"Should throw IllegalArgumentException for null message");
    }

    @Test
    @DisplayName("Should successfully encrypt and decrypt with refactored methods")
    void testRefactoredEncryptionDecryption() throws Exception {
        // Given - Use same key for both encryption and decryption in test

* `refactor`: Refactors
    * This is normally for changes to the internal code that don't change the behavior. Normally it improves maintainability, or enables future features, etc.
* `upgrade`: Upgrades

<div class="screenshot">
<img src="/img/tutorial/sql-databases/image01.png">
</div>

## Update the App with Multiple Models { #update-the-app-with-multiple-models }

Now let's **refactor** this app a bit to increase **security** and **versatility**.

If you check the previous app, in the UI you can see that, up to now, it lets the client decide the `id` of the `Hero` to create. 😱

   * href="http://mathworld.wolfram.com/PrimeNumber.html">prime number</a>: an integer <i>greater
   * than one</i> that cannot be factored into a product of <i>smaller</i> positive integers.
   * Returns {@code false} if {@code n} is zero, one, or a composite number (one which <i>can</i> be
   * factored into smaller positive integers).
   *
   * <p>To test larger numbers, use {@link BigInteger#isProbablePrime}.
   *

/// tip

Het feit dat dit **standaard Python** is, betekent dat je nog steeds de **best mogelijke ontwikkelaarservaring** krijgt in je editor, met de hulpmiddelen die je gebruikt om je code te analyseren en te refactoren, enz. ✨

Daarnaast betekent het ook dat je code zeer verenigbaar zal zijn met veel andere Python-hulpmiddelen en -pakketten. 🚀

///

## Type hints in **FastAPI**

 */
// TODO: Descriptive assertion messages, with hints as to probable fixes.
// TODO: Add another constructor parameter indicating whether the class under test is ordered, and
// check the order if so.
// TODO: Refactor to share code with SetTestBuilder etc.
@GwtCompatible
@NullMarked
public abstract class MapInterfaceTest<K extends @Nullable Object, V extends @Nullable Object>
    extends TestCase {

Later you will see how **powerful** it can be.

/// tip

The fact that this is **standard Python** means that you will still get the **best possible developer experience** in your editor, with the tools you use to analyze and refactor your code, etc. ✨

And also that your code will be very compatible with many other Python tools and libraries. 🚀

///

## Type hints in **FastAPI** { #type-hints-in-fastapi }