Assert

require 'binding_of_caller'

def assert(cond)
  puts 'row [%s] / FAIL! [%s]' % [caller[-1].split(':')[1], cond] \
    unless eval(cond, binding.of_caller(1))
end

namn = 'holger'
assert %(namn == 'hulken') # => row [9] / FAIL! [namn == 'hulken']
assert %(namn == 'holger') # =>