feat: add DeleteMessageBatchAsync method and MessageBatchDeleteResponse model with tests

tests/AnthropicClient.Tests/Integration/AnthropicApiClientTests.cs

@@ -1904,4 +1904,28 @@ public class AnthropicApiClientTests : IntegrationTest
     result.Error.Should().BeOfType<AnthropicError>();
     result.Error.Error.Should().BeOfType<InvalidRequestError>();
   }
+
+  [Fact]
+  public async Task DeleteMessageBatchAsync_WhenCalled_ItShouldReturnDeletionResponse()
+  {
+    var batchId = "msgbatch_013Zva2CMHLNnXjNJJKqJ2EF";
+
+    _mockHttpMessageHandler
+      .WhenDeleteMessageBatchRequest(batchId)
+      .Respond(
+        HttpStatusCode.OK,
+        "application/json",
+        @"{
+            ""id"": ""msgbatch_013Zva2CMHLNnXjNJJKqJ2EF"",
+            ""type"": ""message_batch_deleted""
+          }"
+      );
+
+    var result = await Client.DeleteMessageBatchAsync(batchId);
+
+    result.IsSuccess.Should().BeTrue();
+    result.Value.Should().BeOfType<MessageBatchDeleteResponse>();
+    result.Value.Id.Should().Be(batchId);
+    result.Value.Type.Should().Be("message_batch_deleted");
+  }
 }

tests/AnthropicClient.Tests/Integration/IntegrationTest.cs

@@ -97,4 +97,10 @@ public static class MockHttpMessageHandlerExtensions
     return mockHttpMessageHandler
       .SetupBaseRequest(HttpMethod.Post, $"{MessageBatchesEndpoint}/{batchId}/cancel");
   }
+
+  public static MockedRequest WhenDeleteMessageBatchRequest(this MockHttpMessageHandler mockHttpMessageHandler, string batchId)
+  {
+    return mockHttpMessageHandler
+      .SetupBaseRequest(HttpMethod.Delete, $"{MessageBatchesEndpoint}/{batchId}");
+  }
 }

tests/AnthropicClient.Tests/Unit/Models/MessageBatchDeleteResponseTests.cs

@@ -0,0 +1,41 @@
+namespace AnthropicClient.Tests.Unit.Models;
+
+public class MessageBatchDeleteResponseTests : SerializationTest
+{
+  private const string SampleJson = @"{
+    ""id"": ""test-id"",
+    ""type"": ""test-type""
+  }";
+
+  [Fact]
+  public void Constructor_WhenCalled_ItShouldReturnAnInstanceWithPropertiesSet()
+  {
+    var result = new MessageBatchDeleteResponse();
+
+    result.Id.Should().BeEmpty();
+    result.Type.Should().BeEmpty();
+  }
+
+  [Fact]
+  public void JsonSerialization_WhenSerialized_ItShouldHaveExpectedShape()
+  {
+    var result = new MessageBatchDeleteResponse
+    {
+      Id = "test-id",
+      Type = "test-type"
+    };
+
+    var json = Serialize(result);
+
+    JsonAssert.Equal(SampleJson, json);
+  }
+
+  [Fact]
+  public void JsonDeserialization_WhenDeserialized_ItShouldHaveExpectedValues()
+  {
+    var result = Deserialize<MessageBatchDeleteResponse>(SampleJson);
+
+    result!.Id.Should().Be("test-id");
+    result.Type.Should().Be("test-type");
+  }
+}