diff --git a/tests/AnthropicClient.Tests/Unit/Models/CreateFileRequestTests.cs b/tests/AnthropicClient.Tests/Unit/Models/CreateFileRequestTests.cs
index e69de29..0b749dd 100644
--- a/tests/AnthropicClient.Tests/Unit/Models/CreateFileRequestTests.cs
+++ b/tests/AnthropicClient.Tests/Unit/Models/CreateFileRequestTests.cs
@@ -0,0 +1,106 @@
+namespace AnthropicClient.Tests.Unit.Models;
+
+public class CreateFileRequestTests
+{
+  [Fact]
+  public void Constructor_WhenCalledWithBytes_ItShouldInitializeProperties()
+  {
+    var fileContent = new byte[] { 1, 2, 3 };
+    var fileName = "test.txt";
+    var fileType = "text/plain";
+
+    var request = new CreateFileRequest(fileContent, fileName, fileType);
+
+    request.File.Should().BeSameAs(fileContent);
+    request.FileName.Should().Be(fileName);
+    request.FileType.Should().Be(fileType);
+  }
+
+  [Fact]
+  public void Constructor_WhenCalledWithStream_ItShouldInitializeProperties()
+  {
+    using var stream = new MemoryStream([1, 2, 3]);
+    var fileName = "test.txt";
+    var fileType = "text/plain";
+
+    var request = new CreateFileRequest(stream, fileName, fileType);
+
+    request.File.Should().BeEquivalentTo(new byte[] { 1, 2, 3 });
+    request.FileName.Should().Be(fileName);
+    request.FileType.Should().Be(fileType);
+  }
+
+  [Fact]
+  public void Constructor_WhenCalledWithNullBytes_ItShouldThrowArgumentNullException()
+  {
+    var act = () => new CreateFileRequest((byte[])null!, "test.txt", "text/plain");
+    act.Should().Throw<ArgumentNullException>();
+  }
+
+  [Fact]
+  public void Constructor_WhenCalledWithBytesAndNullFileName_ItShouldThrowArgumentException()
+  {
+    var act = () => new CreateFileRequest([1, 2, 3], null!, "text/plain");
+    act.Should().Throw<ArgumentException>();
+  }
+
+  [Fact]
+  public void Constructor_WhenCalledWithBytesAndFileNameIsEmpty_ItShouldThrowArgumentException()
+  {
+    var act = () => new CreateFileRequest([1, 2, 3], string.Empty, "text/plain");
+    act.Should().Throw<ArgumentException>();
+  }
+
+  [Fact]
+  public void Constructor_WhenCalledWithBytesAndNullFileType_ItShouldThrowArgumentException()
+  {
+    var act = () => new CreateFileRequest([1, 2, 3], "test.txt", null!);
+    act.Should().Throw<ArgumentException>();
+  }
+
+  [Fact]
+  public void Constructor_WhenCalledWithBytesAndFileTypeIsEmpty_ItShouldThrowArgumentException()
+  {
+    var act = () => new CreateFileRequest([1, 2, 3], "test.txt", string.Empty);
+    act.Should().Throw<ArgumentException>();
+  }
+
+  [Fact]
+  public void Constructor_WhenCalledWithNullStream_ItShouldThrowArgumentNullException()
+  {
+    var act = () => new CreateFileRequest((Stream)null!, "test.txt", "text/plain");
+    act.Should().Throw<ArgumentNullException>();
+  }
+
+  [Fact]
+  public void Constructor_WhenCalledWithStreamAndNullFileName_ItShouldThrowArgumentException()
+  {
+    using var stream = new MemoryStream([1, 2, 3]);
+    var act = () => new CreateFileRequest(stream, null!, "text/plain");
+    act.Should().Throw<ArgumentException>();
+  }
+
+  [Fact]
+  public void Constructor_WhenCalledWithStreamAndFileNameIsEmpty_ItShouldThrowArgumentException()
+  {
+    using var stream = new MemoryStream([1, 2, 3]);
+    var act = () => new CreateFileRequest(stream, string.Empty, "text/plain");
+    act.Should().Throw<ArgumentException>();
+  }
+
+  [Fact]
+  public void Constructor_WhenCalledWithStreamAndNullFileType_ItShouldThrowArgumentException()
+  {
+    using var stream = new MemoryStream([1, 2, 3]);
+    var act = () => new CreateFileRequest(stream, "test.txt", null!);
+    act.Should().Throw<ArgumentException>();
+  }
+
+  [Fact]
+  public void Constructor_WhenCalledWithStreamAndFileTypeIsEmpty_ItShouldThrowArgumentException()
+  {
+    using var stream = new MemoryStream([1, 2, 3]);
+    var act = () => new CreateFileRequest(stream, "test.txt", string.Empty);
+    act.Should().Throw<ArgumentException>();
+  }
+}
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