Ensure arg is valid

assert  arg (anything)

Raises an exception if the argument is either nil or false.

Introduced in v2.8

Examples

# Example 1


assert true  
assert 1     
assert "foo"
assert false

# Simple assertions
# As true is neither nil or false, this assertion passes
# Similarly, 1 passes
# As do string
# This will raise an exception

# Example 2


assert false, "oops"

# Communicating error messages
# This will raise an exception containing the message "oops"

# Example 3


assert (1 + 1) == 2
assert [:a, :b, :c].size == 3

# More interesting assertions
# Ensure that arithmetic is sane!
# ensure lists can be correctly counted