Avanade · chullybun · Dec 4, 2025 · Dec 4, 2025
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -2,6 +2,11 @@
 
 Represents the **NuGet** versions.
 
+## v5.8.0
+- *Enhancement:* Extended the `MockHttpClientResponse.With*` methods to support optional _media type_ parameter to enable specification of the `Content-Type` header value.
+- *Enhancement:* Added `HttpResponseMessageAssertor.AssertContentTypeProblemJson` to enable asserting that the content type is `application/problem+json`.
+- *Fixed:* `HttpResponseMessageAssertor<TValue>.Value` no longer asserts the content type as `application/json` by default as this could not be overridden; this should be asserted explicitly using `AssertContentType()`, `AssertContentTypeJson()`, `AssertContentTypeProblemJson`, etc.
+
 ## v5.7.0
 - *Enhancement:* Added `.NET10.0` support to all `UnitTestEx` packages.
 - *Enhancement:* Added `AssertNoNamedHeader` to the `HttpResponseMessageAssertor` to enable asserting that a named header is not present in the response.

diff --git a/Common.targets b/Common.targets
@@ -1,6 +1,6 @@
 <Project>
 	<PropertyGroup>
-		<Version>5.7.0</Version>
+		<Version>5.8.0</Version>
 		<LangVersion>preview</LangVersion>
 		<Authors>Avanade</Authors>
 		<Company>Avanade</Company>

diff --git a/src/UnitTestEx.Azure.Functions/Azure/Functions/FunctionTesterBase.cs b/src/UnitTestEx.Azure.Functions/Azure/Functions/FunctionTesterBase.cs
@@ -196,7 +196,10 @@ protected override void ResetHost()
                 {
                     _host.Dispose();
                     _host = null;
-                    Implementor.WriteLine("The underlying UnitTestEx 'FunctionTester' Host has been reset.");
+                    Implementor.WriteLine("");
+                    Implementor.WriteLine("** The underlying UnitTestEx 'FunctionTester' Host has been reset. **");
+                    Implementor.WriteLine("");
+
                 }
             }
         }

diff --git a/src/UnitTestEx/AspNetCore/ApiTesterBase.cs b/src/UnitTestEx/AspNetCore/ApiTesterBase.cs
@@ -100,7 +100,9 @@ protected override void ResetHost()
                 {
                     _waf.Dispose();
                     _waf = null;
-                    Implementor.WriteLine("The underlying UnitTestEx 'ApiTester' Host has been reset.");
+                    Implementor.WriteLine("");
+                    Implementor.WriteLine("** The underlying UnitTestEx 'ApiTester' Host has been reset. **");
+                    Implementor.WriteLine("");
                 }
             }
         }
@@ -180,11 +182,8 @@ protected virtual void Dispose(bool disposing)
             if (_disposed)
                 return;
 
-            if (_waf != null)
-            {
-                _waf.Dispose();
-                _waf = null;
-            }
+            _waf?.Dispose();
+            _waf = null;
 
             _disposed = true;
         }

diff --git a/src/UnitTestEx/Assertors/HttpResponseMessageAssertorBaseT.cs b/src/UnitTestEx/Assertors/HttpResponseMessageAssertorBaseT.cs
@@ -63,6 +63,12 @@ public TSelf Assert(HttpStatusCode statusCode, string? content)
         /// <returns>The <see cref="HttpResponseMessageAssertorBase{TSelf}"/> instance to support fluent-style method-chaining.</returns>
         public TSelf AssertContentTypeJson() => AssertContentType(MediaTypeNames.Application.Json);
 
+        /// <summary>
+        /// Asserts that the <see cref="HttpResponseMessageAssertorBase.Response"/> content type is '<c>application/problem+json</c>'.
+        /// </summary>
+        /// <returns>The <see cref="HttpResponseMessageAssertorBase{TSelf}"/> instance to support fluent-style method-chaining.</returns>
+        public TSelf AssertContentTypeProblemJson() => AssertContentType("application/problem+json");
+
         /// <summary>
         /// Asserts that the <see cref="HttpResponseMessageAssertorBase.Response"/> content type is <see cref="MediaTypeNames.Text.Plain"/>.
         /// </summary>
@@ -187,6 +193,18 @@ public TSelf AssertETagHeader(System.Net.Http.Headers.EntityTagHeaderValue expec
         /// <returns>The <see cref="HttpResponseMessageAssertorBase{TSelf}"/> instance to support fluent-style method-chaining.</returns>
         public TSelf AssertForbidden() => Assert(HttpStatusCode.Forbidden);
 
+        /// <summary>
+        /// Asserts that the <see cref="HttpResponseMessageAssertorBase.Response"/> is a <see cref="HttpStatusCode.InternalServerError"/>.
+        /// </summary>
+        /// <returns>The <see cref="HttpResponseMessageAssertorBase{TSelf}"/> instance to support fluent-style method-chaining.</returns>
+        public TSelf AssertInternalServerError() => Assert(HttpStatusCode.InternalServerError);
+
+        /// <summary>
+        /// Asserts that the <see cref="HttpResponseMessageAssertorBase.Response"/> is a <see cref="HttpStatusCode.ServiceUnavailable"/>.
+        /// </summary>
+        /// <returns>The <see cref="HttpResponseMessageAssertorBase{TSelf}"/> instance to support fluent-style method-chaining.</returns>
+        public TSelf AssertServiceUnavailable() => Assert(HttpStatusCode.ServiceUnavailable);
+
         /// <summary>
         /// Asserts that the <see cref="HttpResponseMessageAssertorBase.Response"/> contains the expected error <paramref name="messages"/>.
         /// </summary>

diff --git a/src/UnitTestEx/Assertors/HttpResponseMessageAssertorT.cs b/src/UnitTestEx/Assertors/HttpResponseMessageAssertorT.cs
@@ -39,13 +39,14 @@ internal HttpResponseMessageAssertor(HttpResponseMessageAssertor assertor) : thi
         /// Gets the response content as the deserialized JSON value.
         /// </summary>
         /// <returns>The result value.</returns>
+        /// <remarks>The corresponding content type is not asserted, where this is required then <see cref="HttpResponseMessageAssertorBase.GetValue{T}(string?)"/> should be used.</remarks>
         public TValue? Value
         {
             get
             {
                 if (!_valueIsDeserialized)
                 {
-                    _value = GetValue<TValue>();
+                    _value = GetValue<TValue>(null);
                     _valueIsDeserialized = true;
                 }
 
@@ -60,7 +61,7 @@ public TValue? Value
         /// <returns>The <see cref="HttpResponseMessageAssertor{TValue}"/> to support fluent-style method-chaining.</returns>
         public HttpResponseMessageAssertor<TValue> AssertLocationHeader(Func<TValue?, string> expected)
         {
-            Implementor.AssertAreEqual(expected?.Invoke(GetValue<TValue>()), Response.Headers?.Location?.ToString(), $"Expected and Actual HTTP Response Header '{HeaderNames.Location}' values are not equal.");
+            Implementor.AssertAreEqual(expected?.Invoke(Value), Response.Headers?.Location?.ToString(), $"Expected and Actual HTTP Response Header '{HeaderNames.Location}' values are not equal.");
             return this;
         }
 
@@ -71,7 +72,7 @@ public HttpResponseMessageAssertor<TValue> AssertLocationHeader(Func<TValue?, st
         /// <returns>The <see cref="HttpResponseMessageAssertor{TValue}"/> to support fluent-style method-chaining.</returns>
         public HttpResponseMessageAssertor<TValue> AssertLocationHeader(Func<TValue?, Uri> expectedUri)
         {
-            Implementor.AssertAreEqual(expectedUri?.Invoke(GetValue<TValue>()), Response.Headers?.Location, $"Expected and Actual HTTP Response Header '{HeaderNames.Location}' values are not equal.");
+            Implementor.AssertAreEqual(expectedUri?.Invoke(Value), Response.Headers?.Location, $"Expected and Actual HTTP Response Header '{HeaderNames.Location}' values are not equal.");
             return this;
         }
 
@@ -100,7 +101,7 @@ public HttpResponseMessageAssertor<TValue> AssertLocationHeaderContains(string e
         /// <param name="expected">The expected string.</param>
         /// <returns>The <see cref="HttpResponseMessageAssertor{TValue}"/> to support fluent-style method-chaining.</returns>
         public HttpResponseMessageAssertor<TValue> AssertLocationHeaderContains(Func<TValue?, string> expected)
-            => AssertLocationHeaderContains(expected?.Invoke(GetValue<TValue>())!);
+            => AssertLocationHeaderContains(expected?.Invoke(Value)!);
 
         /// <summary>
         /// Asserts that the <see cref="HttpResponseMessageAssertorBase.Response"/> matches the <paramref name="expectedValue"/>.

diff --git a/src/UnitTestEx/Generic/GenericTesterCore.cs b/src/UnitTestEx/Generic/GenericTesterCore.cs
@@ -155,7 +155,9 @@ protected override void ResetHost()
                 {
                     _host.Dispose();
                     _host = null;
-                    Implementor.WriteLine("The underlying UnitTestEx 'GenericTester' Host has been reset.");
+                    Implementor.WriteLine("");
+                    Implementor.WriteLine("** The underlying UnitTestEx 'GenericTester' Host has been reset. **");
+                    Implementor.WriteLine("");
                 }
             }
         }

diff --git a/src/UnitTestEx/Mocking/MockHttpClient.cs b/src/UnitTestEx/Mocking/MockHttpClient.cs
@@ -187,7 +187,7 @@ public MockHttpClient WithoutHttpMessageHandlers()
         }
 
         /// <summary>
-        /// Specifies that the configurations for the <see cref="GetHttpClient()"/> aer to be used.
+        /// Specifies that the configurations for the <see cref="GetHttpClient()"/> are to be used.
         /// </summary>
         /// <returns>The <see cref="MockHttpClient"/> to support fluent-style method-chaining.</returns>
         /// <remarks>By default the <see cref="GetHttpClient()"/> configurations are not invoked.</remarks>
@@ -428,7 +428,6 @@ public void Add(MockHttpClient client)
                         (res ?? new()).Add(seq.Respond());
                     }
                 });
-
             }
         }
 

diff --git a/src/UnitTestEx/Mocking/MockHttpClientResponse.cs b/src/UnitTestEx/Mocking/MockHttpClientResponse.cs
@@ -182,32 +182,35 @@ public void With(HttpContent? content = null, HttpStatusCode? statusCode = null,
         /// </summary>
         /// <param name="content">The <see cref="string"/> content.</param>
         /// <param name="statusCode">The optional <see cref="HttpStatusCode"/> (defaults to <see cref="HttpStatusCode.OK"/>).</param>
+        /// <param name="mediaType">The optional media type (defaults to <see cref="MediaTypeNames.Text.Plain"/>).</param>
         /// <param name="response">The optional action to enable additional configuration of the <see cref="HttpResponseMessage"/>.</param>
-        public void With(string content, HttpStatusCode? statusCode = null, Action<HttpResponseMessage>? response = null) => With(new StringContent(content ?? throw new ArgumentNullException(nameof(content))), statusCode, response);
+        public void With(string content, HttpStatusCode? statusCode = null, string? mediaType = MediaTypeNames.Text.Plain, Action<HttpResponseMessage>? response = null) => With(new StringContent(content ?? throw new ArgumentNullException(nameof(content)), null, mediaType!), statusCode, response);
 
         /// <summary>
         /// Provides the mocked response using the <paramref name="value"/> which will be automatically converted to JSON content.
         /// </summary>
         /// <typeparam name="T">The value <see cref="Type"/>.</typeparam>
-        /// <param name="value">The value to convert to <see cref="MediaTypeNames.Application.Json"/> content.</param>
+        /// <param name="value">The value to convert to JSON content.</param>
         /// <param name="statusCode">The optional <see cref="HttpStatusCode"/> (defaults to <see cref="HttpStatusCode.OK"/>).</param>
+        /// <param name="mediaType">The optional media type (defaults to <see cref="MediaTypeNames.Application.Json"/>).</param>
         /// <param name="response">The optional action to enable additional configuration of the <see cref="HttpResponseMessage"/>.</param>
-        public void WithJson<T>(T value, HttpStatusCode? statusCode = null, Action<HttpResponseMessage>? response = null) => WithJson(_clientRequest.JsonSerializer.Serialize(value, JsonWriteFormat.None), statusCode, response);
+        public void WithJson<T>(T value, HttpStatusCode? statusCode = null, string? mediaType = MediaTypeNames.Application.Json, Action<HttpResponseMessage>? response = null) => WithJson(_clientRequest.JsonSerializer.Serialize(value, JsonWriteFormat.None), statusCode, mediaType, response);
 
         /// <summary>
         /// Provides the mocked response using the <paramref name="json"/> formatted string as the content.
         /// </summary>
         /// <param name="json">The <see cref="MediaTypeNames.Application.Json"/> content.</param>
         /// <param name="statusCode">The optional <see cref="HttpStatusCode"/> (defaults to <see cref="HttpStatusCode.OK"/>).</param>
+        /// <param name="mediaType">The optional media type (defaults to <see cref="MediaTypeNames.Application.Json"/>).</param>
         /// <param name="response">The optional action to enable additional configuration of the <see cref="HttpResponseMessage"/>.</param>
 #if NET7_0_OR_GREATER
-        public void WithJson([StringSyntax(StringSyntaxAttribute.Json)] string json, HttpStatusCode? statusCode = null, Action<HttpResponseMessage>? response = null)
+        public void WithJson([StringSyntax(StringSyntaxAttribute.Json)] string json, HttpStatusCode? statusCode = null, string? mediaType = MediaTypeNames.Application.Json, Action<HttpResponseMessage>? response = null)
 #else
-        public void WithJson(string json, HttpStatusCode? statusCode = null, Action<HttpResponseMessage>? response = null)
+        public void WithJson(string json, HttpStatusCode? statusCode = null, string? mediaType = MediaTypeNames.Application.Json, Action<HttpResponseMessage>? response = null)
 #endif
         {
             var content = new StringContent(json ?? throw new ArgumentNullException(nameof(json)));
-            content.Headers.ContentType = MediaTypeHeaderValue.Parse(MediaTypeNames.Application.Json);
+            content.Headers.ContentType = MediaTypeHeaderValue.Parse(mediaType ?? MediaTypeNames.Application.Json);
             With(content, statusCode, response);
         }
 
@@ -217,21 +220,23 @@ public void WithJson(string json, HttpStatusCode? statusCode = null, Action<Http
         /// <typeparam name="TAssembly">The <see cref="Type"/> used to infer <see cref="Assembly"/> that contains the embedded resource.</typeparam>
         /// <param name="resourceName">The embedded resource name (matches to the end of the fully qualifed resource name).</param>
         /// <param name="statusCode">The optional <see cref="HttpStatusCode"/> (defaults to <see cref="HttpStatusCode.OK"/>).</param>
+        /// <param name="mediaType">The optional media type (defaults to <see cref="MediaTypeNames.Application.Json"/>).</param>
         /// <param name="response">The optional action to enable additional configuration of the <see cref="HttpResponseMessage"/>.</param>
-        public void WithJsonResource<TAssembly>(string resourceName, HttpStatusCode? statusCode = null, Action<HttpResponseMessage>? response = null)
-            => WithJsonResource(resourceName, statusCode, response, typeof(TAssembly).Assembly);
+        public void WithJsonResource<TAssembly>(string resourceName, HttpStatusCode? statusCode = null, string? mediaType = MediaTypeNames.Application.Json, Action<HttpResponseMessage>? response = null)
+            => WithJsonResource(resourceName, statusCode, mediaType, response, typeof(TAssembly).Assembly);
 
         /// <summary>
         /// Provides the mocked response using the JSON formatted embedded resource string as the content.
         /// </summary>
         /// <param name="resourceName">The embedded resource name (matches to the end of the fully qualifed resource name).</param>
         /// <param name="statusCode">The optional <see cref="HttpStatusCode"/> (defaults to <see cref="HttpStatusCode.OK"/>).</param>
+        /// <param name="mediaType">The optional media type (defaults to <see cref="MediaTypeNames.Application.Json"/>).</param>
         /// <param name="response">The optional action to enable additional configuration of the <see cref="HttpResponseMessage"/>.</param>
         /// <param name="assembly">The <see cref="Assembly"/> that contains the embedded resource; defaults to <see cref="Assembly.GetCallingAssembly"/>.</param>
-        public void WithJsonResource(string resourceName, HttpStatusCode? statusCode = null, Action<HttpResponseMessage>? response = null, Assembly? assembly = null)
+        public void WithJsonResource(string resourceName, HttpStatusCode? statusCode = null, string? mediaType = MediaTypeNames.Application.Json, Action<HttpResponseMessage>? response = null, Assembly? assembly = null)
         {
             using var sr = Resource.GetStream(resourceName, assembly ?? Assembly.GetCallingAssembly());
-            WithJson(sr.ReadToEnd(), statusCode, response);
+            WithJson(sr.ReadToEnd(), statusCode, mediaType, response);
         }
 
         /// <summary>