public function testFromPredicate_WithUnmatched_ReturnsNone()
{
$expect = 13;
$f = function ($input) {
return false;
};
$ifSome = function ($input) {
$this->fail();
};
$ifNone = function () use($expect) {
return $expect;
};
$actual = Option::fromPredicate($f, $expect)->match($ifSome, $ifNone);
$this->assertEquals($expect, $actual);
}
public function map(callable $f)
{
return $this->has_value ? Option::some($f($this->value)) : Option::none();
}