sub test_ordered {
  my ( $ref, $test ) = @_;

  # $i scans the indices of @$ref;
  # $matched keeps count of # of elements matched in @$test;
  my ( $i, $matched ) = ( 0, 0 );
OUTER: for ( @$test ) {
    while ( $i < @$ref or return 0 ) {
      if ( $ref->[ $i++ ] eq $_ ) {
        last OUTER if ++$matched == @$test;
        last;
      }
    }
  }
  return 1;
}
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