Plain meaning
Start with the shortest useful explanation before going deeper.
The process of validating Solana programs through unit tests, integration tests, and fuzz testing. Common approaches: Rust tests with solana-program-test or LiteSVM (fast, in-process), TypeScript tests with Bankrun or solana-test-validator (end-to-end), and fuzz testing with Trident. Best practice is testing both happy paths and attack vectors (missing signers, wrong owners).