Wraps Amazon.Lambda.TestTool (the canonical .NET Lambda local-testing toolkit from github.com/aws/aws-lambda-dotnet) for invoking Lambda handlers from xUnit / NUnit tests with simulated AWS Lambda contexts (ILambdaContext, ILambdaSerializer). Covers handler-direct invocation, mock context fixtures, the dotnet-lambda CLI, and integration with the .NET LambdaSerializer for JSON. Use when testing AWS Lambda functions written in C#/.NET.