diff --git a/openapi_core/schema/media_types/models.py b/openapi_core/schema/media_types/models.py
index 5cc278b..dce3737 100644
--- a/openapi_core/schema/media_types/models.py
+++ b/openapi_core/schema/media_types/models.py
@@ -32,17 +32,26 @@ class MediaType(object):
         deserializer = self.get_dererializer()
         return deserializer(value)
 
-    def unmarshal(self, value, custom_formatters=None):
+    def cast(self, value):
         if not self.schema:
             return value
 
         try:
-            deserialized = self.deserialize(value)
+            return self.deserialize(value)
         except ValueError as exc:
             raise InvalidMediaTypeValue(exc)
 
+    def unmarshal(self, value, custom_formatters=None, resolver=None):
+        if not self.schema:
+            return value
+
         try:
-            unmarshalled = self.schema.unmarshal(deserialized, custom_formatters=custom_formatters)
+            self.schema.validate(value, resolver=resolver)
+        except OpenAPISchemaError as exc:
+            raise InvalidMediaTypeValue(exc)
+
+        try:
+            unmarshalled = self.schema.unmarshal(value, custom_formatters=custom_formatters)
         except OpenAPISchemaError as exc:
             raise InvalidMediaTypeValue(exc)
 
diff --git a/openapi_core/schema/parameters/models.py b/openapi_core/schema/parameters/models.py
index f20b4f9..74ef1ae 100644
--- a/openapi_core/schema/parameters/models.py
+++ b/openapi_core/schema/parameters/models.py
@@ -72,7 +72,7 @@ class Parameter(object):
         deserializer = self.get_dererializer()
         return deserializer(value)
 
-    def get_value(self, request):
+    def get_raw_value(self, request):
         location = request.parameters[self.location.value]
 
         if self.name not in location:
@@ -89,7 +89,7 @@ class Parameter(object):
 
         return location[self.name]
 
-    def unmarshal(self, value, custom_formatters=None):
+    def cast(self, value):
         if self.deprecated:
             warnings.warn(
                 "{0} parameter is deprecated".format(self.name),
@@ -109,13 +109,22 @@ class Parameter(object):
             raise InvalidParameterValue(self.name, exc)
 
         try:
-            casted = self.schema.cast(deserialized)
+            return self.schema.cast(deserialized)
+        except OpenAPISchemaError as exc:
+            raise InvalidParameterValue(self.name, exc)
+
+    def unmarshal(self, value, custom_formatters=None, resolver=None):
+        if not self.schema:
+            return value
+
+        try:
+            self.schema.validate(value, resolver=resolver)
         except OpenAPISchemaError as exc:
             raise InvalidParameterValue(self.name, exc)
 
         try:
             unmarshalled = self.schema.unmarshal(
-                casted,
+                value,
                 custom_formatters=custom_formatters,
                 strict=True,
             )
diff --git a/openapi_core/schema/schemas/_format.py b/openapi_core/schema/schemas/_format.py
new file mode 100644
index 0000000..ec65771
--- /dev/null
+++ b/openapi_core/schema/schemas/_format.py
@@ -0,0 +1,9 @@
+from jsonschema._format import FormatChecker
+from six import binary_type
+
+oas30_format_checker = FormatChecker()
+
+
+@oas30_format_checker.checks('binary')
+def binary(value):
+    return isinstance(value, binary_type)
diff --git a/openapi_core/schema/schemas/_types.py b/openapi_core/schema/schemas/_types.py
new file mode 100644
index 0000000..12d1d26
--- /dev/null
+++ b/openapi_core/schema/schemas/_types.py
@@ -0,0 +1,21 @@
+from jsonschema._types import (
+    TypeChecker, is_any, is_array, is_bool, is_integer,
+    is_object, is_number,
+)
+from six import text_type, binary_type
+
+
+def is_string(checker, instance):
+    return isinstance(instance, (text_type, binary_type))
+
+
+oas30_type_checker = TypeChecker(
+    {
+        u"string": is_string,
+        u"number": is_number,
+        u"integer": is_integer,
+        u"boolean": is_bool,
+        u"array": is_array,
+        u"object": is_object,
+    },
+)
diff --git a/openapi_core/schema/schemas/_validators.py b/openapi_core/schema/schemas/_validators.py
new file mode 100644
index 0000000..19df6d3
--- /dev/null
+++ b/openapi_core/schema/schemas/_validators.py
@@ -0,0 +1,27 @@
+from jsonschema.exceptions import ValidationError
+
+
+def type(validator, data_type, instance, schema):
+    if instance is None:
+        return
+
+    if not validator.is_type(instance, data_type):
+        yield ValidationError("%r is not of type %s" % (instance, data_type))
+
+
+def items(validator, items, instance, schema):
+    if not validator.is_type(instance, "array"):
+        return
+
+    for index, item in enumerate(instance):
+        for error in validator.descend(item, items, path=index):
+            yield error
+
+
+def nullable(validator, is_nullable, instance, schema):
+    if instance is None and not is_nullable:
+        yield ValidationError("None for not nullable")
+
+
+def not_implemented(validator, value, instance, schema):
+    pass
diff --git a/openapi_core/schema/schemas/factories.py b/openapi_core/schema/schemas/factories.py
index 136fbd0..96229d3 100644
--- a/openapi_core/schema/schemas/factories.py
+++ b/openapi_core/schema/schemas/factories.py
@@ -50,11 +50,11 @@ class SchemaFactory(object):
 
         all_of = []
         if all_of_spec:
-            all_of = map(self.create, all_of_spec)
+            all_of = list(map(self.create, all_of_spec))
 
         one_of = []
         if one_of_spec:
-            one_of = map(self.create, one_of_spec)
+            one_of = list(map(self.create, one_of_spec))
 
         items = None
         if items_spec:
@@ -76,6 +76,7 @@ class SchemaFactory(object):
             exclusive_maximum=exclusive_maximum,
             exclusive_minimum=exclusive_minimum,
             min_properties=min_properties, max_properties=max_properties,
+            _source=schema_deref,
         )
 
     @property
diff --git a/openapi_core/schema/schemas/models.py b/openapi_core/schema/schemas/models.py
index 17fa44f..aa38e3d 100644
--- a/openapi_core/schema/schemas/models.py
+++ b/openapi_core/schema/schemas/models.py
@@ -9,8 +9,10 @@ import re
 import warnings
 
 from six import iteritems, integer_types, binary_type, text_type
+from jsonschema.exceptions import ValidationError
 
 from openapi_core.extensions.models.factories import ModelFactory
+from openapi_core.schema.schemas._format import oas30_format_checker
 from openapi_core.schema.schemas.enums import SchemaFormat, SchemaType
 from openapi_core.schema.schemas.exceptions import (
     InvalidSchemaValue, UndefinedSchemaProperty, MissingSchemaProperty,
@@ -23,7 +25,7 @@ from openapi_core.schema.schemas.util import (
     format_number,
 )
 from openapi_core.schema.schemas.validators import (
-    TypeValidator, AttributeValidator,
+    TypeValidator, AttributeValidator, OAS30Validator,
 )
 
 log = logging.getLogger(__name__)
@@ -85,7 +87,7 @@ class Schema(object):
             min_length=None, max_length=None, pattern=None, unique_items=False,
             minimum=None, maximum=None, multiple_of=None,
             exclusive_minimum=False, exclusive_maximum=False,
-            min_properties=None, max_properties=None):
+            min_properties=None, max_properties=None, _source=None):
         self.type = SchemaType(schema_type)
         self.model = model
         self.properties = properties and dict(properties) or {}
@@ -119,6 +121,8 @@ class Schema(object):
         self._all_required_properties_cache = None
         self._all_optional_properties_cache = None
 
+        self._source = _source
+
     def __getitem__(self, name):
         return self.properties[name]
 
@@ -214,6 +218,18 @@ class Schema(object):
 
         return defaultdict(lambda: lambda x: x, mapping)
 
+    def get_validator(self, resolver=None):
+        return OAS30Validator(
+            self._source, resolver=resolver, format_checker=oas30_format_checker)
+
+    def validate(self, value, resolver=None):
+        validator = self.get_validator(resolver=resolver)
+        try:
+            return validator.validate(value)
+        except ValidationError:
+            # TODO: pass validation errors
+            raise InvalidSchemaValue("Value not valid for schema", value, self.type)
+
     def unmarshal(self, value, custom_formatters=None, strict=True):
         """Unmarshal parameter from the value."""
         if self.deprecated:
@@ -241,10 +257,7 @@ class Schema(object):
                 "Value {value} is not of type {type}", value, self.type)
         except ValueError:
             raise InvalidSchemaValue(
-                "Failed to cast value {value} to type {type}", value, self.type)
-
-        if unmarshalled is None and not self.required:
-            return None
+                "Failed to unmarshal value {value} to type {type}", value, self.type)
 
         return unmarshalled
 
@@ -297,8 +310,7 @@ class Schema(object):
                     return unmarshal_callable(value)
                 except UnmarshallerStrictTypeError:
                     continue
-                # @todo: remove ValueError when validation separated
-                except (OpenAPISchemaError, TypeError, ValueError):
+                except (OpenAPISchemaError, TypeError):
                     continue
 
         raise NoValidSchema(value)
@@ -307,9 +319,6 @@ class Schema(object):
         if not isinstance(value, (list, tuple)):
             raise InvalidSchemaValue("Value {value} is not of type {type}", value, self.type)
 
-        if self.items is None:
-            raise UndefinedItemsSchema(self.type)
-
         f = functools.partial(
             self.items.unmarshal,
             custom_formatters=custom_formatters, strict=strict,
diff --git a/openapi_core/schema/schemas/validators.py b/openapi_core/schema/schemas/validators.py
index 2d9ec49..7d7b117 100644
--- a/openapi_core/schema/schemas/validators.py
+++ b/openapi_core/schema/schemas/validators.py
@@ -1,3 +1,10 @@
+from jsonschema import _legacy_validators, _format, _types, _utils, _validators
+from jsonschema.validators import create
+
+from openapi_core.schema.schemas import _types as oas_types
+from openapi_core.schema.schemas import _validators as oas_validators
+
+
 class TypeValidator(object):
 
     def __init__(self, *types, **options):
@@ -24,3 +31,50 @@ class AttributeValidator(object):
             return False
 
         return True
+
+
+OAS30Validator = create(
+    meta_schema=_utils.load_schema("draft4"),
+    validators={
+        u"multipleOf": _validators.multipleOf,
+        u"maximum": _legacy_validators.maximum_draft3_draft4,
+        u"exclusiveMaximum": _validators.exclusiveMaximum,
+        u"minimum": _legacy_validators.minimum_draft3_draft4,
+        u"exclusiveMinimum": _validators.exclusiveMinimum,
+        u"maxLength": _validators.maxLength,
+        u"minLength": _validators.minLength,
+        u"pattern": _validators.pattern,
+        u"maxItems": _validators.maxItems,
+        u"minItems": _validators.minItems,
+        u"uniqueItems": _validators.uniqueItems,
+        u"maxProperties": _validators.maxProperties,
+        u"minProperties": _validators.minProperties,
+        u"required": _validators.required,
+        u"enum": _validators.enum,
+        # adjusted to OAS
+        u"type": oas_validators.type,
+        u"allOf": _validators.allOf,
+        u"oneOf": _validators.oneOf,
+        u"anyOf": _validators.anyOf,
+        u"not": _validators.not_,
+        u"items": oas_validators.items,
+        u"properties": _validators.properties,
+        u"additionalProperties": _validators.additionalProperties,
+        # TODO: adjust description
+        u"format": _validators.format,
+        # TODO: adjust default
+        u"$ref": _validators.ref,
+        # fixed OAS fields
+        u"nullable": oas_validators.nullable,
+        u"discriminator": oas_validators.not_implemented,
+        u"readOnly": oas_validators.not_implemented,
+        u"writeOnly": oas_validators.not_implemented,
+        u"xml": oas_validators.not_implemented,
+        u"externalDocs": oas_validators.not_implemented,
+        u"example": oas_validators.not_implemented,
+        u"deprecated": oas_validators.not_implemented,
+    },
+    type_checker=oas_types.oas30_type_checker,
+    version="oas30",
+    id_of=lambda schema: schema.get(u"id", ""),
+)
diff --git a/openapi_core/schema/specs/factories.py b/openapi_core/schema/specs/factories.py
index 16f736d..0d31dd6 100644
--- a/openapi_core/schema/specs/factories.py
+++ b/openapi_core/schema/specs/factories.py
@@ -2,6 +2,7 @@
 """OpenAPI core specs factories module"""
 
 from openapi_spec_validator import openapi_v3_spec_validator
+from openapi_spec_validator.validators import Dereferencer
 
 from openapi_core.compat import lru_cache
 from openapi_core.schema.components.factories import ComponentsFactory
@@ -14,8 +15,8 @@ from openapi_core.schema.specs.models import Spec
 
 class SpecFactory(object):
 
-    def __init__(self, dereferencer, config=None):
-        self.dereferencer = dereferencer
+    def __init__(self, spec_resolver, config=None):
+        self.spec_resolver = spec_resolver
         self.config = config or {}
 
     def create(self, spec_dict, spec_url=''):
@@ -34,9 +35,16 @@ class SpecFactory(object):
         paths = self.paths_generator.generate(paths)
         components = self.components_factory.create(components_spec)
         spec = Spec(
-            info, list(paths), servers=list(servers), components=components)
+            info, list(paths), servers=list(servers), components=components,
+            _resolver=self.spec_resolver,
+        )
         return spec
 
+    @property
+    @lru_cache()
+    def dereferencer(self):
+        return Dereferencer(self.spec_resolver)
+
     @property
     @lru_cache()
     def schemas_registry(self):
diff --git a/openapi_core/schema/specs/models.py b/openapi_core/schema/specs/models.py
index 7e7c4e1..f4a115e 100644
--- a/openapi_core/schema/specs/models.py
+++ b/openapi_core/schema/specs/models.py
@@ -14,12 +14,14 @@ log = logging.getLogger(__name__)
 class Spec(object):
     """Represents an OpenAPI Specification for a service."""
 
-    def __init__(self, info, paths, servers=None, components=None):
+    def __init__(self, info, paths, servers=None, components=None, _resolver=None):
         self.info = info
         self.paths = paths and dict(paths)
         self.servers = servers or []
         self.components = components
 
+        self._resolver = _resolver
+
     def __getitem__(self, path_pattern):
         return self.get_path(path_pattern)
 
diff --git a/openapi_core/shortcuts.py b/openapi_core/shortcuts.py
index bcf4d31..02df1c1 100644
--- a/openapi_core/shortcuts.py
+++ b/openapi_core/shortcuts.py
@@ -1,6 +1,5 @@
 """OpenAPI core shortcuts module"""
 from jsonschema.validators import RefResolver
-from openapi_spec_validator.validators import Dereferencer
 from openapi_spec_validator import default_handlers
 
 from openapi_core.schema.media_types.exceptions import OpenAPIMediaTypeError
@@ -17,8 +16,7 @@ from openapi_core.validation.response.validators import ResponseValidator
 def create_spec(spec_dict, spec_url=''):
     spec_resolver = RefResolver(
         spec_url, spec_dict, handlers=default_handlers)
-    dereferencer = Dereferencer(spec_resolver)
-    spec_factory = SpecFactory(dereferencer)
+    spec_factory = SpecFactory(spec_resolver)
     return spec_factory.create(spec_dict, spec_url=spec_url)
 
 
diff --git a/openapi_core/validation/request/validators.py b/openapi_core/validation/request/validators.py
index 734b589..ba4851e 100644
--- a/openapi_core/validation/request/validators.py
+++ b/openapi_core/validation/request/validators.py
@@ -58,7 +58,7 @@ class RequestValidator(object):
                 continue
             seen.add((param_name, param.location.value))
             try:
-                raw_value = param.get_value(request)
+                raw_value = param.get_raw_value(request)
             except MissingParameter:
                 continue
             except OpenAPIMappingError as exc:
@@ -66,11 +66,20 @@ class RequestValidator(object):
                 continue
 
             try:
-                value = param.unmarshal(raw_value, self.custom_formatters)
+                casted = param.cast(raw_value)
+            except OpenAPIMappingError as exc:
+                errors.append(exc)
+                continue
+
+            try:
+                unmarshalled = param.unmarshal(
+                    casted, self.custom_formatters,
+                    resolver=self.spec._resolver,
+                )
             except OpenAPIMappingError as exc:
                 errors.append(exc)
             else:
-                parameters[param.location.value][param_name] = value
+                parameters[param.location.value][param_name] = unmarshalled
 
         return parameters, errors
 
@@ -92,8 +101,16 @@ class RequestValidator(object):
                 errors.append(exc)
             else:
                 try:
-                    body = media_type.unmarshal(raw_body, self.custom_formatters)
+                    casted = media_type.cast(raw_body)
                 except OpenAPIMappingError as exc:
                     errors.append(exc)
+                else:
+                    try:
+                        body = media_type.unmarshal(
+                            casted, self.custom_formatters,
+                            resolver=self.spec._resolver,
+                        )
+                    except OpenAPIMappingError as exc:
+                        errors.append(exc)
 
         return body, errors
diff --git a/openapi_core/validation/response/validators.py b/openapi_core/validation/response/validators.py
index 4f9696b..2ed923a 100644
--- a/openapi_core/validation/response/validators.py
+++ b/openapi_core/validation/response/validators.py
@@ -61,9 +61,17 @@ class ResponseValidator(object):
                 errors.append(exc)
             else:
                 try:
-                    data = media_type.unmarshal(raw_data, self.custom_formatters)
+                    casted = media_type.cast(raw_data)
                 except OpenAPIMappingError as exc:
                     errors.append(exc)
+                else:
+                    try:
+                        data = media_type.unmarshal(
+                            casted, self.custom_formatters,
+                            resolver=self.spec._resolver,
+                        )
+                    except OpenAPIMappingError as exc:
+                        errors.append(exc)
 
         return data, errors
 
diff --git a/tests/integration/data/v3.0/petstore.yaml b/tests/integration/data/v3.0/petstore.yaml
index efd817d..5f42339 100644
--- a/tests/integration/data/v3.0/petstore.yaml
+++ b/tests/integration/data/v3.0/petstore.yaml
@@ -317,7 +317,10 @@ components:
             suberror:
               $ref: "#/components/schemas/ExtendedError"
       additionalProperties:
-        type: string
+        oneOf:
+          - type: string
+          - type: integer
+            format: int32
   responses:
     ErrorResponse:
       description: unexpected error
diff --git a/tests/integration/test_petstore.py b/tests/integration/test_petstore.py
index 4c92c91..5e57c5e 100644
--- a/tests/integration/test_petstore.py
+++ b/tests/integration/test_petstore.py
@@ -19,9 +19,7 @@ from openapi_core.schema.paths.models import Path
 from openapi_core.schema.request_bodies.models import RequestBody
 from openapi_core.schema.responses.models import Response
 from openapi_core.schema.schemas.enums import SchemaType
-from openapi_core.schema.schemas.exceptions import (
-    InvalidSchemaProperty, InvalidSchemaValue,
-)
+from openapi_core.schema.schemas.exceptions import InvalidSchemaValue
 from openapi_core.schema.schemas.models import Schema
 from openapi_core.schema.servers.exceptions import InvalidServer
 from openapi_core.schema.servers.models import Server, ServerVariable
@@ -41,13 +39,17 @@ class TestPetstore(object):
         api_key_bytes_enc = b64encode(api_key_bytes)
         return text_type(api_key_bytes_enc, 'utf8')
 
+    @pytest.fixture
+    def spec_uri(self):
+        return "file://tests/integration/data/v3.0/petstore.yaml"
+
     @pytest.fixture
     def spec_dict(self, factory):
         return factory.spec_from_file("data/v3.0/petstore.yaml")
 
     @pytest.fixture
-    def spec(self, spec_dict):
-        return create_spec(spec_dict)
+    def spec(self, spec_dict, spec_uri):
+        return create_spec(spec_dict, spec_uri)
 
     @pytest.fixture
     def request_validator(self, spec):
@@ -267,6 +269,9 @@ class TestPetstore(object):
                 {
                     'id': 1,
                     'name': 'Cat',
+                    'ears': {
+                        'healthy': True,
+                    },
                 }
             ],
         }
@@ -322,16 +327,10 @@ class TestPetstore(object):
 
         assert response_result.errors == [
             InvalidMediaTypeValue(
-                original_exception=InvalidSchemaProperty(
-                    property_name='data',
-                    original_exception=InvalidSchemaProperty(
-                        property_name='name',
-                        original_exception=InvalidSchemaValue(
-                            msg="Value {value} is not of type {type}",
-                            type=SchemaType.STRING,
-                            value={'first_name': 'Cat'},
-                        ),
-                    ),
+                original_exception=InvalidSchemaValue(
+                    msg='Value not valid for schema',
+                    type=SchemaType.OBJECT,
+                    value=data_json,
                 ),
             ),
         ]
@@ -932,6 +931,9 @@ class TestPetstore(object):
             'data': {
                 'id': data_id,
                 'name': data_name,
+                'ears': {
+                    'healthy': True,
+                },
             },
         }
         data = json.dumps(data_json)
@@ -1239,7 +1241,6 @@ class TestPetstore(object):
         assert response_result.data.rootCause == rootCause
         assert response_result.data.additionalinfo == additionalinfo
 
-    @pytest.mark.xfail(reason='OneOf for string not supported atm')
     def test_post_tags_created_invalid_type(
             self, spec, response_validator):
         host_url = 'http://petstore.swagger.io/v1'
diff --git a/tests/integration/test_validators.py b/tests/integration/test_validators.py
index 2f26a7b..2d3af8f 100644
--- a/tests/integration/test_validators.py
+++ b/tests/integration/test_validators.py
@@ -421,6 +421,17 @@ class TestResponseValidator(object):
         assert result.data is None
         assert result.headers == {}
 
+    def test_invalid_media_type(self, validator):
+        request = MockRequest(self.host_url, 'get', '/v1/pets')
+        response = MockResponse("abcde")
+
+        result = validator.validate(request, response)
+
+        assert len(result.errors) == 1
+        assert type(result.errors[0]) == InvalidMediaTypeValue
+        assert result.data is None
+        assert result.headers == {}
+
     def test_invalid_media_type_value(self, validator):
         request = MockRequest(self.host_url, 'get', '/v1/pets')
         response = MockResponse("{}")
@@ -458,7 +469,10 @@ class TestResponseValidator(object):
             'data': [
                 {
                     'id': 1,
-                    'name': 'Sparky'
+                    'name': 'Sparky',
+                    'ears': {
+                        'healthy': True,
+                    },
                 },
             ],
         }
diff --git a/tests/unit/schema/test_media_types.py b/tests/unit/schema/test_media_types.py
new file mode 100644
index 0000000..2d266ac
--- /dev/null
+++ b/tests/unit/schema/test_media_types.py
@@ -0,0 +1,53 @@
+import pytest
+
+from openapi_core.schema.media_types.exceptions import InvalidMediaTypeValue
+from openapi_core.schema.media_types.models import MediaType
+from openapi_core.schema.schemas.models import Schema
+
+
+class TestMediaTypeCast(object):
+
+    def test_empty(self):
+        media_type = MediaType('application/json')
+        value = ''
+
+        result = media_type.cast(value)
+
+        assert result == value
+
+
+class TestParameterUnmarshal(object):
+
+    def test_empty(self):
+        media_type = MediaType('application/json')
+        value = ''
+
+        result = media_type.unmarshal(value)
+
+        assert result == value
+
+    def test_schema_type_invalid(self):
+        schema = Schema('integer', _source={'type': 'integer'})
+        media_type = MediaType('application/json', schema=schema)
+        value = 'test'
+
+        with pytest.raises(InvalidMediaTypeValue):
+            media_type.unmarshal(value)
+
+    def test_schema_custom_format_invalid(self):
+        def custom_formatter(value):
+            raise ValueError
+        schema = Schema(
+            'string',
+            schema_format='custom',
+            _source={'type': 'string', 'format': 'custom'},
+        )
+        custom_formatters = {
+            'custom': custom_formatter,
+        }
+        media_type = MediaType('application/json', schema=schema)
+        value = 'test'
+
+        with pytest.raises(InvalidMediaTypeValue):
+            media_type.unmarshal(
+                value, custom_formatters=custom_formatters)
diff --git a/tests/unit/schema/test_parameters.py b/tests/unit/schema/test_parameters.py
index 952e956..2755dcb 100644
--- a/tests/unit/schema/test_parameters.py
+++ b/tests/unit/schema/test_parameters.py
@@ -1,8 +1,11 @@
 import pytest
 
-from openapi_core.schema.parameters.exceptions import EmptyParameterValue
+from openapi_core.schema.parameters.exceptions import (
+    EmptyParameterValue, InvalidParameterValue,
+)
 from openapi_core.schema.parameters.enums import ParameterStyle
 from openapi_core.schema.parameters.models import Parameter
+from openapi_core.schema.schemas.models import Schema
 
 
 class TestParameterInit(object):
@@ -36,17 +39,35 @@ class TestParameterInit(object):
         assert param.explode is True
 
 
-class TestParameterUnmarshal(object):
+class TestParameterCast(object):
 
     def test_deprecated(self):
         param = Parameter('param', 'query', deprecated=True)
         value = 'test'
 
         with pytest.warns(DeprecationWarning):
-            result = param.unmarshal(value)
+            result = param.cast(value)
 
         assert result == value
 
+    def test_query_empty(self):
+        param = Parameter('param', 'query')
+        value = ''
+
+        with pytest.raises(EmptyParameterValue):
+            param.cast(value)
+
+    def test_query_valid(self):
+        param = Parameter('param', 'query')
+        value = 'test'
+
+        result = param.cast(value)
+
+        assert result == value
+
+
+class TestParameterUnmarshal(object):
+
     def test_query_valid(self):
         param = Parameter('param', 'query')
         value = 'test'
@@ -55,13 +76,6 @@ class TestParameterUnmarshal(object):
 
         assert result == value
 
-    def test_query_empty(self):
-        param = Parameter('param', 'query')
-        value = ''
-
-        with pytest.raises(EmptyParameterValue):
-            param.unmarshal(value)
-
     def test_query_allow_empty_value(self):
         param = Parameter('param', 'query', allow_empty_value=True)
         value = ''
@@ -69,3 +83,28 @@ class TestParameterUnmarshal(object):
         result = param.unmarshal(value)
 
         assert result == value
+
+    def test_query_schema_type_invalid(self):
+        schema = Schema('integer', _source={'type': 'integer'})
+        param = Parameter('param', 'query', schema=schema)
+        value = 'test'
+
+        with pytest.raises(InvalidParameterValue):
+            param.unmarshal(value)
+
+    def test_query_schema_custom_format_invalid(self):
+        def custom_formatter(value):
+            raise ValueError
+        schema = Schema(
+            'string',
+            schema_format='custom',
+            _source={'type': 'string', 'format': 'custom'},
+        )
+        custom_formatters = {
+            'custom': custom_formatter,
+        }
+        param = Parameter('param', 'query', schema=schema)
+        value = 'test'
+
+        with pytest.raises(InvalidParameterValue):
+            param.unmarshal(value, custom_formatters=custom_formatters)
diff --git a/tests/unit/schema/test_schemas.py b/tests/unit/schema/test_schemas.py
index 0e7a2fe..4436ff8 100644
--- a/tests/unit/schema/test_schemas.py
+++ b/tests/unit/schema/test_schemas.py
@@ -42,6 +42,17 @@ class TestSchemaUnmarshal(object):
 
         assert result == value
 
+    @pytest.mark.parametrize('schema_type', [
+        'boolean', 'array', 'integer', 'number',
+    ])
+    def test_non_string_empty_value(self, schema_type):
+        schema = Schema(schema_type)
+        value = ''
+
+        result = schema.unmarshal(value)
+
+        assert result is None
+
     def test_string_valid(self):
         schema = Schema('string')
         value = 'test'
@@ -121,19 +132,28 @@ class TestSchemaUnmarshal(object):
 
         assert result == datetime.datetime(2018, 1, 2, 0, 0)
 
-    @pytest.mark.xfail(reason="No custom formats support atm")
     def test_string_format_custom(self):
+        def custom_formatter(value):
+            return 'x-custom'
         custom_format = 'custom'
         schema = Schema('string', schema_format=custom_format)
         value = 'x'
 
-        with mock.patch.dict(
-            Schema.STRING_FORMAT_CAST_CALLABLE_GETTER,
-            {custom_format: lambda x: x + '-custom'},
-        ):
-            result = schema.unmarshal(value)
+        result = schema.unmarshal(
+            value, custom_formatters={custom_format: custom_formatter})
 
-        assert result == 'x-custom'
+        assert result == custom_formatter(value)
+
+    def test_string_format_custom_value_error(self):
+        def custom_formatter(value):
+            raise ValueError
+        custom_format = 'custom'
+        schema = Schema('string', schema_format=custom_format)
+        value = 'x'
+
+        with pytest.raises(InvalidSchemaValue):
+            schema.unmarshal(
+                value, custom_formatters={custom_format: custom_formatter})
 
     def test_string_format_unknown(self):
         unknown_format = 'unknown'
@@ -143,7 +163,6 @@ class TestSchemaUnmarshal(object):
         with pytest.raises(OpenAPISchemaError):
             schema.unmarshal(value)
 
-    @pytest.mark.xfail(reason="No custom formats support atm")
     def test_string_format_invalid_value(self):
         custom_format = 'custom'
         schema = Schema('string', schema_format=custom_format)
@@ -351,6 +370,14 @@ class TestSchemaObjValidate(object):
 
         assert result is None
 
+    def test_string_format_custom_missing(self):
+        custom_format = 'custom'
+        schema = Schema('string', schema_format=custom_format)
+        value = 'x'
+
+        with pytest.raises(OpenAPISchemaError):
+            schema.obj_validate(value)
+
     @pytest.mark.parametrize('value', [False, True])
     def test_boolean(self, value):
         schema = Schema('boolean')