diff --git a/docs/index.md b/docs/index.md
index cb4cd04..3fcb75c 100644
--- a/docs/index.md
+++ b/docs/index.md
@@ -5,12 +5,14 @@ permalink: /index.html
 ---
 ## {{ page.title }}
 
-*Verja* is a very simple and stupid library to filter and validate input data. The name *Verja* comes from the Old
-Norse language and means defender. The idea behind this name is that the library defends you from invalid input.
+**Verja** is a very simple and stupid library to filter and validate input data. The name 
+[**Verja**](https://en.wiktionary.org/wiki/verja) (pronunciation **/ˈvɛrja/** 
+[IPA](https://en.wiktionary.org/wiki/Wiktionary:International_Phonetic_Alphabet)) comes from the Old Norse language and
+means to defend. The idea behind this name is that the library defends you from invalid, missing and unwanted input.
 
-The interface is very straight forward. `Verja\Gate` is the main object (you should **not reuse** this object). It
-holds the data that should be validated, and the `Verja\Field`s. Each field has it's own filters and validators. When
-you run `$container->validate()` each field gets filtered and validated.
+The interface is very straight forward. `Verja\Gate` is the gate for your input data. It holds the data that should be
+validated, and the `Verja\Field`s. Each field has it's own filters and validators. When you run `$container->validate()`
+each field gets filtered and validated.
 
 Here is a small pseudo code example to explain the simplicity of this library:
 
diff --git a/docs/usage.md b/docs/usage.md
index e2881da..40524f4 100644
--- a/docs/usage.md
+++ b/docs/usage.md
@@ -163,16 +163,8 @@ $gate->getData(); // throws "Invalid pw: value should be equal to contexts pw_co
 
 ### Show Errors
 
-The `Validator` may contain an error in the following format after validating an invalid value: 
-
-```php?start_inline=true
-return [
-    'key' => 'NOT_CONTAINS', // a key that can be used for translation
-    'value' => 'any string', // the value that got validated
-    'message' => 'value should contain "bar"', // OPTIONAL - a default error message (used for exceptions)
-    'parameters' => [ 'subString' => 'bar' ], // OPTIONAL - parameters used for validation
-];
-```
+The `Validator` may contain an `Verja\Error` after validating an invalid value that you can retrieve with
+`Validator::getError()`.
 
 The `Field` contains an array of all errors occurred during `Field::validate()` and the `Gate` contains an array with
 all arrays of errors from the fields. The method `Gate::getErrors()` may return something like this:
@@ -180,28 +172,65 @@ all arrays of errors from the fields. The method `Gate::getErrors()` may return
 ```php?start_inline=true
 return [
     'foo' => [
-        [
-           'key' => 'NOT_CONTAINS',
-           'value' => 'any string',
-           'message' => 'value should contain "bar"',
-           'parameters' => [ 'subString' => 'bar' ],
-        ]
+        new \Verja\Error(
+            'NOT_CONTAINS',
+            'any string',
+            'value should contain "bar"',
+            [ 'subString' => 'bar' ]
+        )
     ],
     'pw' => [
-        [
-            'key' => 'STRLEN_TOO_SHORT',
-            'value' => 'abc123',
-            'message' => 'value should be at least 8 characters long',
-            'parameters' => [ 'min' => 8, 'max' => 0 ],
-        ],
-        [
-            'key' => 'NOT_EQUAL',
-            'value' => 'abc123',
-            'message' => 'value should be equal to contexts pw_conf',
-            'parameters' => [ 'opposite' => 'pw_conf', 'jsonEncode' => true ]
-        ]
+        new \Verja\Error(
+            'STRLEN_TOO_SHORT',
+            'abc123',
+            'value should be at least 8 characters long',
+            [ 'min' => 8, 'max' => 0 ]
+        ),
+        new \Verja\Error(
+            'NOT_EQUAL',
+            'abc123',
+            'value should be equal to contexts pw_conf',
+            [ 'opposite' => 'pw_conf', 'jsonEncode' => true ]
+        )
     ],
 ];
+```
+
+You can then serialize this data to this json:
+
+```json
+{
+   "foo": [
+       {
+           "key": "NOT_CONTAINS",
+           "message": "value should contain \"bar\"",
+           "parameters": {
+               "subString": "bar",
+               "value": "any string"
+           }
+       }
+   ],
+   "pw": [
+       {
+           "key": "STRLEN_TOO_SHORT",
+           "message": "value should be at least 8 characters long",
+           "parameters": {
+               "min": 8,
+               "max": 0,
+               "value": "abc123"
+           }
+       },
+       {
+           "key": "NOT_EQUAL",
+           "message": "value should be equal to contexts pw_conf",
+           "parameters": {
+               "opposite": "pw_conf",
+               "jsonEncode": true,
+               "value": "abc123"
+           }
+       }
+   ]
+}
 ``` 
 
 ### Example
diff --git a/src/Error.php b/src/Error.php
new file mode 100644
index 0000000..54e7bac
--- /dev/null
+++ b/src/Error.php
@@ -0,0 +1,39 @@
+<?php
+
+namespace Verja;
+
+class Error
+{
+    /** @var string */
+    public $key;
+
+    /** @var  string */
+    public $message;
+
+    /** @var array */
+    public $parameters;
+
+    /**
+     * Error constructor.
+     *
+     * @param string $key
+     * @param mixed  $value
+     * @param string $message
+     * @param array  $parameters
+     */
+    public function __construct(string $key, $value, string $message = null, array $parameters = null)
+    {
+        $this->key   = $key;
+
+        if ($message !== null) {
+            $this->message = $message;
+        } else {
+            $this->message = sprintf('%s %s', json_encode($value), $key);
+        }
+
+        if ($parameters !== null) {
+            $this->parameters = $parameters;
+        }
+        $this->parameters['value'] = $value;
+    }
+}
diff --git a/src/Validator.php b/src/Validator.php
index 49b3832..190f6bf 100644
--- a/src/Validator.php
+++ b/src/Validator.php
@@ -88,31 +88,4 @@ public function getInverseError($value)
     {
         return null;
     }
-
-    /**
-     * @param string      $key
-     * @param mixed       $value
-     * @param string|null $message
-     * @param array|null  $parameters
-     * @return array
-     */
-    public static function buildError(string $key, $value, string $message = null, array $parameters = null)
-    {
-        $error = [
-            'key' => $key,
-            'value' => $value,
-        ];
-
-        if ($parameters !== null) {
-            $error['parameters'] = $parameters;
-        }
-
-        if ($message !== null) {
-            $error['message'] = $message;
-        } else {
-            $error['message'] = sprintf('%s %s', json_encode($value), $key);
-        }
-
-        return $error;
-    }
 }
diff --git a/src/Validator/Callback.php b/src/Validator/Callback.php
index e5b789b..5ee4e7b 100644
--- a/src/Validator/Callback.php
+++ b/src/Validator/Callback.php
@@ -2,6 +2,7 @@
 
 namespace Verja\Validator;
 
+use Verja\Error;
 use Verja\Validator;
 
 class Callback extends Validator
@@ -24,7 +25,7 @@ public function validate($value, array $context = []): bool
     {
         $result = call_user_func($this->callback, $value, $context);
 
-        if (is_array($result) && isset($result['key']) && isset($result['value']) && isset($result['message'])) {
+        if ($result instanceof Error) {
             $this->error = $result;
             return false;
         }
diff --git a/src/Validator/Contains.php b/src/Validator/Contains.php
index 7ad7e00..9062f8d 100644
--- a/src/Validator/Contains.php
+++ b/src/Validator/Contains.php
@@ -2,6 +2,7 @@
 
 namespace Verja\Validator;
 
+use Verja\Error;
 use Verja\Validator;
 
 class Contains extends Validator
@@ -23,7 +24,7 @@ public function __construct(string $subString)
     public function validate($value, array $context = []): bool
     {
         if (strpos($value, $this->subString) === false) {
-            $this->error = $this->buildError(
+            $this->error = new Error(
                 'NOT_CONTAINS',
                 $value,
                 sprintf('value should contain "%s"', $this->subString),
@@ -38,7 +39,7 @@ public function validate($value, array $context = []): bool
     /** {@inheritdoc} */
     public function getInverseError($value)
     {
-        return $this->buildError(
+        return new Error(
             'CONTAINS',
             $value,
             sprintf('value should not contain "%s"', $this->subString),
diff --git a/src/Validator/EmailAddress.php b/src/Validator/EmailAddress.php
index 983fd0f..614246b 100644
--- a/src/Validator/EmailAddress.php
+++ b/src/Validator/EmailAddress.php
@@ -2,6 +2,7 @@
 
 namespace Verja\Validator;
 
+use Verja\Error;
 use Verja\Validator;
 
 class EmailAddress extends Validator
@@ -13,7 +14,7 @@ class EmailAddress extends Validator
     public function validate($value, array $context = []): bool
     {
         if (!preg_match('/^' . self::LOCAL_PART_PATTERN . '@' . self::DOMAIN_PART_PATTERN . '$/', $value)) {
-            $this->error = $this::buildError(
+            $this->error = new Error(
                 'NO_EMAIL_ADDRESS',
                 $value,
                 'value should be a valid email address',
@@ -28,7 +29,7 @@ public function validate($value, array $context = []): bool
     /** {@inheritdoc} */
     public function getInverseError($value)
     {
-        return $this::buildError(
+        return new Error(
             'EMAIL_ADDRESS',
             $value,
             'value should not be an email address',
diff --git a/src/Validator/Equals.php b/src/Validator/Equals.php
index e242a97..06c6c64 100644
--- a/src/Validator/Equals.php
+++ b/src/Validator/Equals.php
@@ -2,6 +2,7 @@
 
 namespace Verja\Validator;
 
+use Verja\Error;
 use Verja\Validator;
 
 class Equals extends Validator
@@ -43,7 +44,7 @@ public function validate($value, array $context = []): bool
             }
         }
 
-        $this->error = $this->buildError(
+        $this->error = new Error(
             'NOT_EQUAL',
             $value,
             sprintf('value should be equal to contexts %s', $this->opposite),
@@ -55,7 +56,7 @@ public function validate($value, array $context = []): bool
     /** {@inheritdoc} */
     public function getInverseError($value)
     {
-        return $this->buildError(
+        return new Error(
             'EQUALS',
             $value,
             sprintf('value should not be equal to contexts %s', $this->opposite),
diff --git a/src/Validator/NotEmpty.php b/src/Validator/NotEmpty.php
index cd148f5..62e3323 100644
--- a/src/Validator/NotEmpty.php
+++ b/src/Validator/NotEmpty.php
@@ -2,6 +2,7 @@
 
 namespace Verja\Validator;
 
+use Verja\Error;
 use Verja\Validator;
 
 class NotEmpty extends Validator
@@ -10,7 +11,7 @@ class NotEmpty extends Validator
     public function validate($value, array $context = []): bool
     {
         if (empty($value)) {
-            $this->error = $this->buildError(
+            $this->error = new Error(
                 'IS_EMPTY',
                 $value,
                 'value should not be empty'
@@ -24,7 +25,7 @@ public function validate($value, array $context = []): bool
     /** {@inheritdoc} */
     public function getInverseError($value)
     {
-        return $this->buildError(
+        return new Error(
             'IS_NOT_EMPTY',
             $value,
             'value should be empty'
diff --git a/src/Validator/PregMatch.php b/src/Validator/PregMatch.php
index fe1a8e7..75cacd1 100644
--- a/src/Validator/PregMatch.php
+++ b/src/Validator/PregMatch.php
@@ -2,6 +2,7 @@
 
 namespace Verja\Validator;
 
+use Verja\Error;
 use Verja\Validator;
 
 class PregMatch extends Validator
@@ -26,7 +27,7 @@ public function validate($value, array $context = []): bool
             return true;
         }
 
-        $this->error = $this->buildError(
+        $this->error = new Error(
             'NO_MATCH',
             $value,
             sprintf('value should match "%s"', $this->pattern),
@@ -38,7 +39,7 @@ public function validate($value, array $context = []): bool
     /** {@inheritdoc} */
     public function getInverseError($value)
     {
-        return $this->buildError(
+        return new Error(
             'MATCHES',
             $value,
             sprintf('value should not match "%s"', $this->pattern),
diff --git a/src/Validator/StrLen.php b/src/Validator/StrLen.php
index 33b8c4c..4181c7c 100644
--- a/src/Validator/StrLen.php
+++ b/src/Validator/StrLen.php
@@ -2,6 +2,7 @@
 
 namespace Verja\Validator;
 
+use Verja\Error;
 use Verja\Validator;
 
 class StrLen extends Validator
@@ -30,7 +31,7 @@ public function validate($value, array $context = []): bool
     {
         $strLen = strlen($value);
         if ($strLen < $this->min) {
-            $this->error = $this->buildError(
+            $this->error = new Error(
                 'STRLEN_TOO_SHORT',
                 $value,
                 sprintf('value should be at least %d characters long', $this->min),
@@ -38,7 +39,7 @@ public function validate($value, array $context = []): bool
             );
             return false;
         } elseif ($this->max > 0 && $strLen > $this->max) {
-            $this->error = $this->buildError(
+            $this->error = new Error(
                 'STRLEN_TOO_LONG',
                 $value,
                 sprintf('value should be maximal %d characters long', $this->max),
diff --git a/test.php b/test.php
new file mode 100644
index 0000000..a72ef8f
--- /dev/null
+++ b/test.php
@@ -0,0 +1,43 @@
+<?php
+
+use Verja\Field;
+use Verja\Gate;
+use DependencyInjector\DI;
+use Verja\Validator as vv;
+
+require_once 'vendor/autoload.php';
+
+// we using tflori/dependency-injector here...
+DI::set(
+    'verja',                     // namne
+    function () {                // factory
+        return new Gate();
+    },
+    false                        // share / singleton
+);
+
+// this is the controller
+function controller()
+{
+    /** @var Gate $verja */
+    $verja = DI::get('verja');
+    $field1 = new DField();
+    $field2 = new DField();
+    $validator = new vv\NotEmpty();
+
+    $field1->addValidator($validator);
+    $field2->addValidator($validator);
+
+    var_dump($field1->getValidators());
+    var_dump($field2->getValidators());
+}
+
+class DField extends Field
+{
+    public function getValidators()
+    {
+        return $this->validators;
+    }
+}
+
+controller();
diff --git a/tests/ErrorsTest.php b/tests/ErrorsTest.php
index 8cf16f1..35f5252 100644
--- a/tests/ErrorsTest.php
+++ b/tests/ErrorsTest.php
@@ -2,6 +2,7 @@
 
 namespace Verja\Test;
 
+use Verja\Error;
 use Verja\Field;
 use Verja\Gate;
 use Verja\Test\Examples\CustomValidator\GeneratedMessage;
@@ -36,17 +37,39 @@ public function fieldCallsGetErrorWhenInvalid()
     }
 
     /** @test */
-    public function buildErrorGeneratesMessage()
+    public function errorsCanBeSerialized()
     {
-        $validator = new GeneratedMessage();
-        $validator->validate('value');
+        $error = new Error('ERROR_KEY', 'validated value', 'Error message from validator');
 
-        $result = $validator->getError();
+        $serialized = serialize($error);
 
-        self::assertSame([
-            'key' => 'GENERATED_MESSAGE',
-            'value' => 'value',
-            'message' => '"value" GENERATED_MESSAGE'
-        ], $result);
+        self::assertContains('ERROR_KEY', $serialized);
+        self::assertContains('validated value', $serialized);
+        self::assertContains('Error message from validator', $serialized);
+    }
+
+    /** @test */
+    public function errorsCanBeUnserialized()
+    {
+        $error = new Error('ERROR_KEY', 'validated value', 'Error message from validator');
+        $serialized = serialize($error);
+
+        $result = unserialize($serialized);
+
+        self::assertEquals($error, $result);
+    }
+
+    /** @test */
+    public function errorsCanBeJsonEncoded()
+    {
+        $error = new Error('ERROR_KEY', 'validated value', 'Error message from validator');
+
+        $json = json_encode($error);
+
+        self::assertSame(json_encode([
+            'key' => 'ERROR_KEY',
+            'message' => 'Error message from validator',
+            'parameters' => ['value' => 'validated value'],
+        ]), $json);
     }
 }
diff --git a/tests/Examples/CustomValidator/GeneratedMessage.php b/tests/Examples/CustomValidator/GeneratedMessage.php
deleted file mode 100644
index 6be8479..0000000
--- a/tests/Examples/CustomValidator/GeneratedMessage.php
+++ /dev/null
@@ -1,14 +0,0 @@
-<?php
-
-namespace Verja\Test\Examples\CustomValidator;
-
-use Verja\Validator;
-
-class GeneratedMessage extends Validator
-{
-    public function validate($value, array $context = []): bool
-    {
-        $this->error = $this->buildError('GENERATED_MESSAGE', $value);
-        return false;
-    }
-}
diff --git a/tests/Validator/CallbackTest.php b/tests/Validator/CallbackTest.php
index 27b313b..65a04ed 100644
--- a/tests/Validator/CallbackTest.php
+++ b/tests/Validator/CallbackTest.php
@@ -2,8 +2,8 @@
 
 namespace Verja\Test\Validator;
 
+use Verja\Error;
 use Verja\Test\TestCase;
-use Verja\Validator;
 use Verja\Validator\Callback;
 
 class CallbackTest extends TestCase
@@ -28,16 +28,12 @@ public function callsCallbackToValidate()
     public function usesArrayReturnValueAsError()
     {
         $validator = new Callback(function ($value) {
-            return Validator::buildError('KEY', $value);
+            return new Error('KEY', $value);
         });
 
         $validator->validate('value');
 
-        self::assertSame([
-            'key' => 'KEY',
-            'value' => 'value',
-            'message' => '"value" KEY'
-        ], $validator->getError());
+        self::assertEquals(new Error('KEY', 'value', '"value" KEY'), $validator->getError());
     }
 
     /** @test */
diff --git a/tests/Validator/ContainsTest.php b/tests/Validator/ContainsTest.php
index 7e74f58..dba3b52 100644
--- a/tests/Validator/ContainsTest.php
+++ b/tests/Validator/ContainsTest.php
@@ -2,6 +2,7 @@
 
 namespace Verja\Test\Validator;
 
+use Verja\Error;
 use Verja\Test\TestCase;
 use Verja\Validator\Contains;
 
@@ -37,12 +38,10 @@ public function returnsFalseForNotContainedStrings()
         $result = $validator->validate('noSpaces');
 
         self::assertFalse($result);
-        self::assertSame([
-            'key' => 'NOT_CONTAINS',
-            'value' => 'noSpaces',
-            'parameters' => ['subString' => ' '],
-            'message' => 'value should contain " "'
-        ], $validator->getError());
+        self::assertEquals(
+            new Error('NOT_CONTAINS', 'noSpaces', 'value should contain " "', ['subString' => ' ']),
+            $validator->getError()
+        );
     }
 
     public function provideNotContainedStrings()
@@ -59,11 +58,9 @@ public function returnsContainsError()
 
         $result = $validator->getInverseError('with space');
 
-        self::assertSame([
-            'key' => 'CONTAINS',
-            'value' => 'with space',
-            'parameters' => ['subString' => ' '],
-            'message' => 'value should not contain " "'
-        ], $result);
+        self::assertEquals(
+            new Error('CONTAINS', 'with space', 'value should not contain " "', ['subString' => ' ']),
+            $result
+        );
     }
 }
diff --git a/tests/Validator/EmailAddressTest.php b/tests/Validator/EmailAddressTest.php
index ccd8aa5..147e1dd 100644
--- a/tests/Validator/EmailAddressTest.php
+++ b/tests/Validator/EmailAddressTest.php
@@ -2,6 +2,7 @@
 
 namespace Verja\Test\Validator;
 
+use Verja\Error;
 use Verja\Test\TestCase;
 use Verja\Validator\EmailAddress;
 
@@ -39,11 +40,10 @@ public function setsError()
         $validator = new EmailAddress();
 
         self::assertFalse($validator->validate('@'));
-        self::assertSame([
-            'key' => 'NO_EMAIL_ADDRESS',
-            'value' => '@',
-            'message' => 'value should be a valid email address',
-        ], $validator->getError());
+        self::assertEquals(
+            new Error('NO_EMAIL_ADDRESS', '@', 'value should be a valid email address'),
+            $validator->getError()
+        );
     }
 
     /** @test */
@@ -51,10 +51,9 @@ public function returnsInverseError()
     {
         $validator = new EmailAddress();
 
-        self::assertSame([
-            'key' => 'EMAIL_ADDRESS',
-            'value' => 'john.doe@example.com',
-            'message' => 'value should not be an email address'
-        ], $validator->getInverseError('john.doe@example.com'));
+        self::assertEquals(
+            new Error('EMAIL_ADDRESS', 'john.doe@example.com', 'value should not be an email address'),
+            $validator->getInverseError('john.doe@example.com')
+        );
     }
 }
diff --git a/tests/Validator/EqualsTest.php b/tests/Validator/EqualsTest.php
index 38470ea..20948a3 100644
--- a/tests/Validator/EqualsTest.php
+++ b/tests/Validator/EqualsTest.php
@@ -2,6 +2,7 @@
 
 namespace Verja\Test\Validator;
 
+use Verja\Error;
 use Verja\Test\TestCase;
 use Verja\Validator\Equals;
 
@@ -62,12 +63,15 @@ public function jsonEncodingCanBeDisabled()
         $result = $validator->validate(['foo' => 'bar'], ['opposite' => (object) ['foo' => 'bar']]);
 
         self::assertFalse($result);
-        self::assertSame([
-            'key' => 'NOT_EQUAL',
-            'value' => ['foo' => 'bar'],
-            'parameters' => ['opposite' => 'opposite', 'jsonEncode' => false],
-            'message' => 'value should be equal to contexts opposite'
-        ], $validator->getError());
+        self::assertEquals(
+            new Error(
+                'NOT_EQUAL',
+                ['foo' => 'bar'],
+                'value should be equal to contexts opposite',
+                ['opposite' => 'opposite', 'jsonEncode' => false]
+            ),
+            $validator->getError()
+        );
     }
 
     /** @test */
@@ -77,11 +81,14 @@ public function returnsInverseError()
 
         $result = $validator->getInverseError('value');
 
-        self::assertSame([
-            'key' => 'EQUALS',
-            'value' => 'value',
-            'parameters' => ['opposite' => 'opposite', 'jsonEncode' => true],
-            'message' => 'value should not be equal to contexts opposite'
-        ], $result);
+        self::assertEquals(
+            new Error(
+                'EQUALS',
+                'value',
+                'value should not be equal to contexts opposite',
+                ['opposite' => 'opposite', 'jsonEncode' => true]
+            ),
+            $result
+        );
     }
 }
diff --git a/tests/Validator/NotEmptyTest.php b/tests/Validator/NotEmptyTest.php
index d057298..50f5911 100644
--- a/tests/Validator/NotEmptyTest.php
+++ b/tests/Validator/NotEmptyTest.php
@@ -2,6 +2,7 @@
 
 namespace Verja\Test\Validator;
 
+use Verja\Error;
 use Verja\Test\TestCase;
 use Verja\Validator\NotEmpty;
 
@@ -63,11 +64,10 @@ public function setsNotEmptyError()
 
         $result = $validator->getError();
 
-        self::assertSame([
-            'key' => 'IS_EMPTY',
-            'value' => 0,
-            'message' => 'value should not be empty'
-        ], $result);
+        self::assertEquals(
+            new Error('IS_EMPTY', 0, 'value should not be empty'),
+            $result
+        );
     }
 
     /** @test */
@@ -77,10 +77,9 @@ public function returnsInverseError()
 
         $result = $validator->getInverseError('value');
 
-        self::assertSame([
-            'key' => 'IS_NOT_EMPTY',
-            'value' => 'value',
-            'message' => 'value should be empty'
-        ], $result);
+        self::assertEquals(
+            new Error('IS_NOT_EMPTY', 'value', 'value should be empty'),
+            $result
+        );
     }
 }
diff --git a/tests/Validator/PregMatchTest.php b/tests/Validator/PregMatchTest.php
index be50bf7..f4355d9 100644
--- a/tests/Validator/PregMatchTest.php
+++ b/tests/Validator/PregMatchTest.php
@@ -2,6 +2,7 @@
 
 namespace Verja\Test\Validator;
 
+use Verja\Error;
 use Verja\Test\TestCase;
 use Verja\Validator\PregMatch;
 
@@ -25,12 +26,10 @@ public function setsError()
         $result = $validator->validate('bar');
 
         self::assertFalse($result);
-        self::assertSame([
-            'key' => 'NO_MATCH',
-            'value' => 'bar',
-            'parameters' => ['pattern' => '#foo#'],
-            'message' => 'value should match "#foo#"'
-        ], $validator->getError());
+        self::assertEquals(
+            new Error('NO_MATCH', 'bar', 'value should match "#foo#"', ['pattern' => '#foo#']),
+            $validator->getError()
+        );
     }
 
     /** @test */
@@ -38,11 +37,9 @@ public function returnsInverseError()
     {
         $validator = new PregMatch('#foo#');
 
-        self::assertSame([
-            'key' => 'MATCHES',
-            'value' => 'some foo for you',
-            'parameters' => ['pattern' => '#foo#'],
-            'message' => 'value should not match "#foo#"'
-        ], $validator->getInverseError('some foo for you'));
+        self::assertEquals(
+            new Error('MATCHES', 'some foo for you', 'value should not match "#foo#"', ['pattern' => '#foo#']),
+            $validator->getInverseError('some foo for you')
+        );
     }
 }
diff --git a/tests/Validator/StrLenTest.php b/tests/Validator/StrLenTest.php
index e433f54..a8fbaef 100644
--- a/tests/Validator/StrLenTest.php
+++ b/tests/Validator/StrLenTest.php
@@ -2,6 +2,7 @@
 
 namespace Verja\Test\Validator;
 
+use Verja\Error;
 use Verja\Test\TestCase;
 use Verja\Validator\StrLen;
 
@@ -33,12 +34,10 @@ public function limitsLengthTest()
         $result = $validator->validate('long');
 
         self::assertFalse($result);
-        self::assertSame([
-            'key' => 'STRLEN_TOO_LONG',
-            'value' => 'long',
-            'parameters' => ['min' => 0, 'max' => 2],
-            'message' => 'value should be maximal 2 characters long'
-        ], $validator->getError());
+        self::assertEquals(
+            new Error('STRLEN_TOO_LONG', 'long', 'value should be maximal 2 characters long', ['min' => 0, 'max' => 2]),
+            $validator->getError()
+        );
     }
 
     /** @test */
@@ -49,12 +48,15 @@ public function requiresMinLength()
         $result = $validator->validate('short');
 
         self::assertFalse($result);
-        self::assertSame([
-            'key' => 'STRLEN_TOO_SHORT',
-            'value' => 'short',
-            'parameters' => ['min' => 6, 'max' => 0],
-            'message' => 'value should be at least 6 characters long'
-        ], $validator->getError());
+        self::assertEquals(
+            new Error(
+                'STRLEN_TOO_SHORT',
+                'short',
+                'value should be at least 6 characters long',
+                ['min' => 6, 'max' => 0]
+            ),
+            $validator->getError()
+        );
     }
 
     /** @test */