lightweight variant (#1)

Reviewed-on: #1
Co-authored-by: Aleksandr Neychev <alexnejchev73@gmail.com>

CursorLang.Tests.Shared/FakeHttp.cs

@@ -0,0 +1,40 @@
+using System.Net;
+using System.Text;
+
+namespace CursorLang.Tests.Shared;
+
+/// <summary>
+/// The network as the test writes it: the answer is decided here rather than
+/// by a repository somewhere.
+/// </summary>
+public sealed class FakeHttpHandler : HttpMessageHandler
+{
+    private readonly Func<HttpRequestMessage, HttpResponseMessage> _reply;
+
+    public FakeHttpHandler(Func<HttpRequestMessage, HttpResponseMessage> reply) => _reply = reply;
+
+    public List<HttpRequestMessage> Requests { get; } = [];
+
+    public static FakeHttpHandler Json(string json) => new(_ => new HttpResponseMessage(HttpStatusCode.OK)
+    {
+        Content = new StringContent(json, Encoding.UTF8, "application/json"),
+    });
+
+    public static FakeHttpHandler Status(HttpStatusCode status) =>
+        new(_ => new HttpResponseMessage(status));
+
+    public static FakeHttpHandler Bytes(byte[] content) => new(_ => new HttpResponseMessage(HttpStatusCode.OK)
+    {
+        Content = new ByteArrayContent(content),
+    });
+
+    public HttpClient CreateClient() => new(this);
+
+    protected override Task<HttpResponseMessage> SendAsync(
+        HttpRequestMessage request,
+        CancellationToken cancellationToken)
+    {
+        Requests.Add(request);
+        return Task.FromResult(_reply(request));
+    }
+}