# operator - -
{
  my $na = Rstats::Util::NA;
  my $ret = $na - 1;
  is(ref $ret, 'Rstats::Element::NA');
}

# operator - *
{
  my $na = Rstats::Util::NA;
  my $ret = $na * 1;
  is(ref $ret, 'Rstats::Element::NA');
}

# operator - /
{
  my $na = Rstats::Util::NA;
  my $ret = $na / 1;
  is(ref $ret, 'Rstats::Element::NA');
}

# operator - **
{
  my $na = Rstats::Util::NA;
  my $ret = $na ** 1;
  is(ref $ret, 'Rstats::Element::NA');
}

# operator - %
{
  my $na = Rstats::Util::NA;
  my $ret = $na % 1;
  is(ref $ret, 'Rstats::Element::NA');
}

# operator - negation
{
  my $na = Rstats::Util::NA;
  my $ret = -$na;
  is(ref $ret, 'Rstats::Element::NA');
}

# operator - <
{
  my $na = Rstats::Util::NA;
  my $ret = $na < 1;
  is(ref $ret, 'Rstats::Element::NA');
}

# operator - <=
{
  my $na = Rstats::Util::NA;
  my $ret = $na <= 1;
  is(ref $ret, 'Rstats::Element::NA');
}

# operator - >
{
  my $na = Rstats::Util::NA;
  my $ret = $na > 1;
  is(ref $ret, 'Rstats::Element::NA');
}

# operator - >=
{
  my $na = Rstats::Util::NA;
  my $ret = $na >= 1;
  is(ref $ret, 'Rstats::Element::NA');
}

# operator - ==
{
  my $na = Rstats::Util::NA;
  my $ret = $na == 1;
  is(ref $ret, 'Rstats::Element::NA');
}

# operator - !=
{
  my $na = Rstats::Util::NA;
  my $ret = $na != 1;
  is(ref $ret, 'Rstats::Element::NA');
}
}

# numeric operator { # numeric operator - + { my $nan = Rstats::Util::NaN; my $ret = $nan + 1; is(ref $ret, 'Rstats::NaN'); }

# numeric operator - -
{
  my $nan = Rstats::Util::NaN;
  my $ret = $nan - 1;
  is(ref $ret, 'Rstats::NaN');
}

# numeric operator - *
{
  my $nan = Rstats::Util::NaN;
  my $ret = $nan * 1;
  is(ref $ret, 'Rstats::NaN');
}

# numeric operator - /
{
  my $nan = Rstats::Util::NaN;
  my $ret = $nan / 1;
  is(ref $ret, 'Rstats::NaN');
}

# numeric operator - **
{
  my $nan = Rstats::Util::NaN;
  my $ret = $nan ** 1;
  is(ref $ret, 'Rstats::NaN');
}

# numeric operator - %
{
  my $nan = Rstats::Util::NaN;
  my $ret = $nan % 1;
  is(ref $ret, 'Rstats::NaN');
}

# numeric operator - negation
{
  my $nan = Rstats::Util::NaN;
  my $ret = -$nan;
  is(ref $ret, 'Rstats::NaN');
}
}

# comparison operator { # comparison operator - <, number { my $nan = Rstats::Util::NaN; my $ret = $nan < 1; is(ref $ret, 'Rstats::Element::NA'); }

# comparison operator - <, complex
{
  my $nan = Rstats::Util::NaN;
  my $ret = $nan < $r->complex(1,1);
  is(ref $ret, 'Rstats::Element::NA');
}

# comparison operator - ==, character
{
  my $nan = Rstats::Util::NaN;
  my $ret = $nan == 'a';
  is($ret, $r->FALSE);
}

# comparison operator - ==, character
{
  my $nan = Rstats::Util::NaN;
  my $ret = $nan == 'NaN';
  is($ret, $r->TRUE);
}

# comparison operator - <=
{
  my $nan = Rstats::Util::NaN;
  my $ret = $nan <= 1;
  is(ref $ret, 'Rstats::Element::NA');
}

# comparison operator - >
{
  my $nan = Rstats::Util::NaN;
  my $ret = $nan > 1;
  is(ref $ret, 'Rstats::Element::NA');
}

# comparison operator - >=
{
  my $nan = Rstats::Util::NaN;
  my $ret = $nan >= 1;
  is(ref $ret, 'Rstats::Element::NA');
}

# comparison operator - ==
{
  my $nan = Rstats::Util::NaN;
  my $ret = $nan == 1;
  is(ref $ret, 'Rstats::Element::NA');
}

# comparison operator - !=
{
  my $nan = Rstats::Util::NaN;
  my $ret = $nan != 1;
  is(ref $ret, 'Rstats::Element::NA');
}
}