Official test suite ("spectests")

Written in Perl 6, maintained in Pugs repository

Currently ~18,000 tests

Roughly organized by Synopsis chapter and subsection

S04-statements/for.t
S04-statements/given.t
S04-statements/if.t
S04-statements/repeat.t
S04-statements/return.t
S04-statements/try.t
S04-statements/unless.t
S04-statements/until.t
S04-statements/while.t