A:初版

test/NetClient.Test/TestDoubles/TestJsonSerializer.cs

@@ -0,0 +1,25 @@
+using System.IO;
+using System.Text.Json;
+using System.Threading;
+using System.Threading.Tasks;
+using NetClient.Abstractions;
+
+namespace NetClient.Test.TestDoubles;
+
+public sealed class TestJsonSerializer : IHttpContentSerializer
+{
+    private readonly JsonSerializerOptions _options;
+
+    public TestJsonSerializer(JsonSerializerOptions? options = null)
+    {
+        _options = options ?? new JsonSerializerOptions(JsonSerializerDefaults.Web);
+    }
+
+    public string ContentType => "application/json";
+
+    public Task SerializeAsync<T>(Stream stream, T? value, CancellationToken cancellationToken = default)
+        => JsonSerializer.SerializeAsync(stream, value, _options, cancellationToken);
+
+    public Task<T?> DeserializeAsync<T>(Stream stream, CancellationToken cancellationToken = default)
+        => JsonSerializer.DeserializeAsync<T>(stream, _options, cancellationToken).AsTask();
+}