test: add implicit removal test

Author: maurei

src/Examples/JsonApiDotNetCoreExample/Models/Passport.cs

@@ -0,0 +1,11 @@
+using JsonApiDotNetCore.Models;
+
+namespace JsonApiDotNetCoreExample.Models
+{
+    public class Passport : Identifiable
+    {
+        public virtual int? SocialSecurityNumber { get; set; }
+        [HasOne("person")]
+        public virtual Person Person { get; set; }
+    }
+}

src/Examples/JsonApiDotNetCoreExample/Models/Person.cs

@@ -45,5 +45,9 @@ public Dictionary<string, object> GetMeta(IJsonApiContext context)
                 { "authors", new string[] { "Jared Nance" } }
             };
         }
+        public int? PassportId { get; set; }
+        [HasOne("passport")]
+        public virtual Passport Passport { get; set; }
+
     }
 }

src/JsonApiDotNetCore/Data/DefaultEntityRepository.cs

@@ -242,7 +242,6 @@ public virtual async Task<TEntity> UpdateAsync(TId id, TEntity entity)
                     }
                     else if (relationshipEntry.Key is HasOneAttribute hasOneAttribute)
                     {
-                        //var foreignkeyValue = relationshipValue.GetType().GetProperty(hasOneAttribute.IdentifiablePropertyName).GetValue(oldEntity);
                         hasOneAttribute.SetValue(oldEntity, relationshipValue);
                     }
                 }

test/JsonApiDotNetCoreExampleTests/Acceptance/Spec/UpdatingRelationshipsTests.cs

@@ -621,5 +621,52 @@ public async Task Can_Delete_Relationship_By_Patching_Relationship()
             Assert.Equal(HttpStatusCode.OK, response.StatusCode);
             Assert.Null(todoItemResult.Owner);
         }
+
+        [Fact]
+        public async Task Updating_ToOne_Relationship_With_Implicit_Remove()
+        {
+
+            // Arrange
+            var context = _fixture.GetService<AppDbContext>();
+            var passport = new Passport();
+            var person1 = _personFaker.Generate();
+            person1.Passport = passport;
+            var person2 = _personFaker.Generate();
+            context.People.AddRange(new List<Person>() { person1, person2 });
+            await context.SaveChangesAsync();
+
+            var content = new
+            {
+                data = new
+                {
+                    type = "people",
+                    id = person2.Id,
+                    relationships = new Dictionary<string, object>
+                    {
+                        { "passport", new
+                            {
+                                data = new { type = "passports", id = $"{person1.PassportId}" }
+                            }
+                        }
+                    }
+                }
+            };
+
+            var httpMethod = new HttpMethod("PATCH");
+            var route = $"/api/v1/people/{person2.Id}";
+            var request = new HttpRequestMessage(httpMethod, route);
+
+            string serializedContent = JsonConvert.SerializeObject(content);
+            request.Content = new StringContent(serializedContent);
+            request.Content.Headers.ContentType = new MediaTypeHeaderValue("application/vnd.api+json");
+
+            // Act
+            var response = await _fixture.Client.SendAsync(request);
+
+            // Assert
+            var body = await response.Content.ReadAsStringAsync();
+            Assert.True(HttpStatusCode.OK == response.StatusCode, $"{route} returned {response.StatusCode} status code with payload: {body}");
+
+        }
     }
 }