Tests fixed

src/Squidex.Domain.Apps.Core.Model/Apps/Json/AppClientsConverter.cs

@@ -6,21 +6,19 @@
 //  All rights reserved.
 // ==========================================================================
 
-using System;
 using System.Collections.Generic;
 using Newtonsoft.Json;
+using Squidex.Infrastructure.Json;
 
 namespace Squidex.Domain.Apps.Core.Apps.Json
 {
-    public sealed class AppClientsConverter : JsonConverter
+    public sealed class AppClientsConverter : JsonClassConverter<AppClients>
     {
-        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
+        protected override void WriteValue(JsonWriter writer, AppClients value, JsonSerializer serializer)
         {
-            var clients = (AppClients)value;
+            var json = new Dictionary<string, JsonAppClient>(value.Count);
 
-            var json = new Dictionary<string, JsonAppClient>(clients.Count);
-
-            foreach (var client in clients)
+            foreach (var client in value)
             {
                 json.Add(client.Key, new JsonAppClient(client.Value));
             }
@@ -28,7 +26,7 @@ namespace Squidex.Domain.Apps.Core.Apps.Json
             serializer.Serialize(writer, json);
         }
 
-        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
+        protected override AppClients ReadValue(JsonReader reader, JsonSerializer serializer)
         {
             var json = serializer.Deserialize<Dictionary<string, JsonAppClient>>(reader);
 
@@ -41,10 +39,5 @@ namespace Squidex.Domain.Apps.Core.Apps.Json
 
             return clients;
         }
-
-        public override bool CanConvert(Type objectType)
-        {
-            return objectType == typeof(AppClients);
-        }
     }
 }

src/Squidex.Domain.Apps.Core.Model/Apps/Json/AppContributorsConverter.cs

@@ -6,21 +6,19 @@
 //  All rights reserved.
 // ==========================================================================
 
-using System;
 using System.Collections.Generic;
 using Newtonsoft.Json;
+using Squidex.Infrastructure.Json;
 
 namespace Squidex.Domain.Apps.Core.Apps.Json
 {
-    public sealed class AppContributorsConverter : JsonConverter
+    public sealed class AppContributorsConverter : JsonClassConverter<AppContributors>
     {
-        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
+        protected override void WriteValue(JsonWriter writer, AppContributors value, JsonSerializer serializer)
         {
-            var contributors = (AppContributors)value;
+            var json = new Dictionary<string, AppContributorPermission>(value.Count);
 
-            var json = new Dictionary<string, AppContributorPermission>(contributors.Count);
-
-            foreach (var contributor in contributors)
+            foreach (var contributor in value)
             {
                 json.Add(contributor.Key, contributor.Value);
             }
@@ -28,7 +26,7 @@ namespace Squidex.Domain.Apps.Core.Apps.Json
             serializer.Serialize(writer, json);
         }
 
-        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
+        protected override AppContributors ReadValue(JsonReader reader, JsonSerializer serializer)
         {
             var json = serializer.Deserialize<Dictionary<string, AppContributorPermission>>(reader);
 
@@ -41,10 +39,5 @@ namespace Squidex.Domain.Apps.Core.Apps.Json
 
             return contributors;
         }
-
-        public override bool CanConvert(Type objectType)
-        {
-            return objectType == typeof(AppContributors);
-        }
     }
 }

src/Squidex.Domain.Apps.Core.Model/Apps/Json/LanguagesConfigConverter.cs

@@ -6,21 +6,19 @@
 //  All rights reserved.
 // ==========================================================================
 
-using System;
 using System.Collections.Generic;
 using Newtonsoft.Json;
+using Squidex.Infrastructure.Json;
 
 namespace Squidex.Domain.Apps.Core.Apps.Json
 {
-    public sealed class LanguagesConfigConverter : JsonConverter
+    public sealed class LanguagesConfigConverter : JsonClassConverter<LanguagesConfig>
     {
-        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
+        protected override void WriteValue(JsonWriter writer, LanguagesConfig value, JsonSerializer serializer)
         {
-            var languagesConfig = (LanguagesConfig)value;
+            var json = new Dictionary<string, JsonLanguageConfig>(value.Count);
 
-            var json = new Dictionary<string, JsonLanguageConfig>(languagesConfig.Count);
-
-            foreach (var config in languagesConfig.Configs)
+            foreach (LanguageConfig config in value)
             {
                 json.Add(config.Language, new JsonLanguageConfig(config));
             }
@@ -28,7 +26,7 @@ namespace Squidex.Domain.Apps.Core.Apps.Json
             serializer.Serialize(writer, json);
         }
 
-        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
+        protected override LanguagesConfig ReadValue(JsonReader reader, JsonSerializer serializer)
         {
             var json = serializer.Deserialize<Dictionary<string, JsonLanguageConfig>>(reader);
 
@@ -43,10 +41,5 @@ namespace Squidex.Domain.Apps.Core.Apps.Json
 
             return LanguagesConfig.Build(languagesConfig);
         }
-
-        public override bool CanConvert(Type objectType)
-        {
-            return objectType == typeof(LanguagesConfig);
-        }
     }
 }

src/Squidex.Domain.Apps.Core.Model/Apps/LanguagesConfig.cs

@@ -41,11 +41,6 @@ namespace Squidex.Domain.Apps.Core.Apps
             return state.Languages.Values.GetEnumerator();
         }
 
-        public IEnumerable<LanguageConfig> Configs
-        {
-            get { return state.Languages.Values; }
-        }
-
         public int Count
         {
             get { return state.Languages.Count; }

src/Squidex.Domain.Apps.Core.Model/Schemas/Json/SchemaConverter.cs

@@ -6,13 +6,13 @@
 //  All rights reserved.
 // ==========================================================================
 
-using System;
 using Newtonsoft.Json;
 using Squidex.Infrastructure;
+using Squidex.Infrastructure.Json;
 
 namespace Squidex.Domain.Apps.Core.Schemas.Json
 {
-    public sealed class SchemaConverter : JsonConverter
+    public sealed class SchemaConverter : JsonClassConverter<Schema>
     {
         private readonly FieldRegistry fieldRegistry;
 
@@ -23,19 +23,14 @@ namespace Squidex.Domain.Apps.Core.Schemas.Json
             this.fieldRegistry = fieldRegistry;
         }
 
-        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
+        protected override void WriteValue(JsonWriter writer, Schema value, JsonSerializer serializer)
         {
-            serializer.Serialize(writer, new JsonSchemaModel((Schema)value));
+            serializer.Serialize(writer, new JsonSchemaModel(value));
         }
 
-        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
+        protected override Schema ReadValue(JsonReader reader, JsonSerializer serializer)
         {
             return serializer.Deserialize<JsonSchemaModel>(reader).ToSchema(fieldRegistry);
         }
-
-        public override bool CanConvert(Type objectType)
-        {
-            return objectType == typeof(Schema);
-        }
     }
 }

src/Squidex.Infrastructure/Json/ClaimsPrincipalConverter.cs

@@ -0,0 +1,62 @@
+// ==========================================================================
+//  ClaimsPrincipalConverter.cs
+//  Squidex Headless CMS
+// ==========================================================================
+//  Copyright (c) Squidex Group
+//  All rights reserved.
+// ==========================================================================
+
+using System.Linq;
+using System.Security.Claims;
+using Newtonsoft.Json;
+
+namespace Squidex.Infrastructure.Json
+{
+    public sealed class ClaimsPrincipalConverter : JsonClassConverter<ClaimsPrincipal>
+    {
+        private sealed class JsonIdentity
+        {
+            [JsonProperty]
+            public string AuthenticationType { get; set; }
+
+            [JsonProperty]
+            public JsonClaim[] Claims { get; set; }
+        }
+
+        private sealed class JsonClaim
+        {
+            [JsonProperty]
+            public string Type { get; set; }
+
+            [JsonProperty]
+            public string Value { get; set; }
+        }
+
+        protected override void WriteValue(JsonWriter writer, ClaimsPrincipal value, JsonSerializer serializer)
+        {
+            var jsonIdentities =
+                value.Identities.Select(identity =>
+                    new JsonIdentity
+                    {
+                        Claims = identity.Claims.Select(c =>
+                        {
+                            return new JsonClaim { Type = c.Type, Value = c.Value };
+                        }).ToArray(),
+                        AuthenticationType = identity.AuthenticationType
+                    }).ToArray();
+
+            serializer.Serialize(writer, jsonIdentities);
+        }
+
+        protected override ClaimsPrincipal ReadValue(JsonReader reader, JsonSerializer serializer)
+        {
+            var jsonIdentities = serializer.Deserialize<JsonIdentity[]>(reader);
+
+            return new ClaimsPrincipal(
+                jsonIdentities.Select(identity =>
+                    new ClaimsIdentity(
+                        identity.Claims.Select(c => new Claim(c.Type, c.Value)),
+                        identity.AuthenticationType)));
+        }
+    }
+}

src/Squidex.Infrastructure/Json/JsonClassConverter.cs

@@ -0,0 +1,46 @@
+// ==========================================================================
+//  JsonClassConverter.cs
+//  Squidex Headless CMS
+// ==========================================================================
+//  Copyright (c) Squidex Group
+//  All rights reserved.
+// ==========================================================================
+
+using System;
+using Newtonsoft.Json;
+
+namespace Squidex.Infrastructure.Json
+{
+    public abstract class JsonClassConverter<T> : JsonConverter where T : class
+    {
+        public sealed override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
+        {
+            if (reader.TokenType == JsonToken.Null)
+            {
+                return null;
+            }
+
+            return ReadValue(reader, serializer);
+        }
+
+        public sealed override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
+        {
+            if (value == null)
+            {
+                writer.WriteNull();
+                return;
+            }
+
+            WriteValue(writer, (T)value, serializer);
+        }
+
+        public override bool CanConvert(Type objectType)
+        {
+            return objectType == typeof(T);
+        }
+
+        protected abstract void WriteValue(JsonWriter writer, T value, JsonSerializer serializer);
+
+        protected abstract T ReadValue(JsonReader reader, JsonSerializer serializer);
+    }
+}

src/Squidex.Infrastructure/Json/LanguageConverter.cs

@@ -6,26 +6,25 @@
 //  All rights reserved.
 // ==========================================================================
 
-using System;
 using Newtonsoft.Json;
 
 namespace Squidex.Infrastructure.Json
 {
-    public sealed class LanguageConverter : JsonConverter
+    public sealed class LanguageConverter : JsonClassConverter<Language>
     {
-        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
+        protected override void WriteValue(JsonWriter writer, Language value, JsonSerializer serializer)
         {
-            writer.WriteValue(((Language)value).Iso2Code);
+            writer.WriteValue(value.Iso2Code);
         }
 
-        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
+        protected override Language ReadValue(JsonReader reader, JsonSerializer serializer)
         {
-            return reader.TokenType == JsonToken.Null ? null : Language.GetLanguage((string)reader.Value);
+            if (reader.TokenType != JsonToken.String)
+            {
+                throw new JsonException($"Expected String, but got {reader.TokenType}.");
             }
 
-        public override bool CanConvert(Type objectType)
-        {
-            return objectType == typeof(Language);
+            return Language.GetLanguage(reader.Value.ToString());
         }
     }
 }

src/Squidex.Infrastructure/Json/NamedGuidIdConverter.cs

@@ -12,23 +12,21 @@ using Newtonsoft.Json;
 
 namespace Squidex.Infrastructure.Json
 {
-    public sealed class NamedGuidIdConverter : JsonConverter
+    public sealed class NamedGuidIdConverter : JsonClassConverter<NamedId<Guid>>
     {
-        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
+        protected override void WriteValue(JsonWriter writer, NamedId<Guid> value, JsonSerializer serializer)
         {
-            var namedId = (NamedId<Guid>)value;
-
-            writer.WriteValue($"{namedId.Id},{namedId.Name}");
+            writer.WriteValue($"{value.Id},{value.Name}");
         }
 
-        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
+        protected override NamedId<Guid> ReadValue(JsonReader reader, JsonSerializer serializer)
         {
-            if (reader.TokenType == JsonToken.Null)
+            if (reader.TokenType != JsonToken.String)
             {
-                return null;
+                throw new JsonException($"Expected String, but got {reader.TokenType}.");
             }
 
-            var parts = ((string)reader.Value).Split(new[] { ',' }, StringSplitOptions.RemoveEmptyEntries);
+            var parts = reader.Value.ToString().Split(new[] { ',' }, StringSplitOptions.RemoveEmptyEntries);
 
             if (parts.Length < 2)
             {
@@ -42,10 +40,5 @@ namespace Squidex.Infrastructure.Json
 
             return new NamedId<Guid>(id, string.Join(",", parts.Skip(1)));
         }
-
-        public override bool CanConvert(Type objectType)
-        {
-            return objectType == typeof(NamedId<Guid>);
-        }
     }
 }

src/Squidex.Infrastructure/Json/NamedLongIdConverter.cs

@@ -12,23 +12,21 @@ using Newtonsoft.Json;
 
 namespace Squidex.Infrastructure.Json
 {
-    public sealed class NamedLongIdConverter : JsonConverter
+    public sealed class NamedLongIdConverter : JsonClassConverter<NamedId<long>>
     {
-        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
+        protected override void WriteValue(JsonWriter writer, NamedId<long> value, JsonSerializer serializer)
         {
-            var namedId = (NamedId<long>)value;
-
-            writer.WriteValue($"{namedId.Id},{namedId.Name}");
+            writer.WriteValue($"{value.Id},{value.Name}");
         }
 
-        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
+        protected override NamedId<long> ReadValue(JsonReader reader, JsonSerializer serializer)
         {
-            if (reader.TokenType == JsonToken.Null)
+            if (reader.TokenType != JsonToken.String)
             {
-                return null;
+                throw new JsonException($"Expected String, but got {reader.TokenType}.");
             }
 
-            var parts = ((string)reader.Value).Split(new[] { ',' }, StringSplitOptions.RemoveEmptyEntries);
+            var parts = reader.Value.ToString().Split(new[] { ',' }, StringSplitOptions.RemoveEmptyEntries);
 
             if (parts.Length < 2)
             {
@@ -42,10 +40,5 @@ namespace Squidex.Infrastructure.Json
 
             return new NamedId<long>(id, string.Join(",", parts.Skip(1)));
         }
-
-        public override bool CanConvert(Type objectType)
-        {
-            return objectType == typeof(NamedId<long>);
-        }
     }
 }

src/Squidex.Infrastructure/Json/NamedStringIdConverter.cs

@@ -12,23 +12,21 @@ using Newtonsoft.Json;
 
 namespace Squidex.Infrastructure.Json
 {
-    public sealed class NamedStringIdConverter : JsonConverter
+    public sealed class NamedStringIdConverter : JsonClassConverter<NamedId<string>>
     {
-        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
+        protected override void WriteValue(JsonWriter writer, NamedId<string> value, JsonSerializer serializer)
         {
-            var namedId = (NamedId<string>)value;
-
-            writer.WriteValue($"{namedId.Id},{namedId.Name}");
+            writer.WriteValue($"{value.Id},{value.Name}");
         }
 
-        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
+        protected override NamedId<string> ReadValue(JsonReader reader, JsonSerializer serializer)
         {
-            if (reader.TokenType == JsonToken.Null)
+            if (reader.TokenType != JsonToken.String)
             {
-                return null;
+                throw new JsonException($"Expected String, but got {reader.TokenType}.");
             }
 
-            var parts = ((string)reader.Value).Split(new[] { ',' }, StringSplitOptions.RemoveEmptyEntries);
+            var parts = reader.Value.ToString().Split(new[] { ',' }, StringSplitOptions.RemoveEmptyEntries);
 
             if (parts.Length < 2)
             {
@@ -37,10 +35,5 @@ namespace Squidex.Infrastructure.Json
 
             return new NamedId<string>(parts[0], string.Join(",", parts.Skip(1)));
         }
-
-        public override bool CanConvert(Type objectType)
-        {
-            return objectType == typeof(NamedId<string>);
-        }
     }
 }

src/Squidex.Infrastructure/Json/PropertiesBagConverter.cs

@@ -13,15 +13,36 @@ using NodaTime.Extensions;
 
 namespace Squidex.Infrastructure.Json
 {
-    public sealed class PropertiesBagConverter : JsonConverter
+    public sealed class PropertiesBagConverter : JsonClassConverter<PropertiesBag>
     {
-        public override bool CanConvert(Type objectType)
+        protected override void WriteValue(JsonWriter writer, PropertiesBag value, JsonSerializer serializer)
         {
-            return typeof(PropertiesBag).IsAssignableFrom(objectType);
+            writer.WriteStartObject();
+
+            foreach (var kvp in value.Properties)
+            {
+                writer.WritePropertyName(kvp.Key);
+
+                if (kvp.Value.RawValue is Instant)
+                {
+                    writer.WriteValue(kvp.Value.ToString());
+                }
+                else
+                {
+                    writer.WriteValue(kvp.Value.RawValue);
+                }
             }
 
-        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
+            writer.WriteEndObject();
+        }
+
+        protected override PropertiesBag ReadValue(JsonReader reader, JsonSerializer serializer)
         {
+            if (reader.TokenType != JsonToken.StartObject)
+            {
+                throw new JsonException($"Expected Object, but got {reader.TokenType}.");
+            }
+
             var properties = new PropertiesBag();
 
             while (reader.Read())
@@ -50,27 +71,9 @@ namespace Squidex.Infrastructure.Json
             return properties;
         }
 
-        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
-        {
-            var properties = (PropertiesBag)value;
-
-            writer.WriteStartObject();
-
-            foreach (var kvp in properties.Properties)
-            {
-                writer.WritePropertyName(kvp.Key);
-
-                if (kvp.Value.RawValue is Instant)
-                {
-                    writer.WriteValue(kvp.Value.ToString());
-                }
-                else
+        public override bool CanConvert(Type objectType)
         {
-                    writer.WriteValue(kvp.Value.RawValue);
-                }
-            }
-
-            writer.WriteEndObject();
+            return typeof(PropertiesBag).IsAssignableFrom(objectType);
         }
     }
 }

src/Squidex.Infrastructure/Json/RefTokenConverter.cs

@@ -6,26 +6,25 @@
 //  All rights reserved.
 // ==========================================================================
 
-using System;
 using Newtonsoft.Json;
 
 namespace Squidex.Infrastructure.Json
 {
-    public sealed class RefTokenConverter : JsonConverter
+    public sealed class RefTokenConverter : JsonClassConverter<RefToken>
     {
-        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
+        protected override void WriteValue(JsonWriter writer, RefToken value, JsonSerializer serializer)
         {
             writer.WriteValue(value.ToString());
         }
 
-        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
+        protected override RefToken ReadValue(JsonReader reader, JsonSerializer serializer)
         {
-            return reader.TokenType == JsonToken.Null ? null : RefToken.Parse((string)reader.Value);
+            if (reader.TokenType != JsonToken.String)
+            {
+                throw new JsonException($"Expected String, but got {reader.TokenType}.");
             }
 
-        public override bool CanConvert(Type objectType)
-        {
-            return objectType == typeof(RefToken);
+            return RefToken.Parse(reader.Value.ToString());
         }
     }
 }

src/Squidex/Config/Domain/Serializers.cs

@@ -36,6 +36,7 @@ namespace Squidex.Config.Domain
             settings.ContractResolver = new ConverterContractResolver(
                 new AppClientsConverter(),
                 new AppContributorsConverter(),
+                new ClaimsPrincipalConverter(),
                 new InstantConverter(),
                 new LanguageConverter(),
                 new LanguagesConfigConverter(),

tests/Squidex.Domain.Apps.Core.Tests/Model/Apps/LanguagesConfigTests.cs

@@ -172,14 +172,6 @@ namespace Squidex.Domain.Apps.Core.Model.Apps
             config.Remove(Language.EN);
         }
 
-        [Fact]
-        public void Should_throw_exception_if_language_to_remove_is_master_language()
-        {
-            var config = LanguagesConfig.Build(Language.DE);
-
-            Assert.Throws<InvalidOperationException>(() => config.Remove(Language.DE));
-        }
-
         [Fact]
         public void Should_update_language()
         {

tests/Squidex.Infrastructure.Tests/Json/ClaimsPrincipalConverterTests.cs

@@ -0,0 +1,54 @@
+// ==========================================================================
+//  ClaimsPrincipalConverterTests.cs
+//  Squidex Headless CMS
+// ==========================================================================
+//  Copyright (c) Squidex Group
+//  All rights reserved.
+// ==========================================================================
+
+using System.Linq;
+using System.Security.Claims;
+using Squidex.Infrastructure.TestHelpers;
+using Xunit;
+
+namespace Squidex.Infrastructure.Json
+{
+    public class ClaimsPrincipalConverterTests
+    {
+        [Fact]
+        public void Should_serialize_and_deserialize()
+        {
+            var value = new ClaimsPrincipal(
+                new[]
+                {
+                    new ClaimsIdentity(
+                        new[]
+                        {
+                            new Claim("email", "me@email.de"),
+                            new Claim("username", "me@email.de"),
+                        },
+                        "Cookie"),
+                    new ClaimsIdentity(
+                        new[]
+                        {
+                            new Claim("user_id", "12345"),
+                            new Claim("login", "me"),
+                        },
+                        "Google")
+                });
+
+            var result = value.SerializeAndDeserializeAndReturn(new ClaimsPrincipalConverter());
+
+            Assert.Equal(value.Identities.ElementAt(0).AuthenticationType, result.Identities.ElementAt(0).AuthenticationType);
+            Assert.Equal(value.Identities.ElementAt(1).AuthenticationType, result.Identities.ElementAt(1).AuthenticationType);
+        }
+
+        [Fact]
+        public void Should_serialize_and_deserialize_null_principal()
+        {
+            ClaimsPrincipal value = null;
+
+            value.SerializeAndDeserialize(new ClaimsPrincipalConverter());
+        }
+    }
+}

tests/Squidex.Infrastructure.Tests/Json/InstantConverterTests.cs

@@ -22,5 +22,21 @@ namespace Squidex.Infrastructure.Json
 
             value.SerializeAndDeserialize(new InstantConverter());
         }
+
+        [Fact]
+        public void Should_serialize_and_deserialize_nullable_with_value()
+        {
+            Instant? value = Instant.FromDateTimeUtc(DateTime.UtcNow.Date);
+
+            value.SerializeAndDeserialize(new InstantConverter());
+        }
+
+        [Fact]
+        public void Should_serialize_and_deserialize_nullable_with_null()
+        {
+            Instant? value = null;
+
+            value.SerializeAndDeserialize(new InstantConverter());
+        }
     }
 }

tests/Squidex.Infrastructure.Tests/LanguageTests.cs

@@ -42,18 +42,6 @@ namespace Squidex.Infrastructure
             Assert.True(Language.AllLanguages.Count() > 100);
         }
 
-        [Fact]
-        public void Should_serialize_and_deserialize_null_language()
-        {
-            JsonHelper.SerializeAndDeserialize<Language>(null, new LanguageConverter());
-        }
-
-        [Fact]
-        public void Should_serialize_and_deserialize_valid_language()
-        {
-            Language.DE.SerializeAndDeserialize(new LanguageConverter());
-        }
-
         [Fact]
         public void Should_return_true_for_valid_language()
         {
@@ -120,5 +108,21 @@ namespace Squidex.Infrastructure
 
             Assert.Null(language);
         }
+
+        [Fact]
+        public void Should_serialize_and_deserialize_null_language()
+        {
+            Language value = null;
+
+            value.SerializeAndDeserialize(new LanguageConverter());
+        }
+
+        [Fact]
+        public void Should_serialize_and_deserialize_valid_language()
+        {
+            var value = Language.DE;
+
+            value.SerializeAndDeserialize(new LanguageConverter());
+        }
     }
 }

tests/Squidex.Infrastructure.Tests/NamedIdTests.cs

@@ -90,37 +90,49 @@ namespace Squidex.Infrastructure
         [Fact]
         public void Should_serialize_and_deserialize_null_guid_token()
         {
-            JsonHelper.SerializeAndDeserialize<NamedId<Guid>>(null, new NamedGuidIdConverter());
+            NamedId<Guid> value = null;
+
+            value.SerializeAndDeserialize(new NamedGuidIdConverter());
         }
 
         [Fact]
         public void Should_serialize_and_deserialize_valid_guid_token()
         {
-            new NamedId<Guid>(Guid.NewGuid(), "my-name").SerializeAndDeserialize(new NamedGuidIdConverter());
+            var value = new NamedId<Guid>(Guid.NewGuid(), "my-name");
+
+            value.SerializeAndDeserialize(new NamedGuidIdConverter());
         }
 
         [Fact]
         public void Should_serialize_and_deserialize_null_long_token()
         {
-            JsonHelper.SerializeAndDeserialize<NamedId<long>>(null, new NamedLongIdConverter());
+            NamedId<long> value = null;
+
+            value.SerializeAndDeserialize(new NamedLongIdConverter());
         }
 
         [Fact]
         public void Should_serialize_and_deserialize_valid_long_token()
         {
-            new NamedId<long>(123, "my-name").SerializeAndDeserialize(new NamedLongIdConverter());
+            var value = new NamedId<long>(123, "my-name");
+
+            value.SerializeAndDeserialize(new NamedLongIdConverter());
         }
 
         [Fact]
         public void Should_serialize_and_deserialize_null_string_token()
         {
-            JsonHelper.SerializeAndDeserialize<NamedId<string>>(null, new NamedStringIdConverter());
+            NamedId<string> value = null;
+
+            value.SerializeAndDeserialize(new NamedStringIdConverter());
         }
 
         [Fact]
         public void Should_serialize_and_deserialize_valid_string_token()
         {
-            new NamedId<string>(Guid.NewGuid().ToString(), "my-name").SerializeAndDeserialize(new NamedStringIdConverter());
+            var value = new NamedId<string>(Guid.NewGuid().ToString(), "my-name");
+
+            value.SerializeAndDeserialize(new NamedStringIdConverter());
         }
 
         [Fact]

tests/Squidex.Infrastructure.Tests/RefTokenTests.cs

@@ -108,13 +108,17 @@ namespace Squidex.Infrastructure
         [Fact]
         public void Should_serialize_and_deserialize_null_token()
         {
-            JsonHelper.SerializeAndDeserialize<RefToken>(null, new RefTokenConverter());
+            RefToken value = null;
+
+            value.SerializeAndDeserialize(new RefTokenConverter());
         }
 
         [Fact]
         public void Should_serialize_and_deserialize_valid_token()
         {
-            RefToken.Parse("client:client1").SerializeAndDeserialize(new RefTokenConverter());
+            var value = RefToken.Parse("client:client1");
+
+            value.SerializeAndDeserialize(new RefTokenConverter());
         }
     }
 }

tests/Squidex.Infrastructure.Tests/TestHelpers/JsonHelper.cs

@@ -30,6 +30,13 @@ namespace Squidex.Infrastructure.TestHelpers
         }
 
         public static void SerializeAndDeserialize<T>(this T value, JsonConverter converter)
+        {
+            var output = SerializeAndDeserializeAndReturn(value, converter);
+
+            Assert.Equal(value, output);
+        }
+
+        public static T SerializeAndDeserializeAndReturn<T>(this T value, JsonConverter converter)
         {
             var serializerSettings = new JsonSerializerSettings();
 
@@ -39,7 +46,7 @@ namespace Squidex.Infrastructure.TestHelpers
             var result = JsonConvert.SerializeObject(Tuple.Create(value), serializerSettings);
             var output = JsonConvert.DeserializeObject<Tuple<T>>(result, serializerSettings);
 
-            Assert.Equal(value, output.Item1);
+            return output.Item1;
         }
 
         public static void DoesNotDeserialize<T>(string value, JsonConverter converter)