public function testIngredientWhenValid()
{
$item = 'butter';
$amount = 1;
$unit = 'slices';
$usedBy = new DateTime('+30 day');
$ingredient = new Ingredient($item, $amount, $unit, $usedBy);
$this->assertEquals($ingredient->getItem(), $item);
$this->assertEquals($ingredient->getAmount(), $amount);
$this->assertEquals($ingredient->getUnit(), $unit);
$this->assertEquals($ingredient->getUsedBy(), $usedBy);
$this->assertEquals($ingredient->hasExpired(), false);
}