A mock response for testing HttpContext.Response.

ReadMe.md

Usage

[TestMethod]
public async Task Invoke_AddResopnseHeaders_ResponseHeaderExists() {
    // ARRANGE
    const string expectedHeaderValue = "SomeValue";
    
    var respFeature = new MockResponseFeature();
    var ctx = new DefaultHttpContext();
    ctx.Features.Set<IHttpResponseFeature>(feature);

    RequestDelegate next = async (ctx) => {
        await respFeature.InvokeCallBack();
    };

    var alterResponseMiddleware = new AlterResponseMiddleware(next);

    // ACT
    await alterResponseMiddleware.Invoke(context);

    // ASSERT
    var response = ctx.Response;
    Assert.True(response.Headers.TryGetValues("X-Your-Header", out var expectedHeader));
    Assert.Equals(expectedHeaderValue, expectedHeader.FirstOrDefault()
}

MockResponseFeature.cs

using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Http.Features;

using System;
using System.Diagnostics.CodeAnalysis;
using System.IO;
using System.Threading.Tasks;

namespace Starbucks.CustomerEngagement.Serilog.Enrichers.Tests
{
    [ExcludeFromCodeCoverage]
    sealed public class MockResponseFeature : IHttpResponseFeature
    {
        public Stream Body { get; set; }

        public bool HasStarted { get { return hasStarted; } }

        public IHeaderDictionary Headers { get; set; }

        public string ReasonPhrase { get; set; }

        public int StatusCode { get; set; }

        public void OnCompleted(Func<object, Task> callback, object state)
        {
        }

        public void OnStarting(Func<object, Task> callback, object state)
        {
            this.callback = callback;
            this.state = state;
        }

        bool hasStarted = false;
        Func<object, Task> callback;
        object state;

        public Task InvokeCallBack()
        {
            hasStarted = true;
            return callback(state);
        }
    }
}