Test of what's a string in Puppet.

string_test.pp

$tests = [
    "hello",
    undef,
    44,
    "{3 => 4}",
    "world!"
    ]

string_test { $tests: }

define string_test ($test = $title) {
  if is_string($test) {
    notify{"yes, ${test} is a string.\n":}
  } else {
    notify {"no, ${test} is NOT a string.\n":}
  }
}