diff --git a/.github/workflows/on-pull-request.yml b/.github/workflows/on-pull-request.yml
index 4375b3d..fac84f4 100644
--- a/.github/workflows/on-pull-request.yml
+++ b/.github/workflows/on-pull-request.yml
@@ -31,6 +31,8 @@ jobs:
         run: composer install --no-progress --no-dev --prefer-dist --optimize-autoloader
       - name: Composer install with dev
         run: composer install --no-progress --prefer-dist --optimize-autoloader
+      - name: phpcs
+        run: composer phpcs
       - name: PHPUnit
         run: composer test
 
diff --git a/composer.json b/composer.json
index 7a6abe7..53c52ac 100644
--- a/composer.json
+++ b/composer.json
@@ -8,7 +8,8 @@
 	],
 	"type": "library",
 	"require-dev": {
-		"phpunit/phpunit": "^12.0"
+		"phpunit/phpunit": "^12.0",
+		"squizlabs/php_codesniffer": "^3.9"
 	},
 	"require": {
 		"ext-json": "*",
@@ -32,6 +33,8 @@
 		}
 	},
 	"scripts": {
-		"test": "phpunit"
+		"test": "phpunit",
+		"phpcs": "phpcs",
+		"phpcbf": "phpcbf"
 	}
 }
diff --git a/phpcs.xml b/phpcs.xml
new file mode 100644
index 0000000..88ed800
--- /dev/null
+++ b/phpcs.xml
@@ -0,0 +1,7 @@
+<?xml version="1.0"?>
+<ruleset name="ObjectErrors PSR-12">
+    <description>PHP_CodeSniffer configuration for ObjectErrors using PSR-12</description>
+    <rule ref="PSR12"/>
+    <file>src</file>
+    <file>tests</file>
+</ruleset>
diff --git a/src/ErrorsCollection.php b/src/ErrorsCollection.php
index b51271e..8c389e8 100644
--- a/src/ErrorsCollection.php
+++ b/src/ErrorsCollection.php
@@ -24,9 +24,8 @@ class ErrorsCollection implements ArrayAccess, Countable, JsonSerializable, Stri
      * @param ParamsMode $mode Mode how this errors collection works
      */
     public function __construct(
-		public readonly ParamsMode $mode = ParamsMode::Mode1
-	)
-    {
+        public readonly ParamsMode $mode = ParamsMode::Mode1
+    ) {
     }
 
     /**
@@ -116,8 +115,8 @@ public function __toString(): string
             return '';
         }
 
-		return implode(PHP_EOL, $this->errors);
-	}
+        return implode(PHP_EOL, $this->errors);
+    }
 
     /**
      * Adds an
@@ -188,14 +187,13 @@ public function toArray(): array
         return $this->errors;
     }
 
-	/**
-	 * Export data to json
-	 *
-	 * @throws JsonException
-	 */
+    /**
+     * Export data to json
+     *
+     * @throws JsonException
+     */
     public function toJson(): string
     {
         return json_encode($this, JSON_THROW_ON_ERROR);
     }
-
-}
\ No newline at end of file
+}
diff --git a/src/ErrorsTrait.php b/src/ErrorsTrait.php
index 0ff9620..340770f 100644
--- a/src/ErrorsTrait.php
+++ b/src/ErrorsTrait.php
@@ -8,56 +8,54 @@
  */
 trait ErrorsTrait
 {
-
-	/**
-	 * Errors collection
-	 */
-	protected ErrorsCollection $errors;
-
-	/**
-	 * ErrorsTrait constructor.
-	 */
-	public function __construct()
-	{
-		$this->errors = new ErrorsCollection();
-	}
-
-	/**
-	 * return the errors for this object as an array
-	 *
-	 * @param    bool $asHTML Format using HTML?
-	 *
-	 * @return array|string an array of errors
-	 */
-	public function getErrors(bool $asHTML = true): array|string
-	{
-		return $asHTML ? $this->getHtmlErrors() : $this->errors->toArray();
-	}
-
-	/**
-	 * add an error
-	 *
-	 * @param string $err_str error to add
-	 */
-	public function setErrors(string $err_str): void
-	{
-		call_user_func_array([$this->errors, 'add'], func_get_args());
-	}
-
-	/**
-	 * Returns the errors for this object as html
-	 */
-	public function getHtmlErrors(): string
-	{
-		return $this->errors->getHtml();
-	}
-
-	/**
-	 * Has some errors?
-	 */
-	public function hasError(): bool
-	{
-		return !$this->errors->isEmpty();
-	}
-
-}
\ No newline at end of file
+    /**
+     * Errors collection
+     */
+    protected ErrorsCollection $errors;
+
+    /**
+     * ErrorsTrait constructor.
+     */
+    public function __construct()
+    {
+        $this->errors = new ErrorsCollection();
+    }
+
+    /**
+     * return the errors for this object as an array
+     *
+     * @param    bool $asHTML Format using HTML?
+     *
+     * @return array|string an array of errors
+     */
+    public function getErrors(bool $asHTML = true): array|string
+    {
+        return $asHTML ? $this->getHtmlErrors() : $this->errors->toArray();
+    }
+
+    /**
+     * add an error
+     *
+     * @param string $err_str error to add
+     */
+    public function setErrors(string $err_str): void
+    {
+        call_user_func_array([$this->errors, 'add'], func_get_args());
+    }
+
+    /**
+     * Returns the errors for this object as html
+     */
+    public function getHtmlErrors(): string
+    {
+        return $this->errors->getHtml();
+    }
+
+    /**
+     * Has some errors?
+     */
+    public function hasError(): bool
+    {
+        return !$this->errors->isEmpty();
+    }
+}
diff --git a/src/ParamsMode.php b/src/ParamsMode.php
index 13b10a6..85e4611 100644
--- a/src/ParamsMode.php
+++ b/src/ParamsMode.php
@@ -6,20 +6,18 @@
 
 enum ParamsMode: int
 {
+    /**
+     * Mode that says that only one param for adding is used
+     */
+    case Mode1 = 0;
 
-	/**
-	 * Mode that says that only one param for adding is used
-	 */
-	case Mode1 = 0;
-
-	/**
-	 * Mode that says two params are used
-	 */
-	case Mode2 = 1;
-
-	/**
-	 * Mode that says that 2nd param is a used as prefix
-	 */
-	case Mode2AsPrefix = 2;
+    /**
+     * Mode that says two params are used
+     */
+    case Mode2 = 1;
 
+    /**
+     * Mode that says that 2nd param is a used as prefix
+     */
+    case Mode2AsPrefix = 2;
 }
diff --git a/src/UnsetErrorException.php b/src/UnsetErrorException.php
index d2735dc..7c855d6 100644
--- a/src/UnsetErrorException.php
+++ b/src/UnsetErrorException.php
@@ -6,5 +6,4 @@
 
 class UnsetErrorException extends Exception
 {
-
-}
\ No newline at end of file
+}
diff --git a/tests/ErrorsCollectionTest.php b/tests/ErrorsCollectionTest.php
index 9682c54..074fadb 100644
--- a/tests/ErrorsCollectionTest.php
+++ b/tests/ErrorsCollectionTest.php
@@ -12,202 +12,227 @@
 
 class ErrorsCollectionTest extends TestCase
 {
-
-	public function testDefaultConstructorParams(): void
-	{
-		$instance = new ErrorsCollection();
-		$this->assertSame(
-			ParamsMode::Mode1,
-			$instance->mode,
-			message: 'When creating ErrorsCollection instance default mode should be MODE_1_PARAM, but isn\'t'
-		);
-	}
-
-	#[DataProvider('provideConstructorParams')]
-	public function testConstructorParams(ParamsMode $mode): void
-	{
-		$instance = new ErrorsCollection($mode);
-		$this->assertSame(
-			$mode,
-			$instance->mode,
-			message: 'Mode ' . $mode->name . ' is different after creating instance'
-		);
-	}
-
-	public function testOffsetExists(): void
-	{
-		$instance = new ErrorsCollection(ParamsMode::Mode2);
-		$key = crc32(time());
-		$this->assertArrayNotHasKey(
-			$key,
-			$instance,
-			message: 'Random key already exists in array but shouldn\'t'
-		);
-		$instance->add($key, crc32(time()));
-		$this->assertArrayHasKey(
-			$key,
-			$instance,
-			message: 'Random key was not found but it should'
-		);
-	}
-
-	public function testOffsetGet(): void
-	{
-		$offset = crc32(time());
-		$data = sha1(time());
-
-		$instance = new ErrorsCollection(ParamsMode::Mode2);
-		$instance->add($offset, $data);
-		$this->assertSame($instance[$offset], $data, message: 'Data is not same #1');
-		$this->assertSame($instance->offsetGet($offset), $data, message: 'Data is not same #2');
-		$this->assertNotNull($instance[$offset], message: 'Data is not same #3');
-		$this->assertNotNull($instance->offsetGet($offset), message: 'Data is not same #4');
-	}
-
-	public function testOffsetSet(): void
-	{
-		$offset = crc32(time());
-		$data = sha1(time());
-
-		$instance = new ErrorsCollection(ParamsMode::Mode2);
-		$instance->add($offset, $data);
-
-		$ndata = md5(time());
-		$instance[$offset] = $ndata;
-		$this->assertSame($instance[$offset], $ndata, message: 'Changed data is not same as readed one #1');
-
-		$ndata = soundex($ndata);
-		$instance->offsetSet($offset, $ndata);
-		$this->assertSame($instance[$offset], $ndata, message: 'Changed data is not same as readed one #2');
-
-		$offset = md5(microtime(true));
-
-		$ndata = metaphone($ndata);
-		$instance[$offset] = $ndata;
-		$this->assertSame($instance[$offset], $ndata, message: 'Changed data is not same as readed one #3');
-
-		$ndata = soundex($ndata);
-		$instance->offsetSet($offset, $ndata);
-		$this->assertSame($instance[$offset], $ndata, message: 'Changed data is not same as readed one #4');
-	}
-
-	public function testOffsetUnset(): void
-	{
-		$offset = crc32(time());
-
-		$instance = new ErrorsCollection(ParamsMode::Mode2);
-
-		$this->expectException(UnsetErrorException::class);
-		$instance->offsetUnset($offset);
-	}
-
-	public function testIsEmpty(): void
-	{
-		$instance = new ErrorsCollection();
-		$this->assertTrue($instance->isEmpty(), message: 'Is not empty after creation');
-
-		$instance->add(crc32(time()));
-		$this->assertNotTrue($instance->isEmpty(), message: 'Is still empty after one element was added');
-	}
-
-	public function testClear(): void
-	{
-		$instance = new ErrorsCollection();
-		$instance->add(crc32(time()));
-		$instance->clear();
-		$this->assertEmpty($instance, message: 'Clear() must clear');
-	}
-
-	public function testStringConversion(): void
-	{
-		$instance = new ErrorsCollection();
-
-		$this->assertEmpty((string)$instance, message: 'Converted to string empty ErrorsCollection must be empty');
-		$this->assertEmpty($instance->getHtml(), message: 'Converted to HTML empty ErrorsCollection must be empty');
-
-		$instance->add(crc32(time()));
-
-		$this->assertNotEmpty((string)$instance, message: 'Converted to string not empty ErrorsCollection must be not empty');
-		$this->assertNotEmpty($instance->getHtml(), message: 'Converted to HTML not empty ErrorsCollection must be not empty');
-
-		$this->assertIsString($instance->getHtml(), message: 'getHTML must generate strings');
-	}
-
-	public function testCount(): void
-	{
-		$instance = new ErrorsCollection();
-		$this->assertCount(0, $instance, message: 'Count is not 0 when collection was just created');
-
-		$instance->add(crc32(time()));
-		$this->assertSame(1, $instance->count(), message: 'Count must be 1 after one element was added');
-
-		$this->assertCount(1, $instance, message: 'Count function doesn\'t work');
-	}
-
-	public static function provideTestAddData(): Generator
-	{
-		yield 'mode1' => [
-			'mode' => ParamsMode::Mode1,
-			'addParams' => [
-				md5(time())
-			],
-			'expectedKey' => 0
-		];
-
-		yield 'mode2asprefix' => [
-			'mode' => ParamsMode::Mode2AsPrefix,
-			'addParams' => [
-				md5(time())
-			],
-			'expectedKey' => 0
-		];
-
-		$key = crc32(time());
-		yield 'mode2' => [
-			'mode' => ParamsMode::Mode2,
-			'addParams' => [
-				$key,
-				md5(time())
-			],
-			'expectedKey' => $key
-		];
-	}
-
-	#[DataProvider('provideTestAddData')]
-	public function testAdd(ParamsMode $mode, array $addParams, int|string $expectedKey): void
-	{
-		$instance = new ErrorsCollection($mode);
-		call_user_func_array([$instance, 'add'], $addParams);
-		$this->assertArrayHasKey($expectedKey, $instance);
-	}
-
-	/**
-	 * @throws JsonException
-	 */
-	public function testSerialization(): void
-	{
-		$instance = new ErrorsCollection(ParamsMode::Mode2);
-
-		$instance->add(md5(time()), sha1(time()));
-		$instance->add(crc32(time()), soundex(time()));
-
-		$serialized = serialize($instance);
-		$unserialized = unserialize($serialized);
-		$this->assertInstanceOf(ErrorsCollection::class, $unserialized, message: 'Unserialized data is not ErrorsCollection class type but it should be #1');
-		$this->assertSame($instance->mode, $unserialized->mode, message: 'Serialization-unserialization fails #1');
-		$this->assertSame($instance->toArray(), $unserialized->toArray(), message: 'Serialization-unserialization fails #2');
-
-		$this->assertIsArray($instance->toArray(), message: 'toArray doesn\'t makes an array');
-		$this->assertIsString($instance->toJson(), message: 'toJSON doesn\'t makes a string');
-	}
-
-	public static function provideConstructorParams(): Generator
-	{
-		foreach (ParamsMode::cases() as $mode) {
-			yield $mode->name => [
-				'mode' => $mode,
-			];
-		}
-	}
-
-}
\ No newline at end of file
+    public function testDefaultConstructorParams(): void
+    {
+        $instance = new ErrorsCollection();
+        $this->assertSame(
+            ParamsMode::Mode1,
+            $instance->mode,
+            message: 'When creating ErrorsCollection instance default mode should be MODE_1_PARAM, but isn\'t'
+        );
+    }
+
+    #[DataProvider('provideConstructorParams')]
+    public function testConstructorParams(ParamsMode $mode): void
+    {
+        $instance = new ErrorsCollection($mode);
+        $this->assertSame(
+            $mode,
+            $instance->mode,
+            message: 'Mode ' . $mode->name . ' is different after creating instance'
+        );
+    }
+
+    public function testOffsetExists(): void
+    {
+        $instance = new ErrorsCollection(ParamsMode::Mode2);
+        $key = crc32(time());
+        $this->assertArrayNotHasKey(
+            $key,
+            $instance,
+            message: 'Random key already exists in array but shouldn\'t'
+        );
+        $instance->add($key, crc32(time()));
+        $this->assertArrayHasKey(
+            $key,
+            $instance,
+            message: 'Random key was not found but it should'
+        );
+    }
+
+    public function testOffsetGet(): void
+    {
+        $offset = crc32(time());
+        $data = sha1(time());
+
+        $instance = new ErrorsCollection(ParamsMode::Mode2);
+        $instance->add($offset, $data);
+        $this->assertSame($instance[$offset], $data, message: 'Data is not same #1');
+        $this->assertSame($instance->offsetGet($offset), $data, message: 'Data is not same #2');
+        $this->assertNotNull($instance[$offset], message: 'Data is not same #3');
+        $this->assertNotNull($instance->offsetGet($offset), message: 'Data is not same #4');
+    }
+
+    public function testOffsetSet(): void
+    {
+        $offset = crc32(time());
+        $data = sha1(time());
+
+        $instance = new ErrorsCollection(ParamsMode::Mode2);
+        $instance->add($offset, $data);
+
+        $ndata = md5(time());
+        $instance[$offset] = $ndata;
+        $this->assertSame($instance[$offset], $ndata, message: 'Changed data is not same as readed one #1');
+
+        $ndata = soundex($ndata);
+        $instance->offsetSet($offset, $ndata);
+        $this->assertSame($instance[$offset], $ndata, message: 'Changed data is not same as readed one #2');
+
+        $offset = md5(microtime(true));
+
+        $ndata = metaphone($ndata);
+        $instance[$offset] = $ndata;
+        $this->assertSame($instance[$offset], $ndata, message: 'Changed data is not same as readed one #3');
+
+        $ndata = soundex($ndata);
+        $instance->offsetSet($offset, $ndata);
+        $this->assertSame($instance[$offset], $ndata, message: 'Changed data is not same as readed one #4');
+    }
+
+    public function testOffsetUnset(): void
+    {
+        $offset = crc32(time());
+
+        $instance = new ErrorsCollection(ParamsMode::Mode2);
+
+        $this->expectException(UnsetErrorException::class);
+        $instance->offsetUnset($offset);
+    }
+
+    public function testIsEmpty(): void
+    {
+        $instance = new ErrorsCollection();
+        $this->assertTrue($instance->isEmpty(), message: 'Is not empty after creation');
+
+        $instance->add(crc32(time()));
+        $this->assertNotTrue($instance->isEmpty(), message: 'Is still empty after one element was added');
+    }
+
+    public function testClear(): void
+    {
+        $instance = new ErrorsCollection();
+        $instance->add(crc32(time()));
+        $instance->clear();
+        $this->assertEmpty($instance, message: 'Clear() must clear');
+    }
+
+    public function testStringConversion(): void
+    {
+        $instance = new ErrorsCollection();
+
+        $this->assertEmpty(
+            (string)$instance,
+            message: 'Converted to string empty ErrorsCollection must be empty'
+        );
+        $this->assertEmpty(
+            $instance->getHtml(),
+            message: 'Converted to HTML empty ErrorsCollection must be empty'
+        );
+
+        $instance->add(crc32(time()));
+
+        $this->assertNotEmpty(
+            (string)$instance,
+            message: 'Converted to string not empty ErrorsCollection must be not empty'
+        );
+        $this->assertNotEmpty(
+            $instance->getHtml(),
+            message: 'Converted to HTML not empty ErrorsCollection must be not empty'
+        );
+
+        $this->assertIsString(
+            $instance->getHtml(),
+            message: 'getHTML must generate strings'
+        );
+    }
+
+    public function testCount(): void
+    {
+        $instance = new ErrorsCollection();
+        $this->assertCount(0, $instance, message: 'Count is not 0 when collection was just created');
+
+        $instance->add(crc32(time()));
+        $this->assertSame(1, $instance->count(), message: 'Count must be 1 after one element was added');
+
+        $this->assertCount(1, $instance, message: 'Count function doesn\'t work');
+    }
+
+    public static function provideTestAddData(): Generator
+    {
+        yield 'mode1' => [
+            'mode' => ParamsMode::Mode1,
+            'addParams' => [
+                md5(time())
+            ],
+            'expectedKey' => 0
+        ];
+
+        yield 'mode2asprefix' => [
+            'mode' => ParamsMode::Mode2AsPrefix,
+            'addParams' => [
+                md5(time())
+            ],
+            'expectedKey' => 0
+        ];
+
+        $key = crc32(time());
+        yield 'mode2' => [
+            'mode' => ParamsMode::Mode2,
+            'addParams' => [
+                $key,
+                md5(time())
+            ],
+            'expectedKey' => $key
+        ];
+    }
+
+    #[DataProvider('provideTestAddData')]
+    public function testAdd(ParamsMode $mode, array $addParams, int|string $expectedKey): void
+    {
+        $instance = new ErrorsCollection($mode);
+        call_user_func_array([$instance, 'add'], $addParams);
+        $this->assertArrayHasKey($expectedKey, $instance);
+    }
+
+    /**
+     * @throws JsonException
+     */
+    public function testSerialization(): void
+    {
+        $instance = new ErrorsCollection(ParamsMode::Mode2);
+
+        $instance->add(md5(time()), sha1(time()));
+        $instance->add(crc32(time()), soundex(time()));
+
+        $serialized = serialize($instance);
+        $unserialized = unserialize($serialized);
+        $this->assertInstanceOf(
+            ErrorsCollection::class,
+            $unserialized,
+            message: 'Unserialized data is not ErrorsCollection class type but it should be #1'
+        );
+        $this->assertSame(
+            $instance->mode,
+            $unserialized->mode,
+            message: 'Serialization-unserialization fails #1'
+        );
+        $this->assertSame(
+            $instance->toArray(),
+            $unserialized->toArray(),
+            message: 'Serialization-unserialization fails #2'
+        );
+
+        $this->assertIsArray($instance->toArray(), message: 'toArray doesn\'t makes an array');
+        $this->assertIsString($instance->toJson(), message: 'toJSON doesn\'t makes a string');
+    }
+
+    public static function provideConstructorParams(): Generator
+    {
+        foreach (ParamsMode::cases() as $mode) {
+            yield $mode->name => [
+                'mode' => $mode,
+            ];
+        }
+    }
+}
diff --git a/tests/ErrorsTraitTest.php b/tests/ErrorsTraitTest.php
index 4f6a11c..f4c3f85 100644
--- a/tests/ErrorsTraitTest.php
+++ b/tests/ErrorsTraitTest.php
@@ -7,39 +7,37 @@
 
 class ErrorsTraitTest extends TestCase
 {
+    private function createFakeInstance(): object
+    {
+        return new class {
+            use ErrorsTrait;
+        };
+    }
 
-	private function createFakeInstance(): object
-	{
-		return new class {
-			use ErrorsTrait;
-		};
-	}
+    public function testGetErrors(): void
+    {
+        $mock = $this->createFakeInstance();
 
-	public function testGetErrors(): void
-	{
-		$mock = $this->createFakeInstance();
+        $this->assertIsArray($mock->getErrors(false));
+        $this->assertIsString($mock->getErrors(true));
+    }
 
-		$this->assertIsArray($mock->getErrors(false));
-		$this->assertIsString($mock->getErrors(true));
-	}
+    public function testGetHtmlErrors(): void
+    {
+        $mock = $this->createFakeInstance();
 
-	public function testGetHtmlErrors(): void
-	{
-		$mock = $this->createFakeInstance();
+        $this->assertIsString($mock->getHtmlErrors());
+    }
 
-		$this->assertIsString($mock->getHtmlErrors());
-	}
+    public function testHasAndSetError(): void
+    {
+        $mock = $this->createFakeInstance();
 
-	public function testHasAndSetError(): void
-	{
-		$mock = $this->createFakeInstance();
+        $this->assertIsBool($mock->hasError());
 
-		$this->assertIsBool($mock->hasError());
+        $this->assertFalse($mock->hasError());
 
-		$this->assertFalse($mock->hasError());
-
-		$mock->setErrors("some errors");
-		$this->assertTrue($mock->hasError());
-	}
-
-}
\ No newline at end of file
+        $mock->setErrors("some errors");
+        $this->assertTrue($mock->hasError());
+    }
+}