diff --git a/tests/_support/Helper/ValidNaturallyColorValuesProvider.php b/tests/_support/Helper/ValidNaturallyColorValuesProvider.php
new file mode 100644
index 0000000..8fc9bb6
--- /dev/null
+++ b/tests/_support/Helper/ValidNaturallyColorValuesProvider.php
@@ -0,0 +1,128 @@
+<?php
+
+
+namespace TorstenHettstedt\Colors\Tests\Helper;
+
+
+class ValidNaturallyColorValuesProvider
+{
+
+    const CMYK = 'cmyk';
+    const RGB  = 'rgb';
+    const HSV  = 'hsv';
+
+    /**
+     * @var array<string, array<string, float>[]>
+     */
+    protected array $definitions = [
+        'weiß'    => [
+            self::CMYK => [
+                'cyan'    => 0,
+                'magenta' => 0,
+                'yellow'  => 0,
+                'key'     => 0,
+            ],
+            self::RGB  => [
+                'red'   => 0xFF,
+                'green' => 0xFF,
+                'blue'  => 0xFF,
+            ],
+            self::HSV  => [
+                'hue'        =>   0,
+                'saturation' =>   0,
+                'value'      => 100,
+            ],
+        ],
+        'hellgrau' => [
+            self::CMYK => [
+                'cyan'    =>  0,
+                'magenta' =>  0,
+                'yellow'  =>  0,
+                'key'     => 67,
+            ],
+            self::RGB  => [
+                'red'   => 0x55,
+                'green' => 0x55,
+                'blue'  => 0x55,
+            ],
+            self::HSV  => [
+                'hue'        =>  0,
+                'saturation' =>  0,
+                'value'      => 33,
+            ],
+        ],
+        'dunkelgrau' => [
+            self::CMYK => [
+                'cyan'    =>  0,
+                'magenta' =>  0,
+                'yellow'  =>  0,
+                'key'     => 33,
+            ],
+            self::RGB  => [
+                'red'   => 0xAA,
+                'green' => 0xAA,
+                'blue'  => 0xAA,
+            ],
+            self::HSV  => [
+                'hue'        =>  0,
+                'saturation' =>  0,
+                'value'      => 67,
+            ],
+        ],
+        'schwarz' => [
+            self::CMYK => [
+                'cyan'    =>   0,
+                'magenta' =>   0,
+                'yellow'  =>   0,
+                'key'     => 100,
+            ],
+            self::RGB  => [
+                'red'   => 0,
+                'green' => 0,
+                'blue'  => 0,
+            ],
+            self::HSV  => [
+                'hue'        => 0,
+                'saturation' => 0,
+                'value'      => 0,
+            ],
+        ],
+        'aquamarin' => [
+            self::CMYK => [
+                'cyan'    => 50,
+                'magenta' =>  0,
+                'yellow'  => 17,
+                'key'     =>  0,
+            ],
+            self::RGB  => [
+                'red'   => 0x7F,
+                'green' => 0xFF,
+                'blue'  => 0xD4,
+            ],
+            self::HSV  => [
+                'hue'        => 160,
+                'saturation' =>  50,
+                'value'      => 100,
+            ],
+        ],
+    ];
+
+    /**
+     * @param string $pure_color
+     * @param string $test_color
+     *
+     * @return array<string, array<string, float>[]>
+     */
+    public function getValidColorValues(string $pure_color, string $test_color): array
+    {
+        $values = [];
+        $pure_values = (new ValidColorValuesProvider())->getValidColorValues([$pure_color]);
+        foreach ($this->definitions as $color => $definition) {
+            $values[$color] = [
+                $pure_values[$color][0],
+                $definition[$test_color]
+            ];
+        }
+        return $values;
+    }
+}
\ No newline at end of file
diff --git a/tests/unit/NaturallyTransformer/CyanMagentaYellowKeyTransformerTest.php b/tests/unit/NaturallyTransformer/CyanMagentaYellowKeyTransformerTest.php
new file mode 100644
index 0000000..835b1db
--- /dev/null
+++ b/tests/unit/NaturallyTransformer/CyanMagentaYellowKeyTransformerTest.php
@@ -0,0 +1,121 @@
+<?php
+
+namespace TorstenHettstedt\Colors\Tests\Unit\NaturallyTransformer;
+
+use Codeception\Test\Unit;
+use Exception;
+use TorstenHettstedt\Colors\NaturallyColorModels\CyanMagentaYellowKey;
+use TorstenHettstedt\Colors\Tests\Helper\ValidNaturallyColorValuesProvider;
+use TorstenHettstedt\Colors\NaturallyTransformer\CyanMagentaYellowKeyTransformer;
+
+class CyanMagentaYellowKeyTransformerTest extends Unit
+{
+
+    protected CyanMagentaYellowKey $color;
+
+    /**
+     * @return array<string, array<string, float>[]>
+     */
+    public function validRgbValuesProvider(): array
+    {
+        return (new ValidNaturallyColorValuesProvider())->getValidColorValues(
+            ValidNaturallyColorValuesProvider::CMYK,
+            ValidNaturallyColorValuesProvider::RGB
+        );
+    }
+
+    /**
+     * @return array<string, array<string, float>[]>
+     */
+    public function validHsvValuesProvider(): array
+    {
+        return (new ValidNaturallyColorValuesProvider())->getValidColorValues(
+            ValidNaturallyColorValuesProvider::CMYK,
+            ValidNaturallyColorValuesProvider::HSV
+        );
+    }
+
+    /**
+     * @return array<string, array<string, float>[]>
+     */
+    public function validCmykValuesProvider(): array
+    {
+        return (new ValidNaturallyColorValuesProvider())->getValidColorValues(
+            ValidNaturallyColorValuesProvider::CMYK,
+            ValidNaturallyColorValuesProvider::CMYK
+        );
+    }
+
+    /**
+     * @param array<string, float> $pure_color
+     * @param array<string, float> $rgb
+     *
+     * @dataProvider validRgbValuesProvider
+     *
+     * @throws Exception
+     */
+    public function testToRedGreenBlue(array $pure_color, array $rgb): void
+    {
+        $this->color = $this->make(CyanMagentaYellowKey::class, [
+            'getPureColor' => $this->make(\TorstenHettstedt\Colors\ColorModels\CyanMagentaYellowKey::class, $pure_color)
+        ]);
+
+        $transformer = new CyanMagentaYellowKeyTransformer($this->color);
+
+        $color = $transformer->toRedGreenBlue();
+
+        $this->assertEquals($rgb['red'], $color->getRed());
+        $this->assertEquals($rgb['green'], $color->getGreen());
+        $this->assertEquals($rgb['blue'], $color->getBlue());
+
+    }
+
+    /**
+     * @param array<string, float> $pure_color
+     * @param array<string, float> $cmyk
+     *
+     * @dataProvider validCmykValuesProvider
+     *
+     * @throws Exception
+     */
+    public function testToCyanMagentaYellowKey(array $pure_color, array $cmyk): void
+    {
+
+        $this->color = $this->make(CyanMagentaYellowKey::class, [
+            'getPureColor' => $this->make(\TorstenHettstedt\Colors\ColorModels\CyanMagentaYellowKey::class, $pure_color)
+        ]);
+
+        $transformer = new CyanMagentaYellowKeyTransformer($this->color);
+
+        $color = $transformer->toCyanMagentaYellowKey();
+
+        $this->assertEquals($cmyk['cyan'], $color->getCyan());
+        $this->assertEquals($cmyk['magenta'], $color->getMagenta());
+        $this->assertEquals($cmyk['yellow'], $color->getYellow());
+        $this->assertEquals($cmyk['key'], $color->getKey());
+    }
+
+    /**
+     * @param array<string, float> $pure_color
+     * @param array<string, float> $hsv
+     *
+     * @throws Exception
+     *
+     * @dataProvider validHsvValuesProvider
+     *
+     */
+    public function testToHueSaturationValue(array $pure_color, array $hsv): void
+    {
+        $this->color = $this->make(CyanMagentaYellowKey::class, [
+            'getPureColor' => $this->make(\TorstenHettstedt\Colors\ColorModels\CyanMagentaYellowKey::class, $pure_color)
+        ]);
+
+        $transformer = new CyanMagentaYellowKeyTransformer($this->color);
+
+        $color = $transformer->toHueSaturationValue();
+
+        $this->assertEquals($hsv['hue'], $color->getHue());
+        $this->assertEquals($hsv['saturation'], $color->getSaturation());
+        $this->assertEquals($hsv['value'], $color->getValue());
+    }
+}
diff --git a/tests/unit/NaturallyTransformer/HueSaturationValueTransformerTest.php b/tests/unit/NaturallyTransformer/HueSaturationValueTransformerTest.php
new file mode 100644
index 0000000..b30a793
--- /dev/null
+++ b/tests/unit/NaturallyTransformer/HueSaturationValueTransformerTest.php
@@ -0,0 +1,118 @@
+<?php
+
+namespace TorstenHettstedt\Colors\Tests\Unit\NaturallyTransformer;
+
+use Codeception\Test\Unit;
+use Exception;
+use TorstenHettstedt\Colors\NaturallyColorModels\HueSaturationValue;
+use TorstenHettstedt\Colors\Tests\Helper\ValidNaturallyColorValuesProvider;
+use TorstenHettstedt\Colors\NaturallyTransformer\HueSaturationValueTransformer;
+
+class HueSaturationValueTransformerTest extends Unit
+{
+
+    protected HueSaturationValue $color;
+
+    /**
+     * @return array<string, array<string, float>[]>
+     */
+    public function validCmykValuesProvider(): array
+    {
+        return (new ValidNaturallyColorValuesProvider())->getValidColorValues(
+            ValidNaturallyColorValuesProvider::HSV,
+            ValidNaturallyColorValuesProvider::CMYK,
+        );
+    }
+
+    /**
+     * @return array<string, array<string, float>[]>
+     */
+    public function validRgbValuesProvider(): array
+    {
+        return (new ValidNaturallyColorValuesProvider())->getValidColorValues(
+            ValidNaturallyColorValuesProvider::HSV,
+            ValidNaturallyColorValuesProvider::RGB,
+        );
+    }
+
+    /**
+     * @return array<string, array<string, float>[]>
+     */
+    public function validHsvValuesProvider(): array
+    {
+        return (new ValidNaturallyColorValuesProvider())->getValidColorValues(
+            ValidNaturallyColorValuesProvider::HSV,
+            ValidNaturallyColorValuesProvider::HSV,
+        );
+    }
+
+    /**
+     * @param array<string, float> $pure_color
+     * @param array<string, float> $rgb
+     *
+     * @dataProvider validRgbValuesProvider
+     *
+     * @throws Exception
+     */
+    public function testToRedGreenBlue(array $pure_color, array $rgb): void
+    {
+        $this->color = $this->make(HueSaturationValue::class, [
+            'getPureColor' => $this->make(\TorstenHettstedt\Colors\ColorModels\HueSaturationValue::class, $pure_color)
+        ]);
+
+        $transformer = new HueSaturationValueTransformer($this->color);
+
+        $color = $transformer->toRedGreenBlue();
+
+        $this->assertEquals($rgb['red'], $color->getRed());
+        $this->assertEquals($rgb['green'], $color->getGreen());
+        $this->assertEquals($rgb['blue'], $color->getBlue());
+
+    }
+
+    /**
+     * @param array<string, float> $pure_color
+     * @param array<string, float> $cmyk
+     *
+     * @throws Exception
+     * @dataProvider validCmykValuesProvider
+     *
+     */
+    public function testToCyanMagentaYellowKey(array $pure_color, array $cmyk): void
+    {
+        $this->color = $this->make(HueSaturationValue::class, [
+            'getPureColor' => $this->make(\TorstenHettstedt\Colors\ColorModels\HueSaturationValue::class, $pure_color)
+        ]);
+
+        $transformer = new HueSaturationValueTransformer($this->color);
+
+        $color = $transformer->toCyanMagentaYellowKey();
+
+        $this->assertEquals($cmyk['cyan'], $color->getCyan());
+        $this->assertEquals($cmyk['magenta'], $color->getMagenta());
+        $this->assertEquals($cmyk['yellow'], $color->getYellow());
+        $this->assertEquals($cmyk['key'], $color->getKey());
+    }
+
+    /**
+     * @param array<string, float> $pure_color
+     * @param array<string, float> $hsv
+     *
+     * @throws Exception
+     * @dataProvider validHsvValuesProvider
+     */
+    public function testToHueSaturationValue(array $pure_color, array $hsv): void
+    {
+        $this->color = $this->make(HueSaturationValue::class, [
+            'getPureColor' => $this->make(\TorstenHettstedt\Colors\ColorModels\HueSaturationValue::class, $pure_color)
+        ]);
+
+        $transformer = new HueSaturationValueTransformer($this->color);
+
+        $color = $transformer->toHueSaturationValue();
+
+        $this->assertEquals($hsv['hue'], $color->getHue());
+        $this->assertEquals($hsv['saturation'], $color->getSaturation());
+        $this->assertEquals($hsv['value'], $color->getValue());
+    }
+}
diff --git a/tests/unit/NaturallyTransformer/RedGreenBlueTransformerTest.php b/tests/unit/NaturallyTransformer/RedGreenBlueTransformerTest.php
new file mode 100644
index 0000000..15f8e9f
--- /dev/null
+++ b/tests/unit/NaturallyTransformer/RedGreenBlueTransformerTest.php
@@ -0,0 +1,118 @@
+<?php
+
+namespace TorstenHettstedt\Colors\Tests\Unit\NaturallyTransformer;
+
+use Codeception\Test\Unit;
+use Exception;
+use TorstenHettstedt\Colors\NaturallyColorModels\RedGreenBlue;
+use TorstenHettstedt\Colors\Tests\Helper\ValidNaturallyColorValuesProvider;
+use TorstenHettstedt\Colors\NaturallyTransformer\RedGreenBlueTransformer;
+
+class RedGreenBlueTransformerTest extends Unit
+{
+
+    protected RedGreenBlue $color;
+
+    /**
+     * @return array<string, array<string, float>[]>
+     */
+    public function validCmykValuesProvider(): array
+    {
+        return (new ValidNaturallyColorValuesProvider())->getValidColorValues(
+            ValidNaturallyColorValuesProvider::RGB,
+            ValidNaturallyColorValuesProvider::CMYK,
+        );
+    }
+
+    /**
+     * @return array<string, array<string, float>[]>
+     */
+    public function validHsvValuesProvider(): array
+    {
+        return (new ValidNaturallyColorValuesProvider())->getValidColorValues(
+            ValidNaturallyColorValuesProvider::RGB,
+            ValidNaturallyColorValuesProvider::HSV,
+        );
+    }
+
+    /**
+     * @return array<string, array<string, float>[]>
+     */
+    public function validRgbValuesProvider(): array
+    {
+        return (new ValidNaturallyColorValuesProvider())->getValidColorValues(
+            ValidNaturallyColorValuesProvider::RGB,
+            ValidNaturallyColorValuesProvider::RGB,
+        );
+    }
+
+    /**
+     * @param array<string, float> $pure_color
+     * @param array<string, float> $rgb
+     *
+     * @dataProvider validRgbValuesProvider
+     *
+     * @throws Exception
+     */
+    public function testToRedGreenBlue(array $pure_color, array $rgb): void
+    {
+        $this->color = $this->make(RedGreenBlue::class, [
+            'getPureColor' => $this->make(\TorstenHettstedt\Colors\ColorModels\RedGreenBlue::class, $pure_color)
+        ]);
+
+        $transformer = new RedGreenBlueTransformer($this->color);
+
+        $color = $transformer->toRedGreenBlue();
+
+        $this->assertEquals($rgb['red'], $color->getRed());
+        $this->assertEquals($rgb['green'], $color->getGreen());
+        $this->assertEquals($rgb['blue'], $color->getBlue());
+
+    }
+
+    /**
+     * @param array<string, float> $pure_color
+     * @param array<string, float> $cmyk
+     *
+     * @throws Exception
+     * @dataProvider validCmykValuesProvider
+     *
+     */
+    public function testToCyanMagentaYellowKey(array $pure_color, array $cmyk): void
+    {
+        $this->color = $this->make(RedGreenBlue::class, [
+            'getPureColor' => $this->make(\TorstenHettstedt\Colors\ColorModels\RedGreenBlue::class, $pure_color)
+        ]);
+
+        $transformer = new RedGreenBlueTransformer($this->color);
+
+        $color = $transformer->toCyanMagentaYellowKey();
+
+        $this->assertEquals($cmyk['cyan'], $color->getCyan());
+        $this->assertEquals($cmyk['magenta'], $color->getMagenta());
+        $this->assertEquals($cmyk['yellow'], $color->getYellow());
+        $this->assertEquals($cmyk['key'], $color->getKey());
+    }
+
+    /**
+     * @param array<string, float> $pure_color
+     * @param array<string, float> $hsv
+     *
+     * @throws Exception
+     * @dataProvider validHsvValuesProvider
+     */
+    public function testToHueSaturationValue(array $pure_color, array $hsv): void
+    {
+        $this->color = $this->make(RedGreenBlue::class, [
+            'getPureColor' => $this->make(\TorstenHettstedt\Colors\ColorModels\RedGreenBlue::class, $pure_color)
+        ]);
+
+        $transformer = new RedGreenBlueTransformer($this->color);
+
+        $color = $transformer->toHueSaturationValue();
+
+        $this->assertEquals($hsv['hue'], $color->getHue());
+        $this->assertEquals($hsv['saturation'], $color->getSaturation());
+        $this->assertEquals($hsv['value'], $color->getValue());
+    }
+}