class TestCase::Operator::Concat {
  static method concat_empty_string : int () {
    {
      my $text = "abc" . "";
      unless ($text eq "abc") {
        return 0;
      }
    }
    {
      my $text = "" . "abc";
      unless ($text eq "abc") {
        return 0;
      }
    }
    {
      my $text = "" . "";
      unless ($text eq "") {
        return 0;
      }
    }
    {
      my $text = "";
      $text .= "";
      unless ($text eq "") {
        return 0;
      }
    }
    {
      my $text = "";
      $text . "";
    }
    return 1;
  }
   
  static method concat_string : int () {
     
    {
      my $string = "abc" . "def";
      unless ($string isa string) {
        return 0;
      }
      unless ($string eq "abcdef") {
        return 0;
      }
    }
    {
      my $string = "abc" . (byte[])"def";
      unless ($string isa string) {
        return 0;
      }
      unless ($string eq "abcdef") {
        return 0;
      }
    }
    {
      my $string = (byte[])"abc" . "def";
      unless ($string isa string) {
        return 0;
      }
      unless ($string eq "abcdef") {
        return 0;
      }
    }
     
    return 1;
  }
  static method concat_left_is_number : int () {
     
    my $string = 13 . "abc";
     
    unless ($string eq "13abc") {
      return 0;
    }
     
    return 1;
  }
  static method concat_right_is_number : int () {
     
    my $string = "abc" . 0.25;
     
    unless ($string eq "abc0.25") {
      return 0;
    }
     
    return 1;
  }
  static method concat_left_is_undef : int () {
     
    eval {
      my $string : string = undef;
      $string . "abc";
    };
     
    unless ($@) {
      return 0;
    }
    $@ = undef;
     
    return 1;
  }
  static method concat_right_is_undef : int () {
     
    eval {
      my $string : string = undef;
      "abc" . $string;
    };
     
    unless ($@) {
      return 0;
    }
    $@ = undef;
     
    return 1;
  }
}