Base JUnit 5 class for UI unit tests. The class automatically scans classpath for routes and error views. Subclasses should typically restrict classpath scanning to a specific packages for faster bootstrap, by using ViewPackages annotation. If the annotation is not present a full classpath scan is performed

@ViewPackages(classes = {CartView.class, CheckoutView.class})
class CartViewTest extends UIUnitTest {
}

@ViewPackages(packages = {"com.example.shop.cart", "com.example.security"})
class CartViewTest extends UIUnitTest {
}

@ViewPackages(
   classes = {CartView.class, CheckoutView.class},
   packages = {"com.example.security"}
)
class CartViewTest extends UIUnitTest {
}
</pre>

Set up of Vaadin environment is performed before each test by {
#initVaadinEnvironment()} method, and will be executed before
{@BeforeEach} methods defined in subclasses. At the same way, cleanup
tasks operated by {#cleanVaadinEnvironment()} are executed after each
test, and after all {@AfterEach} annotated methods in subclasses.

Usually, it is not necessary to override {#initVaadinEnvironment()} or
{#cleanVaadinEnvironment()} methods, but if this is done it is
mandatory to add the {@BeforeEach} and {@AfterEach} annotations
in the subclass, in order to have hooks handled by testing framework.

A use case for overriding {#initVaadinEnvironment()} is to provide
custom Flow service implementations supported by {
com.vaadin.flow.di.Lookup} SPI. Implementations can be provided overriding
{#initVaadinEnvironment()} and passing to super implementation the
service classes that should be initialized during setup.

<pre>
{
&#64;BeforeEach
&#64;Override
void initVaadinEnvironment() {
    super.initVaadinEnvironment(CustomInstantiatorFactory.class);
}
}
</pre>
<p/>
To get a graphical ascii representation of the UI tree on failure add the
annotation {@ExtendWith(TreeOnFailureExtension.class)} to the test
class.

ViewPackages