 'a', 'a', 1, 1, 1));
-        self::assertTrue($account->hasPermission(PermissionType::NONE));
+        self::assertFalse($group->hasPermission(PermissionType::READ, 1, 'a', 'a', 1, 1, 1));
+        self::assertTrue($group->hasPermission(PermissionType::NONE));
     }
 
     /**
@@ -141,16 +147,16 @@ class GroupTest extends \PHPUnit\Framework\TestCase
      */
     public function testPermissionRemove() : void
     {
-        $account = new Group();
+        $group = new Group();
 
         $perm = new class() extends PermissionAbstract {};
         $perm->setPermission(PermissionType::READ);
 
-        $account->addPermission($perm);
-        self::assertCount(1, $account->getPermissions());
+        $group->addPermission($perm);
+        self::assertCount(1, $group->getPermissions());
 
-        $account->removePermission($perm);
-        self::assertCount(0, $account->getPermissions());
+        $group->removePermission($perm);
+        self::assertCount(0, $group->getPermissions());
     }
 
     /**
diff --git a/tests/Ai/Ocr/BasicOcrTest.php b/tests/Ai/Ocr/BasicOcrTest.php
new file mode 100644
index 000000000..6ea8367ff
--- /dev/null
+++ b/tests/Ai/Ocr/BasicOcrTest.php
@@ -0,0 +1,26 @@
+<?php
+/**
+ * Orange Management
+ *
+ * PHP Version 7.4
+ *
+ * @package   tests
+ * @copyright Dennis Eichhorn
+ * @license   OMS License 1.0
+ * @version   1.0.0
+ * @link      https://orange-management.org
+ */
+declare(strict_types=1);
+
+namespace phpOMS\tests\Ai\Ocr;
+
+/**
+ * @internal
+ */
+class BasicOcrTest extends \PHPUnit\Framework\TestCase
+{
+    public function testPlaceholder() : void
+    {
+        self::markTestIncomplete();
+    }
+}
diff --git a/tests/Business/Marketing/CustomerValueTest.php b/tests/Business/Marketing/CustomerValueTest.php
new file mode 100644
index 000000000..2d0fd2461
--- /dev/null
+++ b/tests/Business/Marketing/CustomerValueTest.php
@@ -0,0 +1,41 @@
+<?php
+/**
+ * Orange Management
+ *
+ * PHP Version 7.4
+ *
+ * @package   tests
+ * @copyright Dennis Eichhorn
+ * @license   OMS License 1.0
+ * @version   1.0.0
+ * @link      https://orange-management.org
+ */
+declare(strict_types=1);
+
+namespace phpOMS\tests\Business\Marketing;
+
+use phpOMS\Business\Marketing\Metrics;
+
+/**
+ * @testdox phpOMS\tests\Business\Marketing\CustomerValueTest: Customer value
+ *
+ * @internal
+ */
+class CustomerValueTest extends \PHPUnit\Framework\TestCase
+{
+    /**
+     * @group framework
+     */
+    public function testSimpleCLV() : void
+    {
+        self::markTestIncomplete();
+    }
+
+    /**
+     * @group framework
+     */
+    public function testMRR() : void
+    {
+        self::markTestIncomplete();
+    }
+}
diff --git a/tests/Business/Marketing/MetricsTest.php b/tests/Business/Marketing/MetricsTest.php
index 52ba9567b..fc8830ca2 100644
--- a/tests/Business/Marketing/MetricsTest.php
+++ b/tests/Business/Marketing/MetricsTest.php
@@ -31,4 +31,44 @@ class MetricsTest extends \PHPUnit\Framework\TestCase
     {
         self::assertEqualsWithDelta(0.85, Metrics::getCustomerRetention(105, 20, 100), 0.01);
     }
+
+    /**
+     * @group framework
+     */
+    public function testBerrysCustomerProfits() : void
+    {
+        self::markTestIncomplete();
+    }
+
+    /**
+     * @group framework
+     */
+    public function testLifeTimeValue() : void
+    {
+        self::markTestIncomplete();
+    }
+
+    /**
+     * @group framework
+     */
+    public function testSimpleRetentionLifeTimeValue() : void
+    {
+        self::markTestIncomplete();
+    }
+
+    /**
+     * @group framework
+     */
+    public function testMailingSuccess() : void
+    {
+        self::markTestIncomplete();
+    }
+
+    /**
+     * @group framework
+     */
+    public function testMigrationModel() : void
+    {
+        self::markTestIncomplete();
+    }
 }
diff --git a/tests/Math/Functions/BetaTest.php b/tests/Math/Functions/BetaTest.php
new file mode 100644
index 000000000..546f5e1a0
--- /dev/null
+++ b/tests/Math/Functions/BetaTest.php
@@ -0,0 +1,40 @@
+<?php
+/**
+ * Orange Management
+ *
+ * PHP Version 7.4
+ *
+ * @package   tests
+ * @copyright Dennis Eichhorn
+ * @license   OMS License 1.0
+ * @version   1.0.0
+ * @link      https://orange-management.org
+ */
+declare(strict_types=1);
+
+namespace phpOMS\tests\Math\Functions;
+
+use phpOMS\Math\Functions\Beta;
+
+/**
+ * @testdox phpOMS\tests\Math\Functions\BetaTest: Beta function
+ *
+ * @internal
+ */
+class BetaTest extends \PHPUnit\Framework\TestCase
+{
+    public function testIncompleteBeta() : void
+    {
+        self::markTestIncomplete();
+    }
+
+    public function testLogBeta() : void
+    {
+        self::markTestIncomplete();
+    }
+
+    public function beta() : void
+    {
+        self::markTestIncomplete();
+    }
+}
diff --git a/tests/Math/Functions/FunctionsTest.php b/tests/Math/Functions/FunctionsTest.php
index cd89f8eb6..bd9b0bc53 100644
--- a/tests/Math/Functions/FunctionsTest.php
+++ b/tests/Math/Functions/FunctionsTest.php
@@ -108,4 +108,14 @@ class FunctionsTest extends \PHPUnit\Framework\TestCase
         self::assertEquals(5, Functions::getRelativeDegree(12, 12, 7));
         self::assertEquals(11, Functions::getRelativeDegree(6, 12, 7));
     }
+
+    public function testErf() : void
+    {
+        self::markTestIncomplete();
+    }
+
+    public function testErfc() : void
+    {
+        self::markTestIncomplete();
+    }
 }
diff --git a/tests/Math/Functions/GammaTest.php b/tests/Math/Functions/GammaTest.php
index dcf52a57f..dbc213c54 100644
--- a/tests/Math/Functions/GammaTest.php
+++ b/tests/Math/Functions/GammaTest.php
@@ -93,4 +93,9 @@ class GammaTest extends \PHPUnit\Framework\TestCase
 
         self::assertTrue(true);
     }
+
+    public function testLogGamma() : void
+    {
+        self::markTestIncomplete();
+    }
 }
diff --git a/tests/Math/Stochastic/Distribution/FDistributionTest.php b/tests/Math/Stochastic/Distribution/FDistributionTest.php
index 05b8b2a2a..7c4bc7a9e 100644
--- a/tests/Math/Stochastic/Distribution/FDistributionTest.php
+++ b/tests/Math/Stochastic/Distribution/FDistributionTest.php
@@ -14,13 +14,43 @@ declare(strict_types=1);
 
 namespace phpOMS\tests\Math\Stochastic\Distribution;
 
+use phpOMS\Math\Stochastic\Distribution\FDistribution;
+
 /**
  * @internal
  */
 class FDistributionTest extends \PHPUnit\Framework\TestCase
 {
-    public function testPlaceholder() : void
+    public function testMean() : void
     {
-        self::markTestIncomplete();
+        self::assertEquals(0.0, FDistribution::getMean(2));
+        self::assertEquals(2, FDistribution::getMean(4));
+    }
+
+    public function testMode() : void
+    {
+        self::assertEquals(0.0, FDistribution::getMode(0, 0));
+        self::assertEqualsWithDelta(0.0, FDistribution::getMode(2, 3), 0.01);
+        self::assertEqualsWithDelta(1 / 3 * 2 / 3, FDistribution::getMode(3, 4), 0.01);
+    }
+
+    public function testVariance() : void
+    {
+        self::assertEquals(0.0, FDistribution::getVariance(1, 2));
+        self::assertEquals(0.0, FDistribution::getVariance(1, 4));
+        self::assertEqualsWithDelta(11.1111, FDistribution::getVariance(3, 5), 0.01);
+    }
+
+    public function testStandardDeviation() : void
+    {
+        self::assertEquals(0.0, FDistribution::getStandardDeviation(1, 2));
+        self::assertEquals(0.0, FDistribution::getStandardDeviation(1, 4));
+        self::assertEqualsWithDelta(\sqrt(11.1111), FDistribution::getStandardDeviation(3, 5), 0.01);
+    }
+
+    public function testSkewness() : void
+    {
+        self::assertEquals(0.0, FDistribution::getSkewness(1, 6));
+        self::assertEquals(2 * (2 * 4 + 7 - 2) / (7 - 6) * \sqrt(2 * (7 - 4) / (4 * (7 + 4 - 2))), FDistribution::getSkewness(4, 7));
     }
 }
diff --git a/tests/Math/Stochastic/Distribution/LogDistributionTest.php b/tests/Math/Stochastic/Distribution/LogDistributionTest.php
index 821515cb1..4604008f7 100644
--- a/tests/Math/Stochastic/Distribution/LogDistributionTest.php
+++ b/tests/Math/Stochastic/Distribution/LogDistributionTest.php
@@ -19,7 +19,32 @@ namespace phpOMS\tests\Math\Stochastic\Distribution;
  */
 class LogDistributionTest extends \PHPUnit\Framework\TestCase
 {
-    public function testPlaceholder() : void
+    public function testPmf() : void
+    {
+        self::markTestIncomplete();
+    }
+
+    public function testMean() : void
+    {
+        self::markTestIncomplete();
+    }
+
+    public function testMode() : void
+    {
+        self::markTestIncomplete();
+    }
+
+    public function testVariance() : void
+    {
+        self::markTestIncomplete();
+    }
+
+    public function testStandardDeviation() : void
+    {
+        self::markTestIncomplete();
+    }
+
+    public function testMgf() : void
     {
         self::markTestIncomplete();
     }
diff --git a/tests/Math/Stochastic/Distribution/LogisticDistributionTest.php b/tests/Math/Stochastic/Distribution/LogisticDistributionTest.php
index 59a17f225..287737811 100644
--- a/tests/Math/Stochastic/Distribution/LogisticDistributionTest.php
+++ b/tests/Math/Stochastic/Distribution/LogisticDistributionTest.php
@@ -19,7 +19,52 @@ namespace phpOMS\tests\Math\Stochastic\Distribution;
  */
 class LogisticDistributionTest extends \PHPUnit\Framework\TestCase
 {
-    public function testPlaceholder() : void
+    public function testPdf() : void
+    {
+        self::markTestIncomplete();
+    }
+
+    public function testCdf() : void
+    {
+        self::markTestIncomplete();
+    }
+
+    public function testMode() : void
+    {
+        self::markTestIncomplete();
+    }
+
+    public function testMean() : void
+    {
+        self::markTestIncomplete();
+    }
+
+    public function testMedian() : void
+    {
+        self::markTestIncomplete();
+    }
+
+    public function testVariance() : void
+    {
+        self::markTestIncomplete();
+    }
+
+    public function testStandardDeviation() : void
+    {
+        self::markTestIncomplete();
+    }
+
+    public function testSkewness() : void
+    {
+        self::markTestIncomplete();
+    }
+
+    public function testExKurtosis() : void
+    {
+        self::markTestIncomplete();
+    }
+
+    public function testEntropy() : void
     {
         self::markTestIncomplete();
     }
diff --git a/tests/Math/Stochastic/Distribution/ZTestTest.php b/tests/Math/Stochastic/Distribution/ZTestTest.php
index a6bcf5ac5..4ebd73eef 100644
--- a/tests/Math/Stochastic/Distribution/ZTestTest.php
+++ b/tests/Math/Stochastic/Distribution/ZTestTest.php
@@ -36,7 +36,7 @@ class ZTestTest extends \PHPUnit\Framework\TestCase
     public function testZTest() : void
     {
         //self::assertEqualsWithDelta(0.090574, ZTest::zTest(4, [3, 6, 7, 8, 6, 5, 4, 2, 1, 9]), 0.001);
-
+        self::markTestIncomplete();
         self::assertTrue(true);
     }
 }
diff --git a/tests/Message/Http/RestTest.php b/tests/Message/Http/RestTest.php
index 3b81c7d8c..18fb13d3e 100644
--- a/tests/Message/Http/RestTest.php
+++ b/tests/Message/Http/RestTest.php
@@ -93,4 +93,14 @@ class RestTest extends \PHPUnit\Framework\TestCase
         self::assertTrue($request->setData('gdata', 'abc'));
         self::assertEquals('abc', REST::request($request)->getJsonData()['args']['gdata']);
     }
+
+    public function testJsonRequest() : void
+    {
+        self::markTestIncomplete();
+    }
+
+    public function testMultiRequest() : void
+    {
+        self::markTestIncomplete();
+    }
 }
diff --git a/tests/Router/WebRouterTest.php b/tests/Router/WebRouterTest.php
index 4be07fe71..266c12b47 100644
--- a/tests/Router/WebRouterTest.php
+++ b/tests/Router/WebRouterTest.php
@@ -295,4 +295,14 @@ class WebRouterTest extends \PHPUnit\Framework\TestCase
             )
         );
     }
+
+    public function testDataValidation() : void
+    {
+        self::markTestIncomplete();
+    }
+
+    public function testDataFromPattern() : void
+    {
+        self::markTestIncomplete();
+    }
 }
diff --git a/tests/System/File/FileUtilsTest.php b/tests/System/File/FileUtilsTest.php
index f0b2db0c9..d7aa74a89 100644
--- a/tests/System/File/FileUtilsTest.php
+++ b/tests/System/File/FileUtilsTest.php
@@ -54,6 +54,7 @@ class FileUtilsTest extends \PHPUnit\Framework\TestCase
      */
     public function testAbsolute() : void
     {
+        self::assertEquals(\realpath(__DIR__ . '/..'), FileUtils::absolute(__DIR__ . '/..'));
         self::assertEquals('/test/ative', FileUtils::absolute('/test/path/for/../rel/../../ative'));
     }
 
@@ -66,4 +67,9 @@ class FileUtilsTest extends \PHPUnit\Framework\TestCase
     {
         self::assertEquals(0742, FileUtils::permissionToOctal('rwxr---w-'));
     }
+
+    public function testChangeFileEncoding() : void
+    {
+        self::markTestIncomplete();
+    }
 }
diff --git a/tests/Utils/MbStringUtilsTest.php b/tests/Utils/MbStringUtilsTest.php
index 273734369..71f9e6952 100644
--- a/tests/Utils/MbStringUtilsTest.php
+++ b/tests/Utils/MbStringUtilsTest.php
@@ -27,7 +27,7 @@ class MbStringUtilsTest extends \PHPUnit\Framework\TestCase
 {
     /**
      * @testdox The entropy of a string can be calculated
-     * @covers phpOMS\Utils\StringUtils
+     * @covers phpOMS\Utils\MbStringUtils
      * @group framework
      */
     public function testEntropy() : void
@@ -37,7 +37,7 @@ class MbStringUtilsTest extends \PHPUnit\Framework\TestCase
 
     /**
      * @testdox A string can be checked for multi-byte characters
-     * @covers phpOMS\Utils\StringUtils
+     * @covers phpOMS\Utils\MbStringUtils
      * @group framework
      */
     public function testHasMultiBytes() : void
@@ -151,4 +151,9 @@ class MbStringUtilsTest extends \PHPUnit\Framework\TestCase
     {
         self::assertEquals(5, MbStringUtils::mb_count_chars('αααααΕεΙιΜμΨψ')['α']);
     }
+
+    public function testUtf8CharBoundary() : void
+    {
+        self::markTestIncomplete();
+    }
 }