Refactor response configuration (#168)

Configuring responses now has a complete overhaul. By using IResponse, it is now possible to create delayed and sequenced responses and in general it is more flexible.
All old response configuration options are deprecated as a result, so tests that use these configurations have to be refactored.

Author: dnperfors

CHANGELOG.md

@@ -5,10 +5,22 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [0.8] - Unplanned
+### Deprecated
+- `TestableHttpMessageHandler.SimulateTimeout` is deprecated, and can be replaced with `RespondWith(Responses.Timeout())`.
+- `TestableHttpMessageHandler.RespondWith(Func<HttpRequestMessage, HttpResponseMessage>)` had been deprecated, it's functionality is replaced by IResponse.
+- `RespondWith(this TestableHttpMessageHandler, HttpResponseMessage)` has been deprecated, the response is modified with every call, so it doesn't work reliably and is different from how HttpClientHandler works, which creates a HttpResponseMessage for every request.
+- `HttpResponseMessageBuilder` and `RespondWith(this TestableHttpMessageHandler, HttpResponseMessageBuilder)` has been deprecated, it's functionality can be replaced with ConfiguredResponse or a custom IResponse.
 
 ### Added
 - `CreateClient` now accepts `DelegateHandlers` in order to chain Handlers. The InnerHandler property of each handler is set automatically and the `TestableHttpMessageHandler` is automatically set as the last handler. This is showcased with Polly in the integration tests.
 - Added support for .NET Framework 4.6.2, .NET Framework 4.7 and .NET Framework 4.8 by running the tests against these versions.
+- Added several `Responses`, including `Delayed`, `Timeout`, `Configured`, `Sequenced`, `StatusCode` and `Json`. These responses can now be used inside the `RespondWith`.
+
+### Changed
+- `TestableHttpClient` now works with the `Responses` class, making it easier to configure responses.
+- When `HttpResponseMessage.Content` is null after `IResponse.ExecuteAsync` was called, an empty `StringContent` is added (Up until .NET 6.0, since Content is always filled there).
+- The `HttpRequestMessage` is always added to the response, which is now possible, since we no longer allow reusing responses.
+- Added `ConfigureAwait(false)` to all calls, since we now use async/await in the library.
 
 ## [0.7] - 2022-09-22
 ### Changed

global.json

@@ -0,0 +1,7 @@
+{
+  "sdk": {
+    "version": "6.0.203",
+    "allowPrerelease": false,
+    "rollForward": "latestMajor"
+  }
+}

src/TestableHttpClient/CompilerTypes.cs

@@ -0,0 +1,11 @@
+// This file is used to register types that are normally generated by the compiler
+// but aren't generated for older versions of .NET
+#if !NET6_0_OR_GREATER
+using System.ComponentModel;
+
+namespace System.Runtime.CompilerServices;
+
+// This class is used for init setters, which are introduced in .NET 6
+[EditorBrowsable(EditorBrowsableState.Never)]
+internal static class IsExternalInit { }
+#endif

src/TestableHttpClient/HttpResponseContext.cs

@@ -0,0 +1,22 @@
+namespace TestableHttpClient;
+
+/// <summary>
+/// This class contains contextual information for generating responses.
+/// </summary>
+public class HttpResponseContext
+{
+    public HttpResponseContext(HttpRequestMessage httpRequestMessage, HttpResponseMessage httpResponseMessage)
+    {
+        HttpRequestMessage = httpRequestMessage;
+        HttpResponseMessage = httpResponseMessage;
+    }
+
+    /// <summary>
+    /// The request message that is send by the HttpClient.
+    /// </summary>
+    public HttpRequestMessage HttpRequestMessage { get; }
+    /// <summary>
+    /// The response message that will be send back to the HttpClient.
+    /// </summary>
+    public HttpResponseMessage HttpResponseMessage { get; }
+}

src/TestableHttpClient/HttpResponseMessageBuilder.cs

@@ -6,12 +6,23 @@ namespace TestableHttpClient;
 /// This class helps creating an <see cref="HttpResponseMessage"/> using a fluent interface.
 /// </summary>
 [SuppressMessage("Design", "CA1001:Types that own disposable fields should be disposable", Justification = "The HttpResponseMessage is only created and passed to the consumer.")]
+[Obsolete("Use ConfiguredResponse or a custom IResponse instead.")]
 public sealed class HttpResponseMessageBuilder
 {
-    private readonly HttpResponseMessage httpResponseMessage = new HttpResponseMessage
+    private readonly HttpResponseMessage httpResponseMessage;
+
+    public HttpResponseMessageBuilder()
+    {
+        httpResponseMessage = new HttpResponseMessage
+        {
+            Content = new StringContent("")
+        };
+    }
+
+    internal HttpResponseMessageBuilder(HttpResponseMessage httpResponseMessage)
     {
-        Content = new StringContent("")
-    };
+        this.httpResponseMessage = httpResponseMessage ?? throw new ArgumentNullException(nameof(httpResponseMessage));
+    }
 
     /// <summary>
     /// Specifies the version of the response.

src/TestableHttpClient/IResponse.cs

@@ -0,0 +1,15 @@
+namespace TestableHttpClient;
+
+/// <summary>
+/// This interface describes how responses should be implemented.
+/// </summary>
+public interface IResponse
+{
+    /// <summary>
+    /// Execute the response and fill the HttpResponseMessage on the HttpResponseContext.
+    /// </summary>
+    /// <param name="context">The context for this request.</param>
+    /// <param name="cancellationToken">The cancellationToken.</param>
+    /// <returns></returns>
+    Task ExecuteAsync(HttpResponseContext context, CancellationToken cancellationToken);
+}

src/TestableHttpClient/IResponsesExtensions.cs

@@ -0,0 +1,10 @@
+using System.Diagnostics.CodeAnalysis;
+
+namespace TestableHttpClient;
+
+/// <summary>
+/// Provides an interface for registering external methods that provide
+/// custom <see cref="IResponse" /> instances.
+/// </summary>
+[SuppressMessage("Design", "CA1040:Avoid empty interfaces", Justification = "Used for extending Responses class")]
+public interface IResponsesExtensions { }

src/TestableHttpClient/Response/BuilderResponse.cs

@@ -0,0 +1,20 @@
+namespace TestableHttpClient.Response;
+
+[Obsolete("Use ConfiguredResponse or a custom IResponse instead.")]
+internal class BuilderResponse : IResponse
+{
+    private readonly Action<HttpResponseMessageBuilder> httpResponseMessageBuilderAction;
+
+    internal BuilderResponse(Action<HttpResponseMessageBuilder> httpResponseMessageBuilderAction)
+    {
+        this.httpResponseMessageBuilderAction = httpResponseMessageBuilderAction ?? throw new ArgumentNullException(nameof(httpResponseMessageBuilderAction));
+    }
+
+    public Task ExecuteAsync(HttpResponseContext context, CancellationToken cancellationToken)
+    {
+        HttpResponseMessageBuilder builder = new(context.HttpResponseMessage);
+        httpResponseMessageBuilderAction(builder);
+
+        return Task.CompletedTask;
+    }
+}

src/TestableHttpClient/Response/ConfiguredResponse.cs

@@ -0,0 +1,19 @@
+namespace TestableHttpClient.Response;
+
+internal class ConfiguredResponse : IResponse
+{
+    private readonly IResponse innerResponse;
+    private readonly Action<HttpResponseMessage> configureResponse;
+
+    public ConfiguredResponse(IResponse response, Action<HttpResponseMessage> configureResponse)
+    {
+        innerResponse = response ?? throw new ArgumentNullException(nameof(response));
+        this.configureResponse = configureResponse ?? throw new ArgumentNullException(nameof(configureResponse));
+    }
+
+    public async Task ExecuteAsync(HttpResponseContext context, CancellationToken cancellationToken)
+    {
+        await innerResponse.ExecuteAsync(context, cancellationToken).ConfigureAwait(false);
+        configureResponse(context.HttpResponseMessage);
+    }
+}

src/TestableHttpClient/Response/DelayedResponse.cs

@@ -0,0 +1,19 @@
+namespace TestableHttpClient.Response;
+
+internal class DelayedResponse : IResponse
+{
+    private readonly IResponse delayedResponse;
+    private readonly TimeSpan delay;
+
+    public DelayedResponse(IResponse delayedResponse, TimeSpan delay)
+    {
+        this.delayedResponse = delayedResponse ?? throw new ArgumentNullException(nameof(delayedResponse));
+        this.delay = delay;
+    }
+
+    public async Task ExecuteAsync(HttpResponseContext context, CancellationToken cancellationToken)
+    {
+        await Task.Delay(delay, cancellationToken).ConfigureAwait(false);
+        await delayedResponse.ExecuteAsync(context, cancellationToken).ConfigureAwait(false);
+    }
+}