Record a failure at the current scope

Log a message

Label a test. Can be nested. A "." is placed between nested scopes, so scope "foo" . scope "bar" is equivalent to scope "foo.bar"

Status of a test

Tests are values of type Test a, and Test forms a monad with access to:

• repeatable randomness (the random and random' functions for random and bounded random values, or handy specialized int, int', double, double', etc)
• I/O (via liftIO or io, which is an alias for liftIO)
• failure (via crash, which yields a stack trace, or fail, which does not)
• logging (via note, noteScoped, or note')
• hierarchically-named subcomputations (under scope) which can be switched on and off via runOnly
• parallelism (via fork)
• conjunction of tests via MonadPlus (the <|> operation runs both tests, even if the first test fails, and the tests function used above is just msum).

Using any or all of these capabilities, you assemble Test values into a "test suite" (just another Test value) using ordinary Haskell code, not framework magic. Notice that to generate a list of random values, we just replicateM and forM as usual.