Add documentation for test artifacts/attachments

docs/docs/migration/mstest.md

@@ -300,6 +300,39 @@ public class MyTests
 }
 ```
 
+### Test Attachments
+
+```csharp
+// MSTest
+[TestMethod]
+public void TestWithAttachment()
+{
+    // Test logic
+    var logPath = "test-log.txt";
+    File.WriteAllText(logPath, "test logs");
+
+    TestContext.AddResultFile(logPath);
+}
+
+// TUnit
+[Test]
+public async Task TestWithAttachment()
+{
+    // Test logic
+    var logPath = "test-log.txt";
+    await File.WriteAllTextAsync(logPath, "test logs");
+
+    TestContext.Current!.Output.AttachArtifact(new Artifact
+    {
+        File = new FileInfo(logPath),
+        DisplayName = "Test Log",
+        Description = "Logs captured during test execution"  // Optional
+    });
+}
+```
+
+For more information about working with test artifacts, including session-level artifacts and best practices, see the [Test Artifacts guide](../test-lifecycle/artifacts.md).
+
 ### Assert.Fail
 
 ```csharp

docs/docs/migration/nunit.md

@@ -25,6 +25,7 @@ Migrating from NUnit to TUnit can significantly improve test execution speed. Be
 | `Assert.That(actual, Is.EqualTo(expected))` | `await Assert.That(actual).IsEqualTo(expected)` |
 | `Assert.Throws<T>(() => ...)` | `await Assert.ThrowsAsync<T>(() => ...)` |
 | `TestContext.WriteLine(...)` | `TestContext` parameter with `context.OutputWriter.WriteLine(...)` |
+| `TestContext.AddTestAttachment(path, name)` | `TestContext.Current!.Output.AttachArtifact(new Artifact { File = new FileInfo(path), DisplayName = name })` |
 | `CollectionAssert.AreEqual(expected, actual)` | `await Assert.That(actual).IsEquivalentTo(expected)` |
 | `StringAssert.Contains(substring, text)` | `await Assert.That(text).Contains(substring)` |
 
@@ -247,6 +248,39 @@ public async Task MyTest(TestContext context)
 }
 ```
 
+### Test Attachments
+
+```csharp
+// NUnit
+[Test]
+public void TestWithAttachment()
+{
+    // Test logic
+    var logPath = "test-log.txt";
+    File.WriteAllText(logPath, "test logs");
+
+    TestContext.AddTestAttachment(logPath, "Test Log");
+}
+
+// TUnit
+[Test]
+public async Task TestWithAttachment()
+{
+    // Test logic
+    var logPath = "test-log.txt";
+    await File.WriteAllTextAsync(logPath, "test logs");
+
+    TestContext.Current!.Output.AttachArtifact(new Artifact
+    {
+        File = new FileInfo(logPath),
+        DisplayName = "Test Log",
+        Description = "Logs captured during test execution"  // Optional
+    });
+}
+```
+
+For more information about working with test artifacts, including session-level artifacts and best practices, see the [Test Artifacts guide](../test-lifecycle/artifacts.md).
+
 ### Combinatorial Testing
 
 #### Values and Combinatorial → Matrix

docs/docs/migration/xunit.md

@@ -690,6 +690,57 @@ public class LoggingTests
 - Access output via `context.OutputWriter.WriteLine()`
 - TestContext provides additional test metadata
 
+#### Test Attachments
+
+xUnit v3 introduced test attachments. TUnit also supports this capability:
+
+**xUnit v3 Code:**
+```csharp
+public class TestWithAttachments
+{
+    private readonly ITestContextAccessor _testContextAccessor;
+
+    public TestWithAttachments(ITestContextAccessor testContextAccessor)
+    {
+        _testContextAccessor = testContextAccessor;
+    }
+
+    [Fact]
+    public async Task Test_WithAttachment()
+    {
+        // Test logic
+        var logPath = "test-log.txt";
+        await File.WriteAllTextAsync(logPath, "test logs");
+
+        _testContextAccessor.Current!.Attachments.Add(
+            new FileAttachment(logPath, "Test Log"));
+    }
+}
+```
+
+**TUnit Equivalent:**
+```csharp
+public class TestWithAttachments
+{
+    [Test]
+    public async Task Test_WithAttachment()
+    {
+        // Test logic
+        var logPath = "test-log.txt";
+        await File.WriteAllTextAsync(logPath, "test logs");
+
+        TestContext.Current!.Output.AttachArtifact(new Artifact
+        {
+            File = new FileInfo(logPath),
+            DisplayName = "Test Log",
+            Description = "Logs captured during test execution"  // Optional
+        });
+    }
+}
+```
+
+For more information about working with test artifacts, including session-level artifacts and best practices, see the [Test Artifacts guide](../test-lifecycle/artifacts.md).
+
 ### Traits and Categories
 
 #### Trait → Property