Tests if test is true. msg may be a String or a Proc. If msg is a String, it will be used as the failure message. Otherwise, the result of calling msg will be used as the message if the assertion fails. If no msg is given, a default message will be used. assert(false, "This was expected to be true") # File test/unit/assertions.rb, line 29 def assert(test, msg = UNASSIGNED) case msg when UNASSIGNED