phpstreams\tests\unit\CollectorsTest::testReducing PHP Method

    public function testReducing()
    {
        $instance = Collectors::reducing(1, function ($a, $b) {
            return $a * $b;
        });
        $instance->add("foo", 2);
        $instance->add("bar", 3);
        $instance->add("baz", 4);
        $this->assertEquals(24, $instance->get());
    }