test(fetching): relationship request should ret null if unset

Issue #21 - 2 
Relationship requests should return null if the relationship has not been set

Author: jaredcnance

test/JsonApiDotNetCoreExampleTests/Acceptance/Spec/FetchingDataTests.cs

@@ -1,4 +1,3 @@
-using System;
 using System.Collections.Generic;
 using System.Net;
 using System.Net.Http;

test/JsonApiDotNetCoreExampleTests/Acceptance/Spec/FetchingRelationshipsTests.cs

@@ -0,0 +1,70 @@
+using System;
+using System.Collections.Generic;
+using System.Net;
+using System.Net.Http;
+using System.Threading.Tasks;
+using Bogus;
+using DotNetCoreDocs;
+using DotNetCoreDocs.Writers;
+using JsonApiDotNetCore.Models;
+using JsonApiDotNetCore.Serialization;
+using JsonApiDotNetCore.Services;
+using JsonApiDotNetCoreExample;
+using JsonApiDotNetCoreExample.Data;
+using JsonApiDotNetCoreExample.Models;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.TestHost;
+using Newtonsoft.Json;
+using Xunit;
+using Person = JsonApiDotNetCoreExample.Models.Person;
+
+namespace JsonApiDotNetCoreExampleTests.Acceptance.Spec
+{
+    [Collection("WebHostCollection")]
+    public class FetchingRelationshipsTests
+    {
+        private DocsFixture<Startup, JsonDocWriter> _fixture;
+        private IJsonApiContext _jsonApiContext;
+        private Faker<TodoItem> _todoItemFaker;
+
+        public FetchingRelationshipsTests(DocsFixture<Startup, JsonDocWriter> fixture)
+        {
+            _fixture = fixture;
+            _jsonApiContext = fixture.GetService<IJsonApiContext>();
+            _todoItemFaker = new Faker<TodoItem>()
+                .RuleFor(t => t.Description, f => f.Lorem.Sentence())
+                .RuleFor(t => t.Ordinal, f => f.Random.Number());
+        }
+
+        [Fact]
+        public async Task Request_UnsetRelationship_Returns_Null_DataObject()
+        {
+            // arrange
+            var context = _fixture.GetService<AppDbContext>();
+            var todoItem = _todoItemFaker.Generate();
+            context.TodoItems.Add(todoItem);
+            await context.SaveChangesAsync();
+
+            var builder = new WebHostBuilder()
+                .UseStartup<Startup>();
+
+            var httpMethod = new HttpMethod("GET");
+            var route = $"/api/v1/todo-items/{todoItem.Id}/owner";
+            var server = new TestServer(builder);
+            var client = server.CreateClient();
+            var request = new HttpRequestMessage(httpMethod, route);
+            var expectedBody = "{\"data\":null}";
+
+            // act
+            var response = await client.SendAsync(request);
+            var body = await response.Content.ReadAsStringAsync();
+
+            // assert
+            Assert.Equal(HttpStatusCode.OK, response.StatusCode);
+            Assert.Equal("application/vnd.api+json", response.Content.Headers.ContentType.ToString());
+            Assert.Equal(expectedBody, body);
+
+            context.Dispose();
+        }
+    }
+}