An R6RS library for xUnit == License New BSD License == Introduction We propose an xUnit test utility (xunit) in which you can assert and investigate if a testee program's behaviour satisfies expected requirements. The way we recommend to specify expected requirements is in terms of predicates, especially equivalence relations, because they are suitable to detect fundamental properties of the dynamic environment of, and by, Scheme programs. (xunit) offers you useful macros which contain * assertions for standard predicates and equivalence relations, * 'define-assert-equivalence', defining a custom assertion on some equivalence relation, and * 'define-assert-predicate', defining a custom assertion on some predicate.