serde_test 1.0.177 is a test helper for the serde crate: assert_tokens/assert_ser_tokens/assert_de_tokens over a Token enum mirroring serde's data model. Pure safe Rust, no unsafe, no FFI, no I/O, no concurrency, one runtime dependency (serde). Source matches upstream byte-for-byte modulo cargo's normal Cargo.toml normalisation. One low-severity finding: no in-tree #[test] items — coverage is via doctests and the separate serde test suite.