`exception Test_fail of string * string list`

Exception raised when a test failed, with the list of counter-examples. `Test_fail (name, l)` means test `name` failed on elements of `l`.

`exception Test_error of string * string * exn * string`

Exception raised when a test raised an exception `e`, with the sample that triggered the exception. `Test_error (name, i, e, st)` means `name` failed on `i` with exception `e`, and `st` is the stacktrace (if enabled) or an empty string.

`exception Test_unexpected_success of string`

Exception raised when a negative test failed. `Test_unexpected_success name` means test `name` failed to find an expected counter example.