Add a test

Author: pranavkm

src/Mvc/Mvc.Core/test/DependencyInjection/ApiBehaviorOptionsSetupTest.cs

@@ -51,6 +51,31 @@ public void ProblemDetailsInvalidModelStateResponse_ReturnsBadRequestWithProblem
             Assert.Equal("https://tools.ietf.org/html/rfc7231#section-6.5.1", problemDetails.Type);
         }
 
+        [Fact]
+        public void ProblemDetailsInvalidModelStateResponse_UsesUserConfiguredLink()
+        {
+            // Arrange
+            var link = "http://mylink";
+            var actionContext = new ActionContext
+            {
+                HttpContext = new DefaultHttpContext { TraceIdentifier = "42" },
+            };
+
+            var factory = GetInvalidModelStateResponseFactory(options => options.ClientErrorMapping[400].Link = link);
+
+            // Act
+            var result = factory(actionContext);
+
+            // Assert
+            var badRequest = Assert.IsType<BadRequestObjectResult>(result);
+            Assert.Equal(new[] { "application/problem+json", "application/problem+xml" }, badRequest.ContentTypes.OrderBy(c => c));
+
+            var problemDetails = Assert.IsType<ValidationProblemDetails>(badRequest.Value);
+            Assert.Equal(400, problemDetails.Status);
+            Assert.Equal("One or more validation errors occurred.", problemDetails.Title);
+            Assert.Equal(link, problemDetails.Type);
+        }
+
         [Fact]
         public void ProblemDetailsInvalidModelStateResponse_SetsTraceId()
         {
@@ -92,12 +117,16 @@ public void ProblemDetailsInvalidModelStateResponse_SetsTraceIdFromRequest_IfAct
             Assert.Equal("42", problemDetails.Extensions["traceId"]);
         }
 
-        private static Func<ActionContext, IActionResult> GetInvalidModelStateResponseFactory()
+        private static Func<ActionContext, IActionResult> GetInvalidModelStateResponseFactory(Action<ApiBehaviorOptions> configure = null)
         {
             var options = new ApiBehaviorOptions();
             var setup = new ApiBehaviorOptionsSetup();
 
             setup.Configure(options);
+            if (configure != null)
+            {
+                configure(options);
+            }
 
             var factory = options.InvalidModelStateResponseFactory;
             return factory;