Dynamic schema creation example

test/GraphQL.Conventions.Tests/Adapters/Engine/DynamicConstructionTests.cs

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+using System.Reflection;
+using System.Threading.Tasks;
+using GraphQL;
+using GraphQL.Conventions.Adapters;
+using GraphQL.Conventions.Tests.Templates;
+using GraphQL.Conventions.Tests.Templates.Extensions;
+using GraphQL.Conventions.Types.Resolution;
+using GraphQL.Resolvers;
+using GraphQL.Types;
+using GraphQL.Utilities;
+using Newtonsoft.Json;
+using Xunit;
+
+namespace GraphQL.Conventions.Tests.Adapters.Engine
+{
+    public class DynamicConstructionTests : TestBase
+    {
+        [Fact]
+        public async Task Can_Construct_And_Describe_Schema_With_Dynamic_Queries()
+        {
+            var typeAdapter = new GraphTypeAdapter();
+            var typeResolver = new TypeResolver();
+
+            var userRepositoryInterface = GetGraphType(typeAdapter, typeResolver, typeof(IUserRepository).GetTypeInfo());
+            var userRepositoryType = GetGraphType(typeAdapter, typeResolver, typeof(UserRepository).GetTypeInfo());
+            var userType = GetGraphType(typeAdapter, typeResolver, typeof(User).GetTypeInfo());
+
+            var schema = new Schema
+            {
+                Query = new ObjectGraphType { Name = "Query" }
+            };
+
+            schema.RegisterTypes(userType, userRepositoryInterface, userRepositoryType);
+
+            schema.Query.AddField(new FieldType
+            {
+                Name = "users",
+                ResolvedType = userRepositoryType,
+                Resolver = new CustomResolver(new UserRepository()),
+            });
+
+            schema.ResolveType = (t) =>
+            {
+                if (t == typeof(IUserRepository))
+                {
+                    return userRepositoryInterface;
+                }
+                if (t == typeof(UserRepository))
+                {
+                    return userRepositoryType;
+                }
+                if (t == typeof(User))
+                {
+                    return userType;
+                }
+                return null;
+            };
+
+            var schemaDescription = new SchemaPrinter(schema).Print();
+            schemaDescription.ShouldEqualWhenReformatted(@"
+            interface IUserRepository {
+                getUserById(id: String): User
+            }
+            type Query {
+                users: UserRepository
+            }
+            type User {
+                id: String
+                name: String
+            }
+            type UserRepository implements IUserRepository {
+                getUserById(id: String): User
+            }
+            ");
+
+            var executer = new DocumentExecuter();
+            var result = await executer.ExecuteAsync(schema, null, "{ users { getUserById(id: \"1\") { id name } } }", null);
+            result.Errors.ShouldEqual(null);
+            JsonConvert.SerializeObject(result.Data).ShouldEqual("{\"users\":{\"getUserById\":{\"id\":\"1\",\"name\":\"User #1\"}}}");
+        }
+
+        private IGraphType GetGraphType(GraphTypeAdapter typeAdapter, TypeResolver typeResolver, TypeInfo typeInfo)
+        {
+            var graphTypeInfo = typeResolver.DeriveType(typeInfo);
+            return typeAdapter.DeriveType(graphTypeInfo);
+        }
+
+        class CustomResolver : IFieldResolver
+        {
+            private readonly UserRepository _userRepository;
+
+            public CustomResolver(UserRepository userRepository)
+            {
+                _userRepository = userRepository;
+            }
+
+            public object Resolve(ResolveFieldContext context) =>
+                _userRepository;
+        }
+
+        class User
+        {
+            public string Id { get; set; }
+
+            public string Name { get; set; }
+        }
+
+        interface IUserRepository
+        {
+            User GetUserById(string id);
+        }
+
+        class UserRepository : IUserRepository
+        {
+            public User GetUserById(string id) =>
+                new User
+                {
+                    Id = id,
+                    Name = $"User #{id}",
+                };
+        }
+    }
+}