The type for test outputs. Ellipisis (...) allow to skip zero, one or many lines while comparing the outputs with equal.

equal x y is true iff x and y are equivalent, modulo ellipsis.

merge output test merges any `Ellipsis items from test into output.

pp is the pretty-printer for test outputs. pad is the size of the optional whitespace left-padding (by default it is 0).

dump is the printer for dumping test outputs. Useful for debugging.