class TestCase::Module::EqualityChecker {
  use Fn;
  use EqualityChecker;
  use StringBuffer;
   
  static method default_equality_checker : int () {
     
    {
      my $buffer1 = StringBuffer->new("a");
       
      my $buffer2 = StringBuffer->new("b");
       
      my $buffer3 = StringBuffer->new("b");
       
      my $default_equality_checker = EqualityChecker->default_equality_checker;
       
      unless ($default_equality_checker->($buffer1, $buffer2) == 0) {
        return 0;
      }
       
      unless ($default_equality_checker->($buffer2, $buffer3) == 1) {
        return 0;
      }
       
      unless ($default_equality_checker->($buffer1, undef) == 0) {
        return 0;
      }
       
      unless ($default_equality_checker->(undef, $buffer2) == 0) {
        return 0;
      }
       
      unless ($default_equality_checker->(undef, undef) == 1) {
        return 0;
      }
       
    }
     
    return 1;
  }
}