diff --git a/composer.lock b/composer.lock
index 636f36e..6777d6d 100644
--- a/composer.lock
+++ b/composer.lock
@@ -1197,16 +1197,16 @@
         },
         {
             "name": "phpstan/phpstan",
-            "version": "1.10.55",
+            "version": "1.10.56",
             "source": {
                 "type": "git",
                 "url": "https://github.com/phpstan/phpstan.git",
-                "reference": "9a88f9d18ddf4cf54c922fbeac16c4cb164c5949"
+                "reference": "27816a01aea996191ee14d010f325434c0ee76fa"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/phpstan/phpstan/zipball/9a88f9d18ddf4cf54c922fbeac16c4cb164c5949",
-                "reference": "9a88f9d18ddf4cf54c922fbeac16c4cb164c5949",
+                "url": "https://api.github.com/repos/phpstan/phpstan/zipball/27816a01aea996191ee14d010f325434c0ee76fa",
+                "reference": "27816a01aea996191ee14d010f325434c0ee76fa",
                 "shasum": ""
             },
             "require": {
@@ -1255,7 +1255,7 @@
                     "type": "tidelift"
                 }
             ],
-            "time": "2024-01-08T12:32:40+00:00"
+            "time": "2024-01-15T10:43:00+00:00"
         },
         {
             "name": "phpunit/php-code-coverage",
@@ -1580,16 +1580,16 @@
         },
         {
             "name": "phpunit/phpunit",
-            "version": "10.5.5",
+            "version": "10.5.7",
             "source": {
                 "type": "git",
                 "url": "https://github.com/sebastianbergmann/phpunit.git",
-                "reference": "ed21115d505b4b4f7dc7b5651464e19a2c7f7856"
+                "reference": "e5c5b397a95cb0db013270a985726fcae93e61b8"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/sebastianbergmann/phpunit/zipball/ed21115d505b4b4f7dc7b5651464e19a2c7f7856",
-                "reference": "ed21115d505b4b4f7dc7b5651464e19a2c7f7856",
+                "url": "https://api.github.com/repos/sebastianbergmann/phpunit/zipball/e5c5b397a95cb0db013270a985726fcae93e61b8",
+                "reference": "e5c5b397a95cb0db013270a985726fcae93e61b8",
                 "shasum": ""
             },
             "require": {
@@ -1661,7 +1661,7 @@
             "support": {
                 "issues": "https://github.com/sebastianbergmann/phpunit/issues",
                 "security": "https://github.com/sebastianbergmann/phpunit/security/policy",
-                "source": "https://github.com/sebastianbergmann/phpunit/tree/10.5.5"
+                "source": "https://github.com/sebastianbergmann/phpunit/tree/10.5.7"
             },
             "funding": [
                 {
@@ -1677,7 +1677,7 @@
                     "type": "tidelift"
                 }
             ],
-            "time": "2023-12-27T15:13:52+00:00"
+            "time": "2024-01-14T16:40:30+00:00"
         },
         {
             "name": "psr/container",
diff --git a/tests/GuardTest.php b/tests/GuardTest.php
index ffa4087..7c3fbcf 100644
--- a/tests/GuardTest.php
+++ b/tests/GuardTest.php
@@ -4,6 +4,7 @@ namespace DNW\Skills\Tests;
 
 use DNW\Skills\Guard;
 use Exception;
+
 class GuardTest extends TestCase
 {
     public function testArgumentNotNull(): void
diff --git a/tests/RatingTest.php b/tests/RatingTest.php
new file mode 100644
index 0000000..df14472
--- /dev/null
+++ b/tests/RatingTest.php
@@ -0,0 +1,32 @@
+<?php
+
+namespace DNW\Skills\Tests;
+
+use DNW\Skills\Rating;
+
+class RatingTest extends TestCase
+{
+    public function testGetRatingParameters(): void
+    {
+        $rating = new Rating(100, 10, 5);
+        $this->assertEquals(100, $rating->getMean());
+        $this->assertEquals(10, $rating->getStandardDeviation());
+        $this->assertEquals(50, $rating->getConservativeRating());
+        $this->assertEquals("mean=100.0000, standardDeviation=10.0000", (string)$rating);
+    }
+
+    public function testPartialUpdate(): void
+    {
+        $rating = new Rating(100, 10, 5);
+        $rating_prior = new Rating(100, 10, 5);
+        $rating_new = new Rating(200, 10, 5);
+
+        $rating_partial = $rating ->getPartialUpdate($rating_prior, $rating_new, 0.5);
+
+
+        $this->assertEquals(150, $rating_partial->getMean());
+        $this->assertEquals(10, $rating_partial->getStandardDeviation());
+        $this->assertEquals(100, $rating_partial->getConservativeRating());
+        $this->assertEquals("mean=150.0000, standardDeviation=10.0000", (string)$rating_partial);
+    }
+}