public function testBimap()
{
$addOne = function ($x) {
return $x + 1;
};
$takeOne = function ($x) {
return $x - 1;
};
$id = function ($x) {
return $x;
};
$a = new Right(2);
$b = new Left(2);
$this->assertEquals($a->bimap($addOne, $takeOne)->either($id, $id), 1, 'Bimaps a Right.');
$this->assertEquals($b->bimap($addOne, $takeOne)->either($id, $id), 3, 'Bimaps a Left.');
}