fn test_error_can_be_converted_to_string() {
	assert 'an error' == error('an error').str()
}

fn test_error_can_be_assigned_to_a_variable() {
	f := error('an error')
	assert 'an error' == f.msg()
}

fn test_error_can_be_printed() {
	f := error('an error')
	println(f)
	assert true
}

fn test_error_can_be_interpolated_in_a_string() {
	f := error('an error')
	s := 'hi ${f}'
	assert s == 'hi an error'
}