Eris\Generator\GeneratedValueTest::testCanBeMappedToDeriveValues PHP Method

    public function testCanBeMappedToDeriveValues()
    {
        $initialValue = GeneratedValue::fromJustValue(3, 'my-generator');
        $this->assertEquals(GeneratedValue::fromValueAndInput(6, $initialValue, 'derived-generator'), $initialValue->map(function ($value) {
            return $value * 2;
        }, 'derived-generator'));
    }