diff --git a/src/Model/Validator/ExtractedMethodValidator.php b/src/Model/Validator/ExtractedMethodValidator.php
index c1b8cc56..6a63b616 100644
--- a/src/Model/Validator/ExtractedMethodValidator.php
+++ b/src/Model/Validator/ExtractedMethodValidator.php
@@ -59,7 +59,7 @@ public function __construct(
             public function getCode(): string
             {
                 $renderHelper = new RenderHelper($this->generatorConfiguration);
-                return "private function {$this->validator->getExtractedMethodName()}(&\$value): void {
+                return "private function {$this->validator->getExtractedMethodName()}(&\$value, \$modelData): void {
                     {$this->validator->getValidatorSetUp()}
                     
                     if ({$this->validator->getCheck()}) {
diff --git a/src/Model/Validator/PropertyNamesValidator.php b/src/Model/Validator/PropertyNamesValidator.php
index 019655ff..e738e553 100644
--- a/src/Model/Validator/PropertyNamesValidator.php
+++ b/src/Model/Validator/PropertyNamesValidator.php
@@ -10,6 +10,7 @@
 use PHPModelGenerator\Model\Schema;
 use PHPModelGenerator\Model\SchemaDefinition\JsonSchema;
 use PHPModelGenerator\Model\Validator;
+use PHPModelGenerator\PropertyProcessor\Property\ConstProcessor;
 use PHPModelGenerator\PropertyProcessor\Property\StringProcessor;
 use PHPModelGenerator\PropertyProcessor\PropertyMetaDataCollection;
 use PHPModelGenerator\SchemaProcessor\SchemaProcessor;
@@ -38,7 +39,15 @@ public function __construct(
     ) {
         $this->isResolved = true;
 
-        $nameValidationProperty = (new StringProcessor(new PropertyMetaDataCollection(), $schemaProcessor, $schema))
+        $processor = array_key_exists('const', $propertiesNames->getJson())
+            ? ConstProcessor::class
+            : StringProcessor::class;
+
+        if ($processor === ConstProcessor::class && gettype($propertiesNames->getJson()['const']) !== 'string') {
+            throw new SchemaException("Invalid const property name in file {$propertiesNames->getFile()}");
+        }
+
+        $nameValidationProperty = (new $processor(new PropertyMetaDataCollection(), $schemaProcessor, $schema))
             ->process('property name', $propertiesNames)
             // the property name validator doesn't need type checks or required checks so simply filter them out
             ->filterValidators(static function (Validator $validator): bool {
diff --git a/src/PropertyProcessor/Property/AbstractPropertyProcessor.php b/src/PropertyProcessor/Property/AbstractPropertyProcessor.php
index e041c810..31984003 100644
--- a/src/PropertyProcessor/Property/AbstractPropertyProcessor.php
+++ b/src/PropertyProcessor/Property/AbstractPropertyProcessor.php
@@ -213,7 +213,9 @@ protected function addComposedValueValidator(PropertyInterface $property, JsonSc
                     $propertySchema->withJson([
                         'type' => $composedValueKeyword,
                         'propertySchema' => $propertySchema,
-                        'onlyForDefinedValues' => !($this instanceof BaseProcessor) && !$property->isRequired(),
+                        'onlyForDefinedValues' => !($this instanceof BaseProcessor) &&
+                            (!$property->isRequired()
+                                && $this->schemaProcessor->getGeneratorConfiguration()->isImplicitNullAllowed()),
                     ]),
                 );
 
diff --git a/src/PropertyProcessor/Property/ArrayProcessor.php b/src/PropertyProcessor/Property/ArrayProcessor.php
index 8937e2a0..0057fcbe 100644
--- a/src/PropertyProcessor/Property/ArrayProcessor.php
+++ b/src/PropertyProcessor/Property/ArrayProcessor.php
@@ -16,11 +16,13 @@
 use PHPModelGenerator\Model\Property\PropertyInterface;
 use PHPModelGenerator\Model\Property\PropertyType;
 use PHPModelGenerator\Model\SchemaDefinition\JsonSchema;
+use PHPModelGenerator\Model\Validator;
 use PHPModelGenerator\Model\Validator\AdditionalItemsValidator;
 use PHPModelGenerator\Model\Validator\ArrayItemValidator;
 use PHPModelGenerator\Model\Validator\ArrayTupleValidator;
 use PHPModelGenerator\Model\Validator\PropertyTemplateValidator;
 use PHPModelGenerator\Model\Validator\PropertyValidator;
+use PHPModelGenerator\Model\Validator\RequiredPropertyValidator;
 use PHPModelGenerator\PropertyProcessor\Decorator\Property\DefaultArrayToEmptyArrayDecorator;
 use PHPModelGenerator\PropertyProcessor\PropertyMetaDataCollection;
 use PHPModelGenerator\PropertyProcessor\PropertyFactory;
@@ -253,16 +255,21 @@ private function addContainsValidation(PropertyInterface $property, JsonSchema $
             return;
         }
 
+        $name = "item of array {$property->getName()}";
         // an item of the array behaves like a nested property to add item-level validation
         $nestedProperty = (new PropertyFactory(new PropertyProcessorFactory()))
             ->create(
-                new PropertyMetaDataCollection(),
+                new PropertyMetaDataCollection([$name]),
                 $this->schemaProcessor,
                 $this->schema,
-                "item of array {$property->getName()}",
+                $name,
                 $propertySchema->withJson($propertySchema->getJson()[self::JSON_FIELD_CONTAINS]),
             );
 
+        $nestedProperty->filterValidators(static function (Validator $validator): bool {
+            return !is_a($validator->getValidator(), RequiredPropertyValidator::class);
+        });
+
         $property->addValidator(
             new PropertyTemplateValidator(
                 $property,
diff --git a/src/PropertyProcessor/Property/ConstProcessor.php b/src/PropertyProcessor/Property/ConstProcessor.php
index 9ca86d8e..d5ad8097 100644
--- a/src/PropertyProcessor/Property/ConstProcessor.php
+++ b/src/PropertyProcessor/Property/ConstProcessor.php
@@ -10,7 +10,7 @@
 use PHPModelGenerator\Model\Property\PropertyType;
 use PHPModelGenerator\Model\SchemaDefinition\JsonSchema;
 use PHPModelGenerator\Model\Validator\PropertyValidator;
-use PHPModelGenerator\PropertyProcessor\PropertyProcessorInterface;
+use PHPModelGenerator\Utils\RenderHelper;
 use PHPModelGenerator\Utils\TypeConverter;
 
 /**
@@ -18,7 +18,7 @@
  *
  * @package PHPModelGenerator\PropertyProcessor\Property
  */
-class ConstProcessor implements PropertyProcessorInterface
+class ConstProcessor extends AbstractPropertyProcessor
 {
     /**
      * @inheritdoc
@@ -34,13 +34,26 @@ public function process(string $propertyName, JsonSchema $propertySchema): Prope
             $json['description'] ?? '',
         );
 
-        return $property
-            ->setRequired(true)
-            ->addValidator(new PropertyValidator(
-                $property,
-                '$value !== ' . var_export($json['const'], true),
-                InvalidConstException::class,
-                [$json['const']],
-            ));
+        $property->setRequired($this->propertyMetaDataCollection->isAttributeRequired($propertyName));
+
+        $check = match(true) {
+            $property->isRequired()
+                => '$value !== ' . var_export($json['const'], true),
+            $this->isImplicitNullAllowed($property)
+                => '!in_array($value, ' . RenderHelper::varExportArray([$json['const'], null]) . ', true)',
+            default
+                => "array_key_exists('{$property->getName()}', \$modelData) && \$value !== " . var_export($json['const'], true),
+        };
+
+        $property->addValidator(new PropertyValidator(
+            $property,
+            $check,
+            InvalidConstException::class,
+            [$json['const']],
+        ));
+
+        $this->generateValidators($property, $propertySchema);
+
+        return $property;
     }
 }
diff --git a/src/Templates/Validator/AdditionalProperties.phptpl b/src/Templates/Validator/AdditionalProperties.phptpl
index 87557485..96c93e64 100644
--- a/src/Templates/Validator/AdditionalProperties.phptpl
+++ b/src/Templates/Validator/AdditionalProperties.phptpl
@@ -1,4 +1,4 @@
-(function () use ($properties, &$invalidProperties) {
+(function () use ($properties, &$invalidProperties, $modelData) {
     {% if generatorConfiguration.collectErrors() %}
         $originalErrorRegistry = $this->_errorRegistry;
     {% endif %}
diff --git a/src/Templates/Validator/ArrayItem.phptpl b/src/Templates/Validator/ArrayItem.phptpl
index 0c14f334..cdbea591 100644
--- a/src/Templates/Validator/ArrayItem.phptpl
+++ b/src/Templates/Validator/ArrayItem.phptpl
@@ -1,4 +1,4 @@
-is_array($value) && (function (&$items) use (&$invalidItems{{ suffix }}) {
+is_array($value) && (function (&$items) use (&$invalidItems{{ suffix }}, $modelData) {
     {% if generatorConfiguration.collectErrors() %}
         $originalErrorRegistry = $this->_errorRegistry;
     {% endif %}
diff --git a/src/Templates/Validator/ArrayTuple.phptpl b/src/Templates/Validator/ArrayTuple.phptpl
index 425e9d11..d6ce49ea 100644
--- a/src/Templates/Validator/ArrayTuple.phptpl
+++ b/src/Templates/Validator/ArrayTuple.phptpl
@@ -1,4 +1,4 @@
-is_array($value) && (function (&$items) use (&$invalidTuples) {
+is_array($value) && (function (&$items) use (&$invalidTuples, $modelData) {
     {% if generatorConfiguration.collectErrors() %}
         $originalErrorRegistry = $this->_errorRegistry;
     {% endif %}
diff --git a/src/Templates/Validator/PatternProperties.phptpl b/src/Templates/Validator/PatternProperties.phptpl
index b69d4c13..42bb0094 100644
--- a/src/Templates/Validator/PatternProperties.phptpl
+++ b/src/Templates/Validator/PatternProperties.phptpl
@@ -1,4 +1,4 @@
-(function () use ($properties, &$invalidProperties) {
+(function () use ($properties, &$invalidProperties, $modelData) {
     {% if generatorConfiguration.collectErrors() %}
         $originalErrorRegistry = $this->_errorRegistry;
     {% endif %}
diff --git a/src/Utils/RenderHelper.php b/src/Utils/RenderHelper.php
index 4d249350..c69daaad 100644
--- a/src/Utils/RenderHelper.php
+++ b/src/Utils/RenderHelper.php
@@ -182,7 +182,7 @@ public function renderValidator(PropertyValidatorInterface $validator, Schema $s
             $schema->addMethod($validator->getExtractedMethodName(), $validator->getMethod());
         }
 
-        return "\$this->{$validator->getExtractedMethodName()}(\$value);";
+        return "\$this->{$validator->getExtractedMethodName()}(\$value, \$modelData);";
     }
 
     public function renderMethods(Schema $schema): string
diff --git a/tests/Basic/PropertyNamesTest.php b/tests/Basic/PropertyNamesTest.php
index 692c641c..42dd90f3 100644
--- a/tests/Basic/PropertyNamesTest.php
+++ b/tests/Basic/PropertyNamesTest.php
@@ -4,6 +4,7 @@
 
 namespace PHPModelGenerator\Tests\Basic;
 
+use PHPModelGenerator\Exception\SchemaException;
 use PHPModelGenerator\Model\GeneratorConfiguration;
 use PHPModelGenerator\Tests\AbstractPHPModelGeneratorTestCase;
 
@@ -84,6 +85,12 @@ public function validPropertyNamesDataProvider(): array
                         'test1298398717931793179317937197931' => 2,
                     ],
                 ],
+                'const' => [
+                    '{"const": "test"}',
+                    [
+                        'test' => 1,
+                    ],
+                ],
             ],
         );
     }
@@ -166,6 +173,21 @@ public function invalidPropertyNamesDataProvider(): array
     * Value for property name doesn't match pattern ^test[0-9]+$
   - invalid property 'test'
     * Value for property name doesn't match pattern ^test[0-9]+$
+ERROR
+                ],
+                'const violation' => [
+                    '{"const": "test"}',
+                    [
+                        'test1' => 1,
+                        'test' => 2,
+                        'bla' => 3,
+                    ],
+                    <<<ERROR
+contains properties with invalid names.
+  - invalid property 'test1'
+    * Invalid value for property name declined by const constraint
+  - invalid property 'bla'
+    * Invalid value for property name declined by const constraint
 ERROR
                 ],
             ],
@@ -211,4 +233,12 @@ public function invalidCombinedPropertyNamesDataProvider(): array
             ],
         ];
     }
+
+    public function testInvalidConstPropertyNamesThrowsAnException(): void
+    {
+        $this->expectException(SchemaException::class);
+        $this->expectExceptionMessageMatches('/Invalid const property name in file/');
+
+        $this->generateClassFromFileTemplate('PropertyNames.json', ['{"const": false}'], escape: false);
+    }
 }
diff --git a/tests/Objects/ArrayPropertyTest.php b/tests/Objects/ArrayPropertyTest.php
index 4f855ccd..13c34c6e 100644
--- a/tests/Objects/ArrayPropertyTest.php
+++ b/tests/Objects/ArrayPropertyTest.php
@@ -683,7 +683,6 @@ public function validArrayContainsDataProvider(): array
         return $this->combineDataProvider(
             $this->validationMethodDataProvider(),
             [
-                'null' => [[3, null, true]],
                 'empty string' => [[3, '', true]],
                 'lowercase string' => [[3, 'abc', true]],
                 'uppercase string' => [[3, 'AB', true]],
diff --git a/tests/Objects/ConstPropertyTest.php b/tests/Objects/ConstPropertyTest.php
index 3f87ec06..4ed86647 100644
--- a/tests/Objects/ConstPropertyTest.php
+++ b/tests/Objects/ConstPropertyTest.php
@@ -4,10 +4,19 @@
 
 namespace PHPModelGenerator\Tests\Objects;
 
+use PHPModelGenerator\Exception\Arrays\ContainsException;
+use PHPModelGenerator\Exception\Arrays\InvalidItemException;
+use PHPModelGenerator\Exception\Arrays\InvalidTupleException;
+use PHPModelGenerator\Exception\ComposedValue\OneOfException;
+use PHPModelGenerator\Exception\ErrorRegistryException;
 use PHPModelGenerator\Exception\FileSystemException;
+use PHPModelGenerator\Exception\Object\InvalidAdditionalPropertiesException;
+use PHPModelGenerator\Exception\Object\InvalidPatternPropertiesException;
+use PHPModelGenerator\Exception\Object\RequiredValueException;
 use PHPModelGenerator\Exception\ValidationException;
 use PHPModelGenerator\Exception\RenderException;
 use PHPModelGenerator\Exception\SchemaException;
+use PHPModelGenerator\Model\GeneratorConfiguration;
 use PHPModelGenerator\Tests\AbstractPHPModelGeneratorTestCase;
 use stdClass;
 
@@ -34,18 +43,124 @@ public function testProvidedConstPropertyIsValid(): void
     }
 
     /**
-     * @throws FileSystemException
-     * @throws RenderException
-     * @throws SchemaException
+     * @dataProvider nestedConstStructureDataProvider
      */
-    public function testNotProvidedConstPropertyThrowsAnException(): void
+    public function testNotProvidedOptionalNestedConstPropertyIsValid(string $file): void
+    {
+        $className = $this->generateClassFromFile($file);
+
+        $object = new $className([]);
+
+        $this->assertNull($object->getProperty());
+    }
+
+    public function nestedConstStructureDataProvider(): array
+    {
+        return [
+            'array tuple' => ['ArrayTupleConstProperty.json'],
+            'array item'  => ['ArrayItemConstProperty.json'],
+            'oneOf'       => ['OneOfConstProperty.json'],
+        ];
+    }
+
+    /**
+     * @dataProvider validArrayConstValues
+     */
+    public function testProvidedArrayConstPropertyIsValid(string $file, ?array $value): void
+    {
+        $className = $this->generateClassFromFile($file);
+
+        $object = new $className(['property' => $value]);
+
+        $this->assertSame($value, $object->getProperty());
+    }
+
+    public function validArrayConstValues(): array
+    {
+        return $this->combineDataProvider(
+            [
+                'array tuple' => ['ArrayTupleConstProperty.json'],
+                'array item'  => ['ArrayItemConstProperty.json'],
+            ],
+            [
+                'item provided' => [['red']],
+                'multiple items provided' => [['red', 'red']],
+                'null provided' => [null],
+            ],
+        );
+    }
+
+    /**
+     * @dataProvider invalidArrayConstDataProvider
+     */
+    public function testNotMatchingArrayConstPropertyThrowsAnException(
+        string $file,
+        string $exception,
+        array $value,
+    ): void {
+        $this->expectException($exception);
+
+        $className = $this->generateClassFromFile($file);
+
+        new $className(['property' => $value]);
+    }
+
+    public function invalidArrayConstDataProvider(): array
+    {
+        return $this->combineDataProvider(
+            [
+                'array tuple' => ['ArrayTupleConstProperty.json', InvalidTupleException::class],
+                'array item'  => ['ArrayItemConstProperty.json', InvalidItemException::class],
+            ],
+            [
+                'invalid item'                  => [['green']],
+                'invalid item (multiple items)' => [['green', 'red']],
+                'null'                          => [[null]],
+            ],
+        );
+    }
+
+    /**
+     * @dataProvider nestedConstStructureDataProvider
+     */
+    public function testNullForNestedConstPropertyWithImplicitNullDisabledThrowsAnException(string $file): void
     {
         $this->expectException(ValidationException::class);
-        $this->expectExceptionMessage('Invalid value for stringProperty declined by const constraint');
 
-        $className = $this->generateClassFromFile('ConstProperty.json');
+        $className = $this->generateClassFromFile($file, implicitNull: false);
 
-        new $className([]);
+        new $className(['property' => null]);
+    }
+
+    /**
+     * @dataProvider validOneOfDataProvider
+     */
+    public function testProvidedOneOfConstPropertyIsValid(mixed $propertyValue): void
+    {
+        $className = $this->generateClassFromFile('OneOfConstProperty.json');
+
+        $object = new $className(['property' => $propertyValue]);
+
+        $this->assertSame($propertyValue, $object->getProperty());
+    }
+
+    public function validOneOfDataProvider(): array
+    {
+        return [
+            'first branch'  => ['red'],
+            'second branch' => [1],
+            'implicit null' => [null],
+        ];
+    }
+
+    public function testNotMatchingOneOfPropertyThrowsAnException(): void
+    {
+        $this->expectException(OneOfException::class);
+        $this->expectExceptionMessage('Invalid value for property declined by composition constraint');
+
+        $className = $this->generateClassFromFile('OneOfConstProperty.json');
+
+        new $className(['property' => 'green']);
     }
 
     /**
@@ -62,7 +177,7 @@ public function testNotMatchingProvidedDataThrowsAnException($propertyValue): vo
         $this->expectException(ValidationException::class);
         $this->expectExceptionMessage('Invalid value for stringProperty declined by const constraint');
 
-        $className = $this->generateClassFromFile('ConstProperty.json');
+        $className = $this->generateClassFromFile('ConstProperty.json', null, false, false);
 
         new $className(['stringProperty' => $propertyValue]);
     }
@@ -79,4 +194,289 @@ public function invalidPropertyDataProvider(): array
             'null' => [null],
         ];
     }
+
+    /**
+     * @throws FileSystemException
+     * @throws RenderException
+     * @throws SchemaException
+     */
+    public function testProvidedConstOnlyRequiredPropertyIsValid(): void
+    {
+        $className = $this->generateClassFromFile('RequiredAndOptionalConstProperties.json');
+
+        $object = new $className(['requiredProperty' => 'red']);
+
+        $this->assertSame('red', $object->getRequiredProperty());
+        $this->assertNull($object->getOptionalProperty());
+    }
+
+    /**
+     * @throws FileSystemException
+     * @throws RenderException
+     * @throws SchemaException
+     */
+    public function testProvidedNullOptionalPropertyConstPropertyIsValid(): void
+    {
+        $className = $this->generateClassFromFile('RequiredAndOptionalConstProperties.json');
+
+        $object = new $className(['requiredProperty' => 'red', 'optionalProperty' => null]);
+
+        $this->assertSame('red', $object->getRequiredProperty());
+        $this->assertNull($object->getOptionalProperty());
+    }
+
+    /**
+     * @dataProvider requiredAndOptionalPropertiesDataProvider
+     *
+     * @throws FileSystemException
+     * @throws RenderException
+     * @throws SchemaException
+     */
+    public function testProvidedConstPropertiesIsValidWithDifferentImplicitNull(
+        bool $implicitNull,
+        string $reqPropertyValue,
+        string $optPropertyValue
+    ): void {
+        $className = $this->generateClassFromFile(
+            'RequiredAndOptionalConstProperties.json',
+            new GeneratorConfiguration(),
+            false,
+            $implicitNull,
+        );
+
+        $object = new $className(['requiredProperty' => $reqPropertyValue, 'optionalProperty' => $optPropertyValue]);
+
+        $this->assertSame($reqPropertyValue, $object->getRequiredProperty());
+        $this->assertSame($optPropertyValue, $object->getOptionalProperty());
+
+        // typing for required const
+        $this->assertSame('string', $this->getPropertyTypeAnnotation($object, 'requiredProperty'));
+
+        $this->assertSame('string', $this->getReturnTypeAnnotation($object, 'getRequiredProperty'));
+        $returnType = $this->getReturnType($object, 'getRequiredProperty');
+        $this->assertSame('string', $returnType->getName());
+        $this->assertFalse($returnType->allowsNull());
+
+        $this->assertSame('string', $this->getParameterTypeAnnotation($className, 'setRequiredProperty'),
+        );
+        $setAgeParamType = $this->getParameterType($className, 'setRequiredProperty');
+        $this->assertSame('string', $setAgeParamType->getName());
+        $this->assertFalse($returnType->allowsNull());
+
+        // typing for optional const
+        $this->assertSame('string|null', $this->getPropertyTypeAnnotation($object, 'optionalProperty'));
+
+        $this->assertSame('string|null', $this->getReturnTypeAnnotation($object, 'getOptionalProperty'));
+        $returnType = $this->getReturnType($object, 'getOptionalProperty');
+        $this->assertSame('string', $returnType->getName());
+        $this->assertTrue($returnType->allowsNull());
+
+        $this->assertSame(
+            $implicitNull ? 'string|null' : 'string',
+            $this->getParameterTypeAnnotation($className, 'setOptionalProperty'),
+        );
+        $setAgeParamType = $this->getParameterType($className, 'setOptionalProperty');
+        $this->assertSame('string', $setAgeParamType->getName());
+        $this->assertSame($implicitNull, $setAgeParamType->allowsNull());
+    }
+
+    public function requiredAndOptionalPropertiesDataProvider(): array
+    {
+        return $this->combineDataProvider(
+            $this->implicitNullDataProvider(),
+            [
+                ['red', 'green'],
+            ],
+        );
+    }
+
+    /**
+     * @throws FileSystemException
+     * @throws RenderException
+     * @throws SchemaException
+     */
+    public function testNotProvidedRequiredPropertyThrowsAnException(): void
+    {
+        $this->expectException(RequiredValueException::class);
+        $this->expectExceptionMessage('Missing required value for requiredProperty');
+
+        $className = $this->generateClassFromFile('RequiredAndOptionalConstProperties.json');
+
+        new $className([]);
+    }
+
+    /**
+     * @dataProvider invalidRequiredAndOptionalConstPropertiesDataProvider
+     *
+     * @throws FileSystemException
+     * @throws RenderException
+     * @throws SchemaException
+     */
+    public function testNotMatchingRequiredAndOptionalProvidedDataThrowsAnException(
+        bool $implicitNull,
+        string $reqPropertyValue,
+        ?string $optPropertyValue,
+        string $exceptionMessage
+    ): void
+    {
+        $className = $this->generateClassFromFile(
+            'RequiredAndOptionalConstProperties.json',
+            new GeneratorConfiguration(),
+            false,
+            $implicitNull,
+        );
+
+        $this->expectException(ErrorRegistryException::class);
+        $this->expectExceptionMessage($exceptionMessage);
+
+        new $className(['requiredProperty' => $reqPropertyValue, 'optionalProperty' => $optPropertyValue]);
+    }
+
+    public function invalidRequiredAndOptionalConstPropertiesDataProvider(): array
+    {
+        return $this->combineDataProvider(
+            $this->implicitNullDataProvider(),
+            [
+                ['blue', 'green', 'Invalid value for requiredProperty declined by const constraint'],
+                ['blue', null, 'Invalid value for requiredProperty declined by const constraint'],
+                ['red', 'blue', 'Invalid value for optionalProperty declined by const constraint'],
+                ['red', '0', 'Invalid value for optionalProperty declined by const constraint'],
+                ['red', '', 'Invalid value for optionalProperty declined by const constraint'],
+            ],
+        );
+    }
+
+    /**
+     * @dataProvider implicitNullDataProvider
+     */
+    public function testProvidedNullValueConstPropertyIsValid(bool $implicitNull): void
+    {
+        $className = $this->generateClassFromFile('NullValueConstProperty.json', implicitNull: $implicitNull);
+
+        $object = new $className(['nullProperty' => null]);
+
+        $this->assertNull($object->getNullProperty());
+    }
+
+    /**
+     * @dataProvider validConstAdditionalPropertiesDataProvider
+     */
+    public function testValidConstAdditionalProperties(array $value): void
+    {
+        $className = $this->generateClassFromFile('AdditionalPropertiesConst.json');
+
+        $object = new $className($value);
+
+        $this->assertSame($value, $object->getRawModelDataInput());
+    }
+
+    public function validConstAdditionalPropertiesDataProvider(): array
+    {
+        return [
+            'no properties'       => [[]],
+            'one property'        => [['property1' => 'red']],
+            'multiple properties' => [['property1' => 'red', 'property2' => 'red']],
+        ];
+    }
+
+    /**
+     * @dataProvider invalidConstAdditionalPropertiesDataProvider
+     */
+    public function testInvalidConstAdditionalPropertiesThrowsAnException(array $value): void
+    {
+        $this->expectException(InvalidAdditionalPropertiesException::class);
+        $this->expectExceptionMessageMatches('/Invalid value for additional property declined by const constraint/');
+
+        $className = $this->generateClassFromFile('AdditionalPropertiesConst.json');
+
+        new $className($value);
+    }
+
+    public function invalidConstAdditionalPropertiesDataProvider(): array
+    {
+        return [
+            'null'                           => [['property1' => null]],
+            'invalid value'                  => [['property1' => 'green']],
+            'mixed valid and invalid values' => [['property1' => 'red', 'property2' => 'green']],
+        ];
+    }
+
+    /**
+     * @dataProvider validConstPatternPropertiesDataProvider
+     */
+    public function testValidConstPatternProperties(array $value): void
+    {
+        $className = $this->generateClassFromFile('PatternPropertiesConst.json');
+
+        $object = new $className($value);
+
+        $this->assertSame($value, $object->getRawModelDataInput());
+    }
+
+    public function validConstPatternPropertiesDataProvider(): array
+    {
+        return [
+            'no properties'         => [[]],
+            'one property'          => [['property1' => 'red']],
+            'multiple properties'   => [['property1' => 'red', 'property2' => 'red']],
+            'not matching property' => [['different' => 'green']],
+        ];
+    }
+
+    /**
+     * @dataProvider invalidConstAdditionalPropertiesDataProvider
+     */
+    public function testInvalidConstPatternPropertiesThrowsAnException(array $value): void
+    {
+        $this->expectException(InvalidPatternPropertiesException::class);
+        $this->expectExceptionMessageMatches('/Invalid value for pattern property declined by const constraint/');
+
+        $className = $this->generateClassFromFile('PatternPropertiesConst.json');
+
+        new $className($value);
+    }
+
+
+    /**
+     * @dataProvider validConstArrayContainsDataProvider
+     */
+    public function testValidConstArrayContains(array $value): void
+    {
+        $className = $this->generateClassFromFile('ArrayContainsConst.json');
+
+        $object = new $className(['property' => $value]);
+
+        $this->assertSame($value, $object->getProperty());
+    }
+
+    public function validConstArrayContainsDataProvider(): array
+    {
+        return [
+            'one item'                    => [['red']],
+            'multiple items all matching' => [['red', 'red']],
+            'multiple items one matching' => [['green', 'red', 'yellow']],
+        ];
+    }
+
+    /**
+     * @dataProvider invalidConstArrayContainsDataProvider
+     */
+    public function testInvalidConstArrayContainsThrowsAnException(array $value): void
+    {
+        $this->expectException(ContainsException::class);
+        $this->expectExceptionMessage('No item in array property matches contains constraint');
+
+        $className = $this->generateClassFromFile('ArrayContainsConst.json');
+
+        new $className(['property' => $value]);
+    }
+
+    public function invalidConstArrayContainsDataProvider(): array
+    {
+        return [
+            'empty array'        => [[]],
+            'null'               => [[null]],
+            'value not in array' => [['green', 'yellow', 'blue']],
+        ];
+    }
 }
diff --git a/tests/Schema/ConstPropertyTest/AdditionalPropertiesConst.json b/tests/Schema/ConstPropertyTest/AdditionalPropertiesConst.json
new file mode 100644
index 00000000..4513ce30
--- /dev/null
+++ b/tests/Schema/ConstPropertyTest/AdditionalPropertiesConst.json
@@ -0,0 +1,6 @@
+{
+  "type": "object",
+  "additionalProperties": {
+    "const": "red"
+  }
+}
\ No newline at end of file
diff --git a/tests/Schema/ConstPropertyTest/ArrayContainsConst.json b/tests/Schema/ConstPropertyTest/ArrayContainsConst.json
new file mode 100644
index 00000000..fbca23b1
--- /dev/null
+++ b/tests/Schema/ConstPropertyTest/ArrayContainsConst.json
@@ -0,0 +1,11 @@
+{
+  "type": "object",
+  "properties": {
+    "property": {
+      "type": "array",
+      "contains": {
+        "const": "red"
+      }
+    }
+  }
+}
\ No newline at end of file
diff --git a/tests/Schema/ConstPropertyTest/ArrayItemConstProperty.json b/tests/Schema/ConstPropertyTest/ArrayItemConstProperty.json
new file mode 100644
index 00000000..7620d710
--- /dev/null
+++ b/tests/Schema/ConstPropertyTest/ArrayItemConstProperty.json
@@ -0,0 +1,11 @@
+{
+  "type": "object",
+  "properties": {
+    "property": {
+      "type": "array",
+      "items": {
+        "const": "red"
+      }
+    }
+  }
+}
\ No newline at end of file
diff --git a/tests/Schema/ConstPropertyTest/ArrayTupleConstProperty.json b/tests/Schema/ConstPropertyTest/ArrayTupleConstProperty.json
new file mode 100644
index 00000000..c111e74b
--- /dev/null
+++ b/tests/Schema/ConstPropertyTest/ArrayTupleConstProperty.json
@@ -0,0 +1,13 @@
+{
+  "type": "object",
+  "properties": {
+    "property": {
+      "type": "array",
+      "items": [
+        {
+          "const": "red"
+        }
+      ]
+    }
+  }
+}
\ No newline at end of file
diff --git a/tests/Schema/ConstPropertyTest/NullValueConstProperty.json b/tests/Schema/ConstPropertyTest/NullValueConstProperty.json
new file mode 100644
index 00000000..8ee4dc45
--- /dev/null
+++ b/tests/Schema/ConstPropertyTest/NullValueConstProperty.json
@@ -0,0 +1,11 @@
+{
+  "type": "object",
+  "properties": {
+    "nullProperty": {
+      "const": null
+    }
+  },
+  "required": [
+    "nullProperty"
+  ]
+}
\ No newline at end of file
diff --git a/tests/Schema/ConstPropertyTest/OneOfConstProperty.json b/tests/Schema/ConstPropertyTest/OneOfConstProperty.json
new file mode 100644
index 00000000..94d9539f
--- /dev/null
+++ b/tests/Schema/ConstPropertyTest/OneOfConstProperty.json
@@ -0,0 +1,15 @@
+{
+  "type": "object",
+  "properties": {
+    "property": {
+      "oneOf": [
+        {
+          "const": "red"
+        },
+        {
+          "const": 1
+        }
+      ]
+    }
+  }
+}
\ No newline at end of file
diff --git a/tests/Schema/ConstPropertyTest/PatternPropertiesConst.json b/tests/Schema/ConstPropertyTest/PatternPropertiesConst.json
new file mode 100644
index 00000000..885e885d
--- /dev/null
+++ b/tests/Schema/ConstPropertyTest/PatternPropertiesConst.json
@@ -0,0 +1,8 @@
+{
+  "type": "object",
+  "patternProperties": {
+    "property\\d+": {
+      "const": "red"
+    }
+  }
+}
\ No newline at end of file
diff --git a/tests/Schema/ConstPropertyTest/RequiredAndOptionalConstProperties.json b/tests/Schema/ConstPropertyTest/RequiredAndOptionalConstProperties.json
new file mode 100644
index 00000000..06987a0a
--- /dev/null
+++ b/tests/Schema/ConstPropertyTest/RequiredAndOptionalConstProperties.json
@@ -0,0 +1,14 @@
+{
+  "type": "object",
+  "properties": {
+    "requiredProperty": {
+      "const": "red"
+    },
+    "optionalProperty": {
+      "const": "green"
+    }
+  },
+  "required": [
+    "requiredProperty"
+  ]
+}
\ No newline at end of file
diff --git a/tests/manual/schema/person.json b/tests/manual/schema/person.json
index 0296a97a..1a946931 100644
--- a/tests/manual/schema/person.json
+++ b/tests/manual/schema/person.json
@@ -1,19 +1,15 @@
 {
-  "$id": "Person",
   "type": "object",
   "properties": {
-    "name": {
-      "type": "string",
-      "description": "The name of the person",
-      "example": "Lawrence"
-    },
-    "age": {
-      "type": "integer",
-      "description": "The age of the person",
-      "example": 42
+    "property": {
+      "oneOf": [
+        {
+          "const": "1"
+        },
+        {
+          "const": "2"
+        }
+      ]
     }
-  },
-  "required": [
-    "name"
-  ]
+  }
 }
\ No newline at end of file
diff --git a/tests/manual/test.php b/tests/manual/test.php
index 60456579..87d6c557 100644
--- a/tests/manual/test.php
+++ b/tests/manual/test.php
@@ -8,9 +8,15 @@
 
 $generator = new ModelGenerator((new GeneratorConfiguration())
     ->setNamespacePrefix('\\ManualSchema')
-    ->setImmutable(false),
+    ->setImmutable(false)
+    ->setCollectErrors(false)
+    ->setImplicitNull(false)
 );
 
 $generator
     ->generateModelDirectory(__DIR__ . '/result')
     ->generateModels(new RecursiveDirectoryProvider(__DIR__ . '/schema'), __DIR__ . '/result');
+
+$p = new \ManualSchema\Person(['property' => 1]);
+
+var_dump($p->getProperty());