diff --git a/tests/BaseTestCase.php b/tests/BaseTestCase.php
index 3b162c29..849cbe73 100644
--- a/tests/BaseTestCase.php
+++ b/tests/BaseTestCase.php
@@ -16,17 +16,17 @@ use PHPUnit\Framework\ExpectationFailedException;
 
 abstract class BaseTestCase extends MockeryTestCase
 {
-    public static function getTestResourcePath($filename = 'test.jpg'): string
+    public static function getTestResourcePath(string $filename = 'test.jpg'): string
     {
         return sprintf('%s/resources/%s', __DIR__, $filename);
     }
 
-    public static function getTestResourceData($filename = 'test.jpg'): string
+    public static function getTestResourceData(string $filename = 'test.jpg'): string
     {
         return file_get_contents(self::getTestResourcePath($filename));
     }
 
-    public static function getTestResourcePointer($filename = 'test.jpg')
+    public static function getTestResourcePointer(string $filename = 'test.jpg'): mixed
     {
         $pointer = fopen('php://temp', 'rw');
         fwrite($pointer, self::getTestResourceData($filename));
@@ -39,9 +39,8 @@ abstract class BaseTestCase extends MockeryTestCase
      * Assert that given color equals the given color channel values in the given optional tolerance
      *
      * @throws ExpectationFailedException
-     * @return void
      */
-    protected function assertColor(int $r, int $g, int $b, int $a, ColorInterface $color, int $tolerance = 0)
+    protected function assertColor(int $r, int $g, int $b, int $a, ColorInterface $color, int $tolerance = 0): void
     {
         // build errorMessage
         $errorMessage = function (int $r, int $g, $b, int $a, ColorInterface $color): string {
@@ -90,7 +89,7 @@ abstract class BaseTestCase extends MockeryTestCase
         );
     }
 
-    protected function assertTransparency(ColorInterface $color)
+    protected function assertTransparency(ColorInterface $color): void
     {
         $this->assertInstanceOf(RgbColor::class, $color);
         $channel = $color->channel(Alpha::class);
diff --git a/tests/GdTestCase.php b/tests/GdTestCase.php
index ebe98a01..559d8067 100644
--- a/tests/GdTestCase.php
+++ b/tests/GdTestCase.php
@@ -12,7 +12,7 @@ use Intervention\Image\Image;
 
 abstract class GdTestCase extends BaseTestCase
 {
-    public static function readTestImage($filename = 'test.jpg'): Image
+    public static function readTestImage(string $filename = 'test.jpg'): Image
     {
         return (new Driver())->specialize(new FilePathImageDecoder())->decode(
             static::getTestResourcePath($filename)
diff --git a/tests/ImagickTestCase.php b/tests/ImagickTestCase.php
index 6c4f8ecc..3055c1ff 100644
--- a/tests/ImagickTestCase.php
+++ b/tests/ImagickTestCase.php
@@ -14,7 +14,7 @@ use Intervention\Image\Image;
 
 abstract class ImagickTestCase extends BaseTestCase
 {
-    public static function readTestImage($filename = 'test.jpg'): Image
+    public static function readTestImage(string $filename = 'test.jpg'): Image
     {
         return (new Driver())->specialize(new FilePathImageDecoder())->decode(
             static::getTestResourcePath($filename)
diff --git a/tests/Unit/Colors/Hsl/Decoders/StringColorDecoderTest.php b/tests/Unit/Colors/Hsl/Decoders/StringColorDecoderTest.php
index 447ebd64..7a087835 100644
--- a/tests/Unit/Colors/Hsl/Decoders/StringColorDecoderTest.php
+++ b/tests/Unit/Colors/Hsl/Decoders/StringColorDecoderTest.php
@@ -14,6 +14,9 @@ use PHPUnit\Framework\Attributes\DataProvider;
 #[CoversClass(StringColorDecoder::class)]
 final class StringColorDecoderTest extends BaseTestCase
 {
+    /**
+     * @param $channelValues array<int>
+     */
     #[DataProvider('decodeDataProvier')]
     public function testDecode(string $input, string $classname, array $channelValues): void
     {
diff --git a/tests/Unit/Colors/Hsv/Decoders/StringColorDecoderTest.php b/tests/Unit/Colors/Hsv/Decoders/StringColorDecoderTest.php
index 34da0874..2bd49791 100644
--- a/tests/Unit/Colors/Hsv/Decoders/StringColorDecoderTest.php
+++ b/tests/Unit/Colors/Hsv/Decoders/StringColorDecoderTest.php
@@ -14,6 +14,9 @@ use PHPUnit\Framework\Attributes\DataProvider;
 #[CoversClass(StringColorDecoder::class)]
 final class StringColorDecoderTest extends BaseTestCase
 {
+    /**
+     * @param $channelValues array<int>
+     */
     #[DataProvider('decodeDataProvier')]
     public function testDecodeHsv(string $input, string $classname, array $channelValues): void
     {
diff --git a/tests/Unit/Colors/Rgb/Decoders/HexColorDecoderTest.php b/tests/Unit/Colors/Rgb/Decoders/HexColorDecoderTest.php
index 3d510f4e..ee060001 100644
--- a/tests/Unit/Colors/Rgb/Decoders/HexColorDecoderTest.php
+++ b/tests/Unit/Colors/Rgb/Decoders/HexColorDecoderTest.php
@@ -14,6 +14,9 @@ use PHPUnit\Framework\Attributes\DataProvider;
 #[CoversClass(HexColorDecoder::class)]
 final class HexColorDecoderTest extends BaseTestCase
 {
+    /**
+     * @param $channelValues array<int>
+     */
     #[DataProvider('decodeDataProvier')]
     public function testDecode(string $input, string $classname, array $channelValues): void
     {
diff --git a/tests/Unit/Colors/Rgb/Decoders/HtmlColornameDecoderTest.php b/tests/Unit/Colors/Rgb/Decoders/HtmlColornameDecoderTest.php
index ddb88f9f..74f1f088 100644
--- a/tests/Unit/Colors/Rgb/Decoders/HtmlColornameDecoderTest.php
+++ b/tests/Unit/Colors/Rgb/Decoders/HtmlColornameDecoderTest.php
@@ -14,6 +14,9 @@ use PHPUnit\Framework\Attributes\DataProvider;
 #[CoversClass(HtmlColorNameDecoder::class)]
 final class HtmlColornameDecoderTest extends BaseTestCase
 {
+    /**
+     * @param $channelValues array<int>
+     */
     #[DataProvider('decodeDataProvier')]
     public function testDecode(string $input, string $classname, array $channelValues): void
     {
diff --git a/tests/Unit/Colors/Rgb/Decoders/StringColorDecoderTest.php b/tests/Unit/Colors/Rgb/Decoders/StringColorDecoderTest.php
index 951406c8..ddb4edb3 100644
--- a/tests/Unit/Colors/Rgb/Decoders/StringColorDecoderTest.php
+++ b/tests/Unit/Colors/Rgb/Decoders/StringColorDecoderTest.php
@@ -14,6 +14,9 @@ use PHPUnit\Framework\Attributes\DataProvider;
 #[CoversClass(StringColorDecoder::class)]
 final class StringColorDecoderTest extends BaseTestCase
 {
+    /**
+     * @param $channelValues array<int>
+     */
     #[DataProvider('decodeDataProvier')]
     public function testDecode(string $input, string $classname, array $channelValues): void
     {
diff --git a/tests/Unit/Drivers/Gd/DriverTest.php b/tests/Unit/Drivers/Gd/DriverTest.php
index 174a5293..366653c5 100644
--- a/tests/Unit/Drivers/Gd/DriverTest.php
+++ b/tests/Unit/Drivers/Gd/DriverTest.php
@@ -45,7 +45,7 @@ final class DriverTest extends BaseTestCase
 
     public function testCreateAnimation(): void
     {
-        $image = $this->driver->createAnimation(function ($animation) {
+        $image = $this->driver->createAnimation(function ($animation): void {
             $animation->add($this->getTestResourcePath('red.gif'), .25);
             $animation->add($this->getTestResourcePath('green.gif'), .25);
         })->setLoops(5);
diff --git a/tests/Unit/Drivers/Gd/Modifiers/TextModifierTest.php b/tests/Unit/Drivers/Gd/Modifiers/TextModifierTest.php
index 3bd1f503..7f657e68 100644
--- a/tests/Unit/Drivers/Gd/Modifiers/TextModifierTest.php
+++ b/tests/Unit/Drivers/Gd/Modifiers/TextModifierTest.php
@@ -24,7 +24,7 @@ final class TextModifierTest extends GdTestCase
 
         $modifier = new class ('test', new Point(), $font) extends TextModifier
         {
-            public function test()
+            public function test(): ColorInterface
             {
                 return $this->textColor();
             }
diff --git a/tests/Unit/Drivers/Imagick/DriverTest.php b/tests/Unit/Drivers/Imagick/DriverTest.php
index 494b002b..f69a5056 100644
--- a/tests/Unit/Drivers/Imagick/DriverTest.php
+++ b/tests/Unit/Drivers/Imagick/DriverTest.php
@@ -45,7 +45,7 @@ final class DriverTest extends BaseTestCase
 
     public function testCreateAnimation(): void
     {
-        $image = $this->driver->createAnimation(function ($animation) {
+        $image = $this->driver->createAnimation(function ($animation): void {
             $animation->add($this->getTestResourcePath('red.gif'), .25);
             $animation->add($this->getTestResourcePath('green.gif'), .25);
         })->setLoops(5);
diff --git a/tests/Unit/Drivers/Imagick/Modifiers/TextModifierTest.php b/tests/Unit/Drivers/Imagick/Modifiers/TextModifierTest.php
index 232b6c3e..8de39300 100644
--- a/tests/Unit/Drivers/Imagick/Modifiers/TextModifierTest.php
+++ b/tests/Unit/Drivers/Imagick/Modifiers/TextModifierTest.php
@@ -24,7 +24,7 @@ final class TextModifierTest extends ImagickTestCase
 
         $modifier = new class ('test', new Point(), $font) extends TextModifier
         {
-            public function test()
+            public function test(): ColorInterface
             {
                 return $this->textColor();
             }
diff --git a/tests/Unit/Encoders/FileExtensionEncoderTest.php b/tests/Unit/Encoders/FileExtensionEncoderTest.php
index d44597be..89dc814b 100644
--- a/tests/Unit/Encoders/FileExtensionEncoderTest.php
+++ b/tests/Unit/Encoders/FileExtensionEncoderTest.php
@@ -25,16 +25,19 @@ use PHPUnit\Framework\Attributes\DataProvider;
 #[CoversClass(FileExtensionEncoder::class)]
 final class FileExtensionEncoderTest extends BaseTestCase
 {
+    /**
+     * @param $options array<string, int>
+     */
     private function testEncoder(string|FileExtension $extension, array $options = []): EncoderInterface
     {
         $encoder = new class ($extension, ...$options) extends FileExtensionEncoder
         {
-            public function __construct($mediaType, ...$options)
+            public function __construct(string|FileExtension $extension, mixed ...$options)
             {
-                parent::__construct($mediaType, ...$options);
+                parent::__construct($extension, ...$options);
             }
 
-            public function test($extension)
+            public function test(string|FileExtension $extension): EncoderInterface
             {
                 return $this->encoderByFileExtension($extension);
             }
diff --git a/tests/Unit/Encoders/MediaTypeEncoderTest.php b/tests/Unit/Encoders/MediaTypeEncoderTest.php
index d78c38e7..563c48f2 100644
--- a/tests/Unit/Encoders/MediaTypeEncoderTest.php
+++ b/tests/Unit/Encoders/MediaTypeEncoderTest.php
@@ -25,16 +25,19 @@ use PHPUnit\Framework\Attributes\DataProvider;
 #[CoversClass(MediaTypeEncoder::class)]
 final class MediaTypeEncoderTest extends BaseTestCase
 {
+    /**
+     * @param $options array<string, int>
+     */
     private function testEncoder(string|MediaType $mediaType, array $options = []): EncoderInterface
     {
         $encoder = new class ($mediaType, ...$options) extends MediaTypeEncoder
         {
-            public function __construct($mediaType, ...$options)
+            public function __construct(string|MediaType $mediaType, mixed ...$options)
             {
                 parent::__construct($mediaType, ...$options);
             }
 
-            public function test($mediaType)
+            public function test(string|MediaType $mediaType): EncoderInterface
             {
                 return $this->encoderByMediaType($mediaType);
             }
diff --git a/tests/Unit/Geometry/Factories/BezierFactoryTest.php b/tests/Unit/Geometry/Factories/BezierFactoryTest.php
index 483dbda1..a0c599e6 100644
--- a/tests/Unit/Geometry/Factories/BezierFactoryTest.php
+++ b/tests/Unit/Geometry/Factories/BezierFactoryTest.php
@@ -14,7 +14,7 @@ final class BezierFactoryTest extends BaseTestCase
 {
     public function testFactoryCallback(): void
     {
-        $factory = new BezierFactory(function ($bezier) {
+        $factory = new BezierFactory(function ($bezier): void {
             $bezier->background('f00');
             $bezier->border('ff0', 10);
             $bezier->point(300, 260);
diff --git a/tests/Unit/Geometry/Factories/CircleFactoryTest.php b/tests/Unit/Geometry/Factories/CircleFactoryTest.php
index 1a830f64..94663c39 100644
--- a/tests/Unit/Geometry/Factories/CircleFactoryTest.php
+++ b/tests/Unit/Geometry/Factories/CircleFactoryTest.php
@@ -15,7 +15,7 @@ final class CircleFactoryTest extends BaseTestCase
 {
     public function testFactoryCallback(): void
     {
-        $factory = new CircleFactory(new Point(1, 2), function ($circle) {
+        $factory = new CircleFactory(new Point(1, 2), function ($circle): void {
             $circle->background('fff');
             $circle->border('ccc', 10);
             $circle->radius(100);
diff --git a/tests/Unit/Geometry/Factories/EllipseFactoryTest.php b/tests/Unit/Geometry/Factories/EllipseFactoryTest.php
index 0b9bb970..481011d3 100644
--- a/tests/Unit/Geometry/Factories/EllipseFactoryTest.php
+++ b/tests/Unit/Geometry/Factories/EllipseFactoryTest.php
@@ -15,7 +15,7 @@ final class EllipseFactoryTest extends BaseTestCase
 {
     public function testFactoryCallback(): void
     {
-        $factory = new EllipseFactory(new Point(1, 2), function ($ellipse) {
+        $factory = new EllipseFactory(new Point(1, 2), function ($ellipse): void {
             $ellipse->background('fff');
             $ellipse->border('ccc', 10);
             $ellipse->width(100);
diff --git a/tests/Unit/Geometry/Factories/LineFactoryTest.php b/tests/Unit/Geometry/Factories/LineFactoryTest.php
index f3c3483c..7e96a5c7 100644
--- a/tests/Unit/Geometry/Factories/LineFactoryTest.php
+++ b/tests/Unit/Geometry/Factories/LineFactoryTest.php
@@ -14,7 +14,7 @@ final class LineFactoryTest extends BaseTestCase
 {
     public function testFactoryCallback(): void
     {
-        $factory = new LineFactory(function ($line) {
+        $factory = new LineFactory(function ($line): void {
             $line->color('fff');
             $line->background('fff');
             $line->border('fff', 10);
diff --git a/tests/Unit/Geometry/Factories/PolygonFactoryTest.php b/tests/Unit/Geometry/Factories/PolygonFactoryTest.php
index 284dc04f..f652aba5 100644
--- a/tests/Unit/Geometry/Factories/PolygonFactoryTest.php
+++ b/tests/Unit/Geometry/Factories/PolygonFactoryTest.php
@@ -14,7 +14,7 @@ final class PolygonFactoryTest extends BaseTestCase
 {
     public function testFactoryCallback(): void
     {
-        $factory = new PolygonFactory(function ($polygon) {
+        $factory = new PolygonFactory(function ($polygon): void {
             $polygon->background('fff');
             $polygon->border('ccc', 10);
             $polygon->point(1, 2);
diff --git a/tests/Unit/Geometry/Factories/RectangleFactoryTest.php b/tests/Unit/Geometry/Factories/RectangleFactoryTest.php
index b14b3bb1..1b183ef8 100644
--- a/tests/Unit/Geometry/Factories/RectangleFactoryTest.php
+++ b/tests/Unit/Geometry/Factories/RectangleFactoryTest.php
@@ -15,7 +15,7 @@ final class RectangleFactoryTest extends BaseTestCase
 {
     public function testFactoryCallback(): void
     {
-        $factory = new RectangleFactory(new Point(1, 2), function ($rectangle) {
+        $factory = new RectangleFactory(new Point(1, 2), function ($rectangle): void {
             $rectangle->background('fff');
             $rectangle->border('ccc', 10);
             $rectangle->width(100);
diff --git a/tests/Unit/Geometry/RectangleResizerTest.php b/tests/Unit/Geometry/RectangleResizerTest.php
index 66cb3117..ace8d48e 100644
--- a/tests/Unit/Geometry/RectangleResizerTest.php
+++ b/tests/Unit/Geometry/RectangleResizerTest.php
@@ -51,6 +51,9 @@ final class RectangleResizerTest extends TestCase
         $this->assertInstanceOf(RectangleResizer::class, $resizer);
     }
 
+    /**
+     * @param $resizeParameters array<string, int>
+     */
     #[DataProvider('resizeDataProvider')]
     public function testResize(Rectangle $input, array $resizeParameters, Rectangle $result): void
     {
@@ -68,6 +71,9 @@ final class RectangleResizerTest extends TestCase
         yield [new Rectangle(300, 200), [], new Rectangle(300, 200)];
     }
 
+    /**
+     * @param $resizeParameters array<string, int>
+     */
     #[DataProvider('resizeDownDataProvider')]
     public function testResizeDown(Rectangle $input, array $resizeParameters, Rectangle $result): void
     {
@@ -88,6 +94,9 @@ final class RectangleResizerTest extends TestCase
         yield [new Rectangle(800, 600), [], new Rectangle(800, 600)];
     }
 
+    /**
+     * @param $resizeParameters array<string, int>
+     */
     #[DataProvider('scaleDataProvider')]
     public function testScale(Rectangle $input, array $resizeParameters, Rectangle $result): void
     {
@@ -119,6 +128,9 @@ final class RectangleResizerTest extends TestCase
         yield [new Rectangle(800, 600), [], new Rectangle(800, 600)];
     }
 
+    /**
+     * @param $resizeParameters array<string, int>
+     */
     #[DataProvider('scaleDownDataProvider')]
     public function testScaleDown(Rectangle $input, array $resizeParameters, Rectangle $result): void
     {
diff --git a/tests/Unit/ImageManagerTestGd.php b/tests/Unit/ImageManagerTestGd.php
index 78352096..3a246d4b 100644
--- a/tests/Unit/ImageManagerTestGd.php
+++ b/tests/Unit/ImageManagerTestGd.php
@@ -58,7 +58,7 @@ final class ImageManagerTestGd extends BaseTestCase
     public function testAnimate(): void
     {
         $manager = new ImageManager(Driver::class);
-        $image = $manager->animate(function ($animation) {
+        $image = $manager->animate(function ($animation): void {
             $animation->add($this->getTestResourcePath('red.gif'), .25);
         });
         $this->assertInstanceOf(ImageInterface::class, $image);
diff --git a/tests/Unit/ImageManagerTestImagick.php b/tests/Unit/ImageManagerTestImagick.php
index 422229b1..a3e392f6 100644
--- a/tests/Unit/ImageManagerTestImagick.php
+++ b/tests/Unit/ImageManagerTestImagick.php
@@ -58,7 +58,7 @@ final class ImageManagerTestImagick extends BaseTestCase
     public function testAnimate(): void
     {
         $manager = new ImageManager(Driver::class);
-        $image = $manager->animate(function ($animation) {
+        $image = $manager->animate(function ($animation): void {
             $animation->add($this->getTestResourcePath('red.gif'), .25);
         });
         $this->assertInstanceOf(ImageInterface::class, $image);
diff --git a/tests/Unit/Modifiers/TextModifierTest.php b/tests/Unit/Modifiers/TextModifierTest.php
index a8d98916..241855fe 100644
--- a/tests/Unit/Modifiers/TextModifierTest.php
+++ b/tests/Unit/Modifiers/TextModifierTest.php
@@ -18,7 +18,10 @@ final class TextModifierTest extends BaseTestCase
     {
         $modifier = new class ('test', new Point(), new Font()) extends TextModifier
         {
-            public function testStrokeOffsets(FontInterface $font)
+            /**
+             * @return array<?Point>
+             */
+            public function testStrokeOffsets(FontInterface $font): array
             {
                 return $this->strokeOffsets($font);
             }
diff --git a/tests/Unit/Typography/FontFactoryTest.php b/tests/Unit/Typography/FontFactoryTest.php
index 277bf399..626ba36e 100644
--- a/tests/Unit/Typography/FontFactoryTest.php
+++ b/tests/Unit/Typography/FontFactoryTest.php
@@ -24,7 +24,7 @@ final class FontFactoryTest extends BaseTestCase
 
     public function testBuildWithCallback(): void
     {
-        $factory = new FontFactory(function (FontFactory $font) {
+        $factory = new FontFactory(function (FontFactory $font): void {
             $font->filename($this->getTestResourcePath('test.ttf'));
             $font->color('#b01735');
             $font->size(70);