As generative AI (GenAI) applications become central to modern software stacks, ensuring their reliability through robust unit testing is more important than ever. Amazon Bedrock, AWS's managed service for foundation models (FMs) from providers like Anthropic, AI21, Cohere, Meta, and Stability AI, allows developers to build scalable GenAI applications without managing infrastructure. However, testing these applications presents unique challenges — such as handling non-deterministic outputs and API dependencies.