The author of this text is a developer at MongoDB who experimented with conformance checking techniques to ensure that their code matches their formal specifications written in TLA+. Conformance checking involves testing whether the implementation's behaviors conform to the specification. The author attempted two approaches: trace-checking and test-case generation. Trace-checking involved generating execution traces from the implementation and checking if they match the spec, while test-case generation started with a spec and generated tests that force the implementation to follow specific behaviors. The author found that both techniques can be challenging but also worthwhile, especially when done correctly. In the past five years, there has been progress in conformance checking techniques, including new tools and approaches for language-specific testing. The author is excited about growing interest in conformance checking and hopes it will lead to standard tools that help engineers keep their code and specs in sync.