Testing

1. Testing

If you are going to use Apache Isis for developing complex business-critical applications, then being able to write automated tests for those applications becomes massively important. As such Apache Isis treats the topic of testing very seriously. (Though we say it ourselves), the framework has support that goes way above what is provided by other application frameworks.

This guide describes those features available to you for testing your Apache Isis application.

Apache Isis documentation is broken out into a number of user, reference and "supporting procedures" guides.

The user guides available are:

The reference guides are:

The remaining guides are:

  • Developers' Guide (how to set up a development environment for Apache Isis and contribute back to the project)

  • Committers' Guide (release procedures and related practices)

2. Overview

2.1. Unit tests vs Integ tests

We divide automated tests into two broad categories:

  • unit tests exercise a single unit (usually a method) of a domain object, in isolation.

    Dependencies of that object are mocked out. These are written by a developer and for a developer; they are to ensure that a particular "cog in the machine" works correctly

  • integration tests exercise the application as a whole, usually focusing on one particular business operation (action).

    These are tests that represent the acceptance criteria of some business story; their intent should make sense to the domain expert (even if the domain expert is "non-technical")

To put it another way:

Integration tests help ensure that you are building the right system

Unit tests help ensure that you are building the system right.

2.2. Integ tests vs BDD Specs

We further sub-divide integration tests into:

  • those that are implemented in Java and JUnit (we call these simply "integration tests")

    Even if a domain expert understands the intent of these tests, the actual implementation will be opaque to them. Also, the only output from the tests is a (hopefully) green CI job

  • tests (or rather, specifications) that are implemented in a behaviour-driven design (BDD) language such as Cucumber (we call these "BDD specs")

    The natural language specification then maps down onto some glue code that is used to drive the application. But the benefits of taking a BDD approach include the fact that your domain expert will be able to read the tests/specifications, and that when you run the specs, you also get documentation of the application’s behaviour ("living documentation").

It’s up to you whether you use BDD specs for your apps; it will depend on your development process and company culture. But you if don’t then you certainly should write integration tests: acceptance criteria for user stories should be automated!

2.3. Simulated UI (WrapperFactory)

When we talk about integration tests/specs here, we mean tests that exercise the domain object logic, through to the actual database. But we also want the tests to exercise the app from the users’s perspective, which means including the user interface.

For most other frameworks that would require having to test the application in a very heavy weight/fragile fashion using a tool such as Selenium, driving a web browser to navigate . In this regard though, Apache Isis has a significant trick up its sleeve. Because Apache Isis implements the naked objects pattern, it means that the UI is generated automatically from the UI. This therefore allows for other implementations of the UI.

The WrapperFactory domain service allows a test to wrap domain objects and thus to interact with said objects "as if" through the UI:

integ tests

If the test invokes an action that is disabled, then the wrapper will throw an appropriate exception. If the action is ok to invoke, it delegates through.

What this means is that an Isis application can be tested end-to-end without having to deploy it onto a webserver; the whole app can be tested while running in-memory. Although integration tests re (necessarily) slower than unit tests, they are not any harder to write (in fact, in some respects they are easier).

2.4. Dependency Injection

Isis provides autowiring dependency injection into every domain object. This is most useful when writing unit tests; simply mock out the service and inject into the domain object.

There are a number of syntaxes supported, but the simplest is to use @javax.inject.Inject annotation; for example:

@javax.inject.Inject
CustomerRepository customers;

Isis can inject into this even if the field has package-level (or even private) visibility. We recommend that you use package-level visibility, though, so that your unit tests (in the same package as the class under test) are able to inject mocks.

Isis does also support a couple of other syntaxes:

public void setCustomerRepository(CustomerRepository customers) { ... }

or

public void injectCustomerRepository(CustomerRepository customers) { ... }

Apache Isis also supports automatic dependency injection into integration tests; just declare the service dependency in the usual fashion and it will be automatically injected.

2.5. Given/When/Then

Whatever type of test/spec you are writing, we recommend you follow the given/when/then idiom:

  • given the system is in this state (preconditions)

  • when I poke it with a stick

  • then it looks like this (postconditions)

A good test should be 5 to 10 lines long; the test should be there to help you reason about the behaviour of the system. Certainly if the test becomes more than 20 lines it’ll be too difficult to understand.

The "when" part is usually a one-liner, and in the "then" part there will often be only two or three assertions that you want to make that the system has changed as it should.

For unit test the "given" part shouldn’t be too difficult either: just instantiate the class under test, wire in the appropriate mocks and set up the expectations. And if there are too many mock expectations to set up, then "listen to the tests" …​ they are telling you your design needs some work.

Where things get difficult though is the "given" for integration tests; which is the topic of the next section…​

2.6. Fixture Management

In the previous section we discussed using given/when/then as a form of organizing tests, and why you should keep your tests small.

For integration tests though it can be difficult to keep the "given" short; there could be a lot of prerequisite data that needs to exist before you can actually exercise your system. Moreover, however we do set up that data, but we also want to do so in a way that is resilient to the system changing over time.

The solution that Apache Isis provides is a domain service called Fixture Scripts, that defines a pattern and supporting classes to help ensure that the "data setup" for your tests are reusable and maintainable over time.

2.7. Fake data

In any given test there are often quite a few variables involved, to initialize the state of the objects, or to act as arguments for invoking a method, or when asserting on post-conditions. Sometimes those values are important (eg verifying that an `Order’s state went from PENDING to SHIPPED, say), but often they aren’t (a customer’s name, for example) but nevertheless need to be set up (especially in integration tests).

We want our tests to be easily understood, and we want the reader’s eye to be drawn to the values that are significant and ignore those that are not.

One way to do this is to use random (or fake) values for any insignificant data. This in effect tells the reader that "any value will do". Moreover, if it turns out that any data won’t do, and that there’s some behaviour that is sensitive to the value, then the test will start to flicker, passing and then failing depending on inputs. This is A Good Thing™.

Apache Isis does not, itself, ship with a fake data library. However, the (non-ASF) Incode Platform's fakedata module (non-ASF) does provide exactly this capability.

Using fake data works very well with fixture scripts; the fixture script can invoke the business action with sensible (fake/random) defaults, and only require that the essential information is passed into it by the test.

2.8. Feature Toggles

Writing automated tests is just good development practice. Also good practice is developing on the mainline (master, trunk); so that your continuous integration system really is integrating all code. Said another way: don’t use branches!

Sometimes, though, a feature will take longer to implement than your iteration cycle. In such a case, how do you use continuous integration to keep everyone working on the mainline without revealing a half-implemented feature on your releases? One option is to use feature toggles.

Apache Isis does not, itself, ship with a feature toggle library. However, the (non-ASF) Incode Platform's togglz module does provide exactly this capability.

With all that said, let’s look in detail at the testing features provided by Apache Isis.

3. Unit Test Support

Isis Core provides a number of unit test helpers for you to use (if you wish) to unit test your domain objects.

3.1. Contract Tests

Contract tests ensure that all instances of a particular idiom/pattern that occur within your codebase are implemented correctly. You could think of them as being a way to enforce a certain type of coding standard. Implementation-wise they use Reflections library to scan for classes.

3.1.1. SortedSets

This contract test automatically checks that all fields of type java.util.Collection are declared as java.util.SortedSet. In other words, it precludes either java.util.List or java.util.Set from being used as a collection.

For example, the following passes the contract test:

public class Department {
    private SortedSet<Employee> employees = new TreeSet<Employee>();
    ...
}

whereas this would not:

public class SomeDomainObject {
    private List<Employee> employees = new ArrayList<Employee>();
    ...
}

If using DataNucleus against an RDBMS (as you probably are) then we strongly recommend that you implement this test, for several reasons:

  • first, Sets align more closely to the relational model than do Lists. A List must have an additional index to specify order.

  • second, SortedSet is preferable to Set because then the order is well-defined and predictable (to an end user, to the programmer).

    The ObjectContracts utility class substantially simplifies the task of implementing Comparable in your domain classes.

  • third, if the relationship is bidirectional then JDO/Objectstore will automatically maintain the relationship.

To use the contract test, subclass SortedSetsContractTestAbstract, specifying the root package to search for domain classes.

For example:

public class SortedSetsContractTestAll extends SortedSetsContractTestAbstract {

    public SortedSetsContractTestAll() {
        super("org.estatio.dom");
        withLoggingTo(System.out);
    }
}

3.1.2. Bidirectional

This contract test automatically checks that bidirectional 1:m or 1:1 associations are being maintained correctly (assuming that they follow the mutual registration pattern

(If using the JDO objectstore, then) there is generally no need to programmatically maintain 1:m relationships (indeed it may introduce subtle errors). For more details, see here. Also check out the templates in the developers' guide (live templates for IntelliJ / editor templates for Eclipse) for further guidance.

For example, suppose that ParentDomainObject and ChildDomainObject have a 1:m relationship (ParentDomainObject#children / ChildDomainObject#parent), and also PeerDomainObject has a 1:1 relationship with itself (PeerDomainObject#next / PeerDomainObject#previous).

The following will exercise these relationships:

public class BidirectionalRelationshipContractTestAll
        extends BidirectionalRelationshipContractTestAbstract {

    public BidirectionalRelationshipContractTestAll() {
        super("org.apache.isis.core.unittestsupport.bidir",
                ImmutableMap.<Class<?>,Instantiator>of(
                    ChildDomainObject.class, new InstantiatorForChildDomainObject(),
                    PeerDomainObject.class, new InstantiatorSimple(PeerDomainObjectForTesting.class)
                ));
        withLoggingTo(System.out);
    }
}

The first argument to the constructor scopes the search for domain objects; usually this would be something like "com.mycompany.dom".

The second argument provides a map of Instantiator for certain of the domain object types. This has two main purposes. First, for abstract classes, it nominates an alternative concrete class to be instantiated. Second, for classes (such as ChildDomainObject) that are Comparable and are held in a SortedSet), it provides the ability to ensure that different instances are unique when compared against each other. If no Instantiator is provided, then the contract test simply attempts to instantiates the class.

If any of the supporting methods (addToXxx(), removeFromXxx(), modifyXxx() or clearXxx()) are missing, the relationship is skipped.

To see what’s going on (and to identify any skipped relationships), use the withLoggingTo() method call. If any assertion fails then the error should be descriptive enough to figure out the problem (without enabling logging).

The example tests can be found here.

3.1.3. Injected Services Method

It is quite common for some basic services to be injected in a project-specific domain object superclass; for example a ClockService might generally be injected everywhere:

public abstract class EstatioDomainObject {
    @javax.inject.Inject
    protected ClockService clockService;
}

If a subclass inadvertantly overrides this method and provides its own ClockService field, then the field in the superclass will never initialized. As you might imagine, NullPointerExceptions could then arise.

This contract test automatically checks that the injectXxx(…​) method, to allow for injected services, is not overridable, ie final.

This contract test is semi-obsolete; most of the time you will want to use @javax.inject.Inject on fields rather than the injectXxx() method. The feature dates from a time before Apache Isis supported the @Inject annotation.

To use the contract test, , subclass SortedSetsContractTestAbstract, specifying the root package to search for domain classes.

For example:

public class InjectServiceMethodMustBeFinalContractTestAll extends InjectServiceMethodMustBeFinalContractTestAbstract {

    public InjectServiceMethodMustBeFinalContractTestAll() {
        super("org.estatio.dom");
        withLoggingTo(System.out);
    }
}

3.1.4. Value Objects

The ValueTypeContractTestAbstract automatically tests that a custom value type implements equals() and hashCode() correctly.

For example, testing JDK’s own java.math.BigInteger can be done as follows:

public class ValueTypeContractTestAbstract_BigIntegerTest extends ValueTypeContractTestAbstract<BigInteger> {

    @Override
    protected List<BigInteger> getObjectsWithSameValue() {
        return Arrays.asList(new BigInteger("1"), new BigInteger("1"));
    }

    @Override
    protected List<BigInteger> getObjectsWithDifferentValue() {
        return Arrays.asList(new BigInteger("2"));
    }
}

The example unit tests can be found here.

3.2. JMock Extensions

As noted earlier, for unit tests we tend to use JMock as our mocking library. The usual given/when/then format gets an extra step:

  • given the system is in this state

  • expecting these interactions (set up the mock expectations here)

  • when I poke it with a stick

  • then these state changes and interactions with Mocks should have occurred.

If using JMock then the interactions (in the "then") are checked automatically by a JUnit rule. However, you probably will still have some state changes to assert upon.

Distinguish between queries vs mutators

For mock interactions that simply retrieve some data, your test should not need to verify that it occurred. If the system were to be refactored and starts caching some data, you don’t really want your tests to start breaking because they are no longer performing a query that once they did. If using JMock API this means using the allowing(..) method to set up the expectation.

On the other hand mocks that mutate the state of the system you probably should assert have occurred. If using JMock this typically means using the oneOf(…​) method.

For more tips on using JMock and mocking in general, check out the GOOS book, written by JMock’s authors, Steve Freeman and Nat Pryce and also Nat’s blog.

Apache Isis' unit test support provides JUnitRuleMockery2 which is an extension to the JMock's JunitRuleMockery. It provides a simpler API and also providing support for autowiring.

For example, here we see that the class under test, an instance of CollaboratingUsingSetterInjection, is automatically wired up with its Collaborator:

public class JUnitRuleMockery2Test_autoWiring_setterInjection_happyCase {

    @Rule
    public JUnitRuleMockery2 context = JUnitRuleMockery2.createFor(Mode.INTERFACES_AND_CLASSES);

    @Mock
    private Collaborator collaborator;

    @ClassUnderTest
    private CollaboratingUsingSetterInjection collaborating;

    @Test
    public void wiring() {
        assertThat(collaborating.collaborator, is(not(nullValue())));
    }
}

Isis also includes (and automatically uses) a Javassist-based implementation of JMock’s ClassImposteriser interface, so that you can mock out concrete classes as well as interfaces. We’ve provided this rather than JMock’s own cglib-based implementation (which is problematic for us given its own dependencies on asm).

The example tests can be found here

3.3. SOAP Fake Endpoints

No man is an island, and neither are most applications. Chances are that at some point you may need to integrate your Apache Isis application to other external systems, possibly using old-style SOAP web services. The SOAP client in this case could be a domain service within your app, or it might be externalized, eg invoked through a scheduler or using Apache Camel.

While you will want to (of course) perform manual system testing/UAT with a test instance of that external system, it’s also useful to be able to perform unit testing of your SOAP client component.

The SoapEndpointPublishingRule is a simple JUnit rule that allows you to run a fake SOAP endpoint within an unit test.

The (non-ASF) Incode Platform's publishmq module provides a full example of how to integrate and test an Apache Isis application with a (faked out) external system.

3.3.1. SoapEndpointPublishingRule

The idea behind this rule is that you write a fake server endpoint that implements the same WSDL contract as the "real" external system does, but which also exposes additional API to specify responses (or throw exceptions) from SOAP calls. It also typically records the requests and allows these to be queried.

In its setup your unit test and gets the rule to instantiate and publish that fake server endpoint, and then obtains a reference to that server endpoint. It also instantiates the SOAP client, pointing it at the address (that is, a URL) that the fake server endpoint is running on. This way the unit test has control of both the SOAP client and server: the software under test and its collaborator.

In the test methods your unit test sets up expectations on your fake server, and then exercises the SOAP client. The SOAP client calls the fake server, which then responds accordingly. The test can then assert that all expected interactions have occurred.

So that tests don’t take too long to run, the rule puts the fake server endpoints onto a thread-local. Therefore the unit tests should clear up any state on the fake server endpoints.

Your unit test uses the rule by specifying the endpoint class (must have a no-arg constructor):

public class FakeExternalSystemEndpointRuleTest {
    @Rule
    public SoapEndpointPublishingRule serverRule =
        new SoapEndpointPublishingRule(FakeExternalSystemEndpoint.class);         (1)
    private FakeExternalSystemEndpoint fakeServerEndpoint;
    private DemoObject externalSystemContract;                                    (2)
    @Before
    public void setUp() throws Exception {
        fakeServerEndpoint =
            serverRule.getEndpointImplementor(FakeExternalSystemEndpoint.class);  (3)
        final String endpointAddress =
            serverRule.getEndpointAddress(FakeExternalSystemEndpoint.class);      (4)
        final DemoObjectService externalSystemService =                           (5)
                new DemoObjectService(ExternalSystemWsdl.getWsdl());              (6)
        externalSystemContract = externalSystemService.getDemoObjectOverSOAP();
        BindingProvider provider = (BindingProvider) externalSystemContract;
        provider.getRequestContext().put(
                BindingProvider.ENDPOINT_ADDRESS_PROPERTY,
                endpointAddress)
        );
    }
    @Test
    public void happy_case() throws Exception {
        // given
        final Update update = new Update();                              (7)
        ...
        // expect
        final UpdateResponse response = new UpdateResponse();            (8)
        ...
        fakeServerEndpoint.control().setResponse(updateResponse);
        // when
        PostResponse response = externalSystemContract.post(update);     (9)
        // then
        final List<Update> updates =                                     (10)
            fakeServerEndpoint.control().getUpdates();
        ...
    }
}
1 specify the class that implements the endpoint (must have a no-arg constructor)
2 the SOAP contract as defined in WSDL and generated by wsdl2java
3 get hold of the fake server-side endpoint from the rule…​
4 …​ and its endpoint address
5 use factory (also generated by wsdl2java) to create client-side endpoint
6 getWsdl() is a utility method to return a URL for the WSDL (eg from the classpath)
7 create a request object in order to invoke the SOAP web service
8 instruct the fake server endpoint how to respond
9 invoke the web service
10 check the fake server endpoint was correctly invoked etc.

The rule can also host multiple endpoints; just provide multiple classes in the constructor:

@Rule
public SoapEndpointPublishingRule serverRule =
                new SoapEndpointPublishingRule(
                    FakeCustomersEndpoint.class,
                    FakeOrdersEndpoint.class,
                    FakeProductsEndpoint.class);

To lookup a particular endpoint, specify its type:

FakeProductsEndpoint fakeProductsServerEndpoint =
            serverRule.getPublishedEndpoint(FakeProductsEndpoint.class);

The endpoint addresses that the server endpoints run on are determined automatically. If you want more control, then you can call one of SoapEndpointPublishingRule's overloaded constructors, passing in one or more SoapEndpointSpec instances.

3.3.2. XML Marshalling Support

Apache Isis' unit testing support also provides helper JaxbUtil and JaxbMatchers classes. These are useful if you have exampler XML-serialized representations of the SOAP requests and response payloads and want to use these within your tests.

3.4. Maven Configuration

Apache Isis' unit test support is automatically configured if you use the HelloWorld or the SimpleApp archetypes. To set it up manually, update the pom.xml of your domain object model module:

<dependency>
    <groupId>org.apache.isis.core</groupId>
    <artifactId>isis-core-unittestsupport</artifactId>
    <scope>test</scope> (1)
</dependency>
1 Normally test; usual Maven scoping rules apply.

(As of 1.15.0) this can also be done by adding a dependency to org.apache.isis.mavendeps:isis-mavendeps-testing module; see the SimpleApp archetype.

We also recommend that you configure the maven-surefire-plugin to pick up the following class patterns:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-surefire-plugin</artifactId>
    <version>2.10</version>
    <configuration>
        <includes>
            <include>**/*Test.java</include>
            <include>**/*Test_*.java</include>
            <include>**/*Spec*.java</include>
        </includes>
        <excludes>
            <exclude>**/Test*.java</exclude>
            <exclude>**/*ForTesting.java</exclude>
            <exclude>**/*Abstract*.java</exclude>
        </excludes>
        <useFile>true</useFile>
        <printSummary>true</printSummary>
        <outputDirectory>${project.build.directory}/surefire-reports</outputDirectory>
    </configuration>
</plugin>

As of 1.14.0 this can also be done using mavenmixins; see the SimpleApp archetype.

4. Integration Test Support

As discussed in the introductory overview of this chapter, Apache Isis allows you to integration test your domain objects from within JUnit. There are several parts to this:

  • configuring the Apache Isis runtime so it can be bootstrapped (mostly boilerplate)

  • defining a base class to perform said bootstrapping

  • using fixture scripts to set up the app

  • using WrapperFactory so that the UI can be simulated.

We’ll get to all that shortly, but let’s start by taking a look at what a typical integration test looks like.

4.1. Typical Usage

This example adapted from the Isis addons' todoapp (non-ASF). The code we want to test (simplified) is:

public class ToDoItem ... {

    private boolean complete;
    @Property( editing = Editing.DISABLED )
    public boolean isComplete() {
        return complete;
    }
    public void setComplete(final boolean complete) {
        this.complete = complete;
    }

    @Action()
    public ToDoItem completed() {
        setComplete(true);
        ...
        return this;
    }
    public String disableCompleted() {
        return isComplete() ? "Already completed" : null;
    }
    ...
}

We typically put the bootstrapping of Apache Isis into a superclass (AbstractToDoIntegTest below), then subclass as required.

For this test (of the "completed()" action) we need an instance of a ToDoItem that is not yet complete. Here’s the setup:

public class ToDoItemIntegTest extends AbstractToDoIntegTest {

    @Inject
    FixtureScripts fixtureScripts;                              (1)
    @Inject
    ToDoItems toDoItems;                                        (2)
    ToDoItem toDoItem;                                          (3)

    @Before
    public void setUp() throws Exception {
        RecreateToDoItemsForCurrentUser fixtureScript =         (4)
            new RecreateToDoItemsForCurrentUser();
        fixtureScripts.runFixtureScript(fixtureScript, null);
        final List<ToDoItem> all = toDoItems.notYetComplete();  (5)
        toDoItem = wrap(all.get(0));                            (6)
    }
    ...
}
1 the FixtureScripts domain service is injected, providing us with the ability to run fixture scripts
2 likewise, an instance of the ToDoItems domain service is injected. We’ll use this to lookup…​
3 the object under test, held as a field
4 the fixture script for this test; it deletes all existing todo items (for the current user only) and then recreates them
5 we lookup one of the just-created todo items…​
6 and then wrap it so that our interactions with it are as if through the UI

The following code tests the happy case, that a not-yet-completed ToDoItem can be completed by invoking the completed() action:

public class ToDoItemIntegTest ... {
    ...
    public static class Completed extends ToDoItemIntegTest { (1)
        @Test
        public void happyCase() throws Exception {
            // given
            assertThat(toDoItem.isComplete()).isFalse();      (2)
            // when
            toDoItem.completed();
            // then
            assertThat(toDoItem.isComplete()).isTrue();
        }
        ...
    }
}
1 the idiom we follow is to use nested static classes to identify the class responsibility being tested
2 the todoapp uses AssertJ.

What about when a todo item is already completed? The disableCompleted() method in the class says that it shouldn’t be allowed (the action would be greyed out in the UI with an appropriate tooltip). The following test verifies this:

        @Test
        public void cannotCompleteIfAlreadyCompleted() throws Exception {
            // given
            unwrap(toDoItem).setComplete(true);                     (1)
            // expect
            expectedExceptions.expectMessage("Already completed");  (2)
            // when
            toDoItem.completed();
        }
1 we unwrap the domain object in order to set its state directly
2 the expectedExceptions JUnit rule (defined by a superclass) verifies that the appropiate exception is indeed thrown (in the "when")

And what about the fact that the underlying "complete" property is disabled (the @Disabled annotation?). If the ToDoItem is put into edit mode in the UI, the complete checkbox should remain read-only. Here’s a verify similar test that verifies this also:

        @Test
        public void cannotSetPropertyDirectly() throws Exception {
            // expect
            expectedExceptions.expectMessage("Always disabled");  (1)
            // when
            toDoItem.setComplete(true);
        }
1 again we use the exceptedExceptions rule.

4.2. Bootstrapping

Integration tests instantiate an Apache Isis "runtime" (as a singleton) within a JUnit test. Because (depending on the size of your app) it takes a little time to bootstrap Apache Isis, the framework caches the runtime on a thread-local from one test to the next.

Newer releases of the framework reduce the amount of boilerplate to do this; this guide documents multiple versions.

The example code in this section is taken from the app generated by the SimpleApp archetype.

4.2.1. 1.15.0 onwards

In 1.15.0 the bootstrapping is accomplished using a combination of AppManifestAbstract (a framework-provided implementation of AppManifest) and IntegrationTestAbstract2 superclass.

For example, the SimpleApp archetype's integration tests all inherit from this class:

public abstract class DomainAppIntegTestAbstract extends IntegrationTestAbstract2 {

    @BeforeClass
    public static void initSystem() {
        bootstrapUsing(new DomainAppAppManifest());
    }

}

where DomainAppAppManifest in turn is:

public class DomainAppAppManifest extends AppManifestAbstract {

    public static final Builder BUILDER = Builder.forModules(
                    SimpleModuleDomSubmodule.class,
                    DomainAppApplicationModuleFixtureSubmodule.class,
                    DomainAppApplicationModuleServicesSubmodule.class
            )
            .withConfigurationPropertiesFile(DomainAppAppManifest.class,
                    "isis.properties",
                    "authentication_shiro.properties",
                    "persistor_datanucleus.properties",
                    "viewer_restfulobjects.properties",
                    "viewer_wicket.properties"
            ).withAuthMechanism("shiro");

    public DomainAppAppManifest() {
        super(BUILDER);
    }
}

The AppManifestAbstract class (which is also used to bootstrap the regular app as well as integration tests) is discussed further here, while the IntegrationTestAbstract2 class is discussed further here.

4.2.2. 1.13.0

In 1.13.0 the bootstrapping itself is typically performed by a "system initializer" class. This is responsible for instantiating the Apache Isis runtime (based on a provided AppManifest) and binding it to a thread-local.

The AppManifest.Util class allows configuration properties for integration testing to be defined (replacing the IsisConfigurationForJdoIntegTests of earlier releases).

For example:

public class DomainAppSystemInitializer {
    public static void initIsft() {
        IsisSystemForTest isft = IsisSystemForTest.getElseNull();
        if(isft == null) {
            isft = new IsisSystemForTest.Builder()
                    .withLoggingAt(org.apache.log4j.Level.INFO)
                    .with(new DomainAppAppManifest() {
                        @Override
                        public Map<String, String> getConfigurationProperties() {
                            final Map<String, String> map = Maps.newHashMap();
                            Util.withJavaxJdoRunInMemoryProperties(map);
                            Util.withDataNucleusProperties(map);
                            Util.withIsisIntegTestProperties(map);
                            return map;
                        }
                    })
                    .build();
            isft.setUpSystem();
            IsisSystemForTest.set(isft);
        }
    }
}

The above code uses the AppManifest.Util helper class, which provides a number of static methods that can be used to set up configuration properties appropriate for integration testing (eg run using an in-memory database). This allows the responsibility of returning the configuration properties to belong exclusively to the AppManifest.

There are three such static methods:

public interface AppManifest {
  ...
  public static class Util {
    public static Map<String,String>
        withJavaxJdoRunInMemoryProperties(Map<String, String> map) { ... }   (1)
    public static Map<String,String>
        withDataNucleusProperties(Map<String, String> map) { ... }           (2)
    public static Map<String,String>
        withIsisIntegTestProperties(Map<String, String> map) { ... }         (3)
  }
}
1 sets up the javax.jdo.option.Connection* properties so as to run against an in-memory instance of HSQLDB
2 sets up DataNucleus to automatically create the databse schema, as well as a number of other standard properties (disable persistence by reachability, support mixed case identifiers, disable level 2 cache)
3 sets up standard properties for the Apache Isis framework, most specifically to enable fixtures to be installed.

4.2.3. 1.9.0

In 1.9.0 the AppManifest was introduced as mechanism to specify all parts (domain code, framework components, configuation properties) that make up a running application.

The suggested way to use this concept was using a "system initializer" class. This uses a IsisConfigurationForJdoIntegTests class to bring together the configuration properties (discussed further here) to bootstrap the application.

For example:

public class DomainAppSystemInitializer {
    public static void initIsft() {
        IsisSystemForTest isft = IsisSystemForTest.getElseNull();
        if(isft == null) {
            isft = new IsisSystemForTest.Builder()
                    .withLoggingAt(org.apache.log4j.Level.INFO)
                    .with(new DomainAppAppManifest())
                    .with(new IsisConfigurationForJdoIntegTests())
                    .build()
                    .setUpSystem();
            IsisSystemForTest.set(isft);
        }
    }
}

where DomainAppAppManifest in turn is defined as:

public class DomainAppAppManifest implements AppManifest {
    @Override
    public List<Class<?>> getModules() {
        return Arrays.asList(
                domainapp.dom.DomainAppDomainModule.class,
                domainapp.fixture.DomainAppFixtureModule.class,
                domainapp.app.DomainAppAppModule.class
        );
    }
    ...
}

Further details on bootstrapping with the AppManifest can be found in the reference guide.

4.2.4. 1.8.0 and earlier

Prior to 1.9.0, the services and entities had to be specified in two separate locations. The suggested way to do this was to introduce a subclass of the IsisSystemForTest.Builder class:

private static class DomainAppSystemBuilder extends IsisSystemForTest.Builder {      (1)
    public DomainAppSystemBuilder() {
        withLoggingAt(org.apache.log4j.Level.INFO);
        with(testConfiguration());
        with(new DataNucleusPersistenceMechanismInstaller());                        (2)
        withServicesIn( "domainapp" );                                               (3)
    }
    private static IsisConfiguration testConfiguration() {
        final IsisConfigurationForJdoIntegTests testConfiguration =
            new IsisConfigurationForJdoIntegTests();                                 (4)
        testConfiguration.addRegisterEntitiesPackagePrefix("domainapp.dom.modules"); (5)
        return testConfiguration;
    }
}
1 subclass the framework-provided IsisSystemForTest.Builder.
2 equivalent to isis.persistor=datanucleus in isis.properties
3 specify the isis.services key in isis.properties (where "domainapp" is the base package for all classes within the app)
4 IsisConfigurationForJdoIntegTests has pre-canned configuration for using an in-memory HSQLDB and other standard settings; more on this below.
5 equivalent to isis.persistor.datanucleus.RegisterEntities.packagePrefix key (typically in persistor_datanucleus.properties)

This builder could then be used within the system initializer:

public class DomainAppSystemInitializer {
    public static void initIsft() {
        IsisSystemForTest isft = IsisSystemForTest.getElseNull();
        if(isft == null) {
            isft = new DomainAppSystemBuilder()    (1)
                            .build()
                            .setUpSystem();
            IsisSystemForTest.set(isft);           (2)
        }
    }
    private static class DomainAppSystemBuilder
        extends IsisSystemForTest.Builder { ... }
}
1 instantiates and initializes the Apache Isis runtime (the IsisSystemForTest class)
2 binds the runtime to a thread-local.

4.3. Abstract class

When writing integration tests, it’s easiest to inherit from a base class:

  • as of (1.15.0), use IntegrationTestAbstract2

  • for earlier releases, use (its superclass) IntegrationTestAbstract.

This base class bootstraps the framework (caching the framework on a thread-local), and provides various utility methods and framework-provided services for use by your application’s subclass tests.

4.3.1. IntegrationTestAbstract2

(As of 1.15.0) we recommend that your integration tests inherit from Apache Isis' IntegrationTestAbstract2 class:

public abstract class DomainAppIntegTest extends IntegrationTestAbstract2 {
    ...
}

Although not mandatory, this provides a number of helper/convenience methods and JUnit rules:

    @Rule
    public IsisTransactionRule isisTransactionRule =                         (1)
        new IsisTransactionRule();
    @Rule
    public JUnitRuleMockery2 context =                                       (2)
        JUnitRuleMockery2.createFor(Mode.INTERFACES_AND_CLASSES);
    @Rule
    public ExpectedException expectedExceptions =                            (3)
        ExpectedException.none();
    @Rule
    public ExceptionRecognizerTranslate exceptionRecognizerTranslations =    (4)
        ExceptionRecognizerTranslate.create();
1 ensures an Apache Isis session/transaction running for each test
2 sets up a JMock context (using Apache Isis' extension to JMock as described in JMock Extensions.
3 standard JUnit rule for writing tests that throw exceptions
4 to capture messages that require translation, as described in i18 support.

All of these rules could be inlined in your own base class; as we say, they are a convenience.

The IntegrationTestAbstract2 also provides a number of helper/convenience methods, though most of these have been deprecated because the functionality they expose is now readily accessible through various domain services; most notably these are:

4.3.2. IntegrationTestAbstract

For earlier releases we recommend that your base class inherit from Apache Isis' IntegrationTestAbstract class:

public abstract class DomainAppIntegTest extends IntegrationTestAbstract {
    ...
}

This provides most of the benefits of IntegrationTestAbstract2 (it is the latter’s superclass, in fact), but the bootstrapping is more verbose.

4.4. Configuration Properties

The recommended way to run integration tests is against an HSQLDB in-memory database. This can be done using the application’s usual AppManifest, and then overriding JDBC URL and similar.

Different releases of the framework have provided differing ways to accomplish this. (As of 1.15.0) using IntegrationTestAbstract2’s `bootstrapUsing method will make these configuration properties as the default. In earlier releases either the helper methods in AppManifest.Util class or the IsisConfigurationForJdoIntegTests (implementation of IsisConfiguration) can be used.

Whichever approach is used, these are the configuration properties that will be overridden:

Table 1. Default Configuration Properties for Integration Tests
Property Value Description

isis.persistor.datanucleus.impl.
javax.jdo.option.ConnectionURL

jdbc:hsqldb:mem:test

JDBC URL

isis.persistor.datanucleus.impl.
javax.jdo.option.ConnectionDriverName

org.hsqldb.jdbcDriver

JDBC Driver

isis.persistor.datanucleus.impl.
javax.jdo.option.ConnectionUserName

sa

Username

isis.persistor.datanucleus.impl.
javax.jdo.option.ConnectionPassword

<empty string>

Password, possibly encrypted (see datanucleus.ConnectionPasswordEncrypter, below).

isis.persistor.datanucleus.impl.
datanucleus.ConnectionPasswordEncrypter

<empty string>

Specify the datanucleus.ConnectionPasswordDecrypter implementation used to decrypt the password.

See the DataNucleus documentation for further details.

isis.persistor.datanucleus.impl.
datanucleus.schema.autoCreateAll

true

Recreate DB for each test run (an in-memory database)

isis.persistor.datanucleus.impl.
datanucleus.schema.validateAll

false

Disable validations (minimize bootstrap time)

isis.persistor.datanucleus.impl.
datanucleus.persistenceByReachabilityAtCommit

false

As per WEB-INF/persistor_datanucleus.properties

isis.persistor.datanucleus.impl.
datanucleus.identifier.case

MixedCase

As per WEB-INF/persistor_datanucleus.properties

isis.persistor.datanucleus.impl.
datanucleus.cache.level2.type

none

As per WEB-INF/persistor_datanucleus.properties

isis.persistor.datanucleus.impl.
datanucleus.cache.level2.mode

ENABLE_SELECTIVE

As per WEB-INF/persistor_datanucleus.properties

isis.persistor.datanucleus.
install-fixtures

true

Automatically install any fixtures that might have been registered

isis.persistor.
enforceSafeSemantics

false

isis.deploymentType

server_prototype

4.5. Wrapper Factory

The WrapperFactory service is responsible for wrapping a domain object in a dynamic proxy, of the same type as the object being proxied. And the role of this wrapper is to simulate the UI.

WrapperFactory uses javassist to perform its magic; this is the same technology that ORMs such as Hibernate use to manage lazy loading/dirty tracking (DataNucleus uses a different mechanism).

It does this by allowing through method invocations that would be allowed if the user were interacting with the domain object through one of the viewers, but throwing an exception if the user attempts to interact with the domain object in a way that would not be possible if using the UI.

The mechanics are as follows:

  1. the integration test calls the WrapperFactory to obtain a wrapper for the domain object under test. This is usually done in the test’s setUp() method.

  2. the test calls the methods on the wrapper rather than the domain object itself

  3. the wrapper performs a reverse lookup from the method invoked (a regular java.lang.reflect.Method instance) into the Apache Isis metamodel

  4. (like a viewer), the wrapper then performs the "see it/use it/do it" checks, checking that the member is visible, that it is enabled and (if there are arguments) that the arguments are valid

  5. if the business rule checks pass, then the underlying member is invoked. Otherwise an exception is thrown.

The type of exception depends upon what sort of check failed. It’s straightforward enough: if the member is invisible then a HiddenException is thrown; if it’s not usable then you’ll get a DisabledException, if the args are not valid then catch an InvalidException.

wrapper factory

Let’s look in a bit more detail at what the test can do with the wrapper.

4.5.1. Wrapping and Unwrapping

Wrapping a domain object is very straightforward; simply call WrapperFactory#wrap(…​).

For example:

Customer customer = ...;
Customer wrappedCustomer = wrapperFactory.wrap(wrappedCustomer);

Going the other way — getting hold of the underlying (wrapped) domain object — is just as easy; just call WrapperFactory#unwrap(…​).

For example:

Customer wrappedCustomer = ...;
Customer customer = wrapperFactory.unwrap(wrappedCustomer);

If you prefer, you also can get the underlying object from the wrapper itself, by downcasting to WrappingObject and calling __isis_wrapped() method:

Customer wrappedCustomer = ...;
Customer customer = (Customer)((WrappingObject)wrappedCustomer).__isis_wrapped());

We’re not sure that’s any easier (in fact we’re certain it looks rather obscure). Stick with calling unwrap(…​)!

4.5.2. Using the wrapper

As the wrapper is intended to simulate the UI, only those methods that correspond to the "primary" methods of the domain object’s members are allowed to be called. That means:

  • for object properties the test can call the getter or setter method

  • for object collections the test can call the getter.

    If there is a supporting addTo…​() or removeFrom…​() method, then these can be called. It can also call add(…​) or remove(…​) on the collection (returned by the gettter) itself.

    In this respect the wrapper is more functional than the Wicket viewer (which does not expose the ability to mutate collections directly).

  • for object actions the test can call the action method itself.

As a convenience, we also allow the test to call any default…​(),choices…​() or autoComplete…​() method. These are often useful for obtaining a valid value to use.

What the test can’t call is any of the remaining supporting methods, such as hide…​(), disable…​() or validate…​(). That’s because their value is implied by the exception being thrown.

The wrapper does also allow the object’s title() method or its toString() , however this is little use for objects whose title is built up using the @Title annotation. Instead, we recommend that your test verifies an object’s title by calling DomainObjectContainer#titleOf(…​) method.

4.5.3. Firing Domain Events

As well as enforcing business rules, the wrapper has another important feature, namely that it will cause domain events to be fired.

For example, if we have an action annotated with @Action(domainEvent=…​):

public class ToDoItem ... {
    @Action(
            domainEvent =CompletedEvent.class
    )
    public ToDoItem completed() { ... }
    ...
}

then invoking the action through the proxy will cause the event (CompletedEvent above) to be fired to any subscribers. A test might therefore look like:

@Inject
private EventBusService eventBusService;                                          (1)

@Test
public void subscriberReceivesEvents() throws Exception {

    // given
    final ToDoItem.CompletedEvent[] evHolder = new ToDoItem.CompletedEvent[1];    (2)
    eventBusService.register(new Object() {
        @Subscribe
        public void on(final ToDoItem.CompletedEvent ev) {                        (3)
            evHolder[0] = ev;
        }
    });

    // when
    toDoItem.completed();                                                         (4)

    // then
    then(evHolder[0].getSource()).isEqualTo(unwrap(toDoItem));                    (5)
    then(evHolder[0].getIdentifier().getMemberName()).isEqualTo("completed");
}
1 inject EventBusService into this test
2 holder for subscriber to capture event to
3 subscriber’s callback, using the guava subscriber syntax
4 invoking the domain object using the wrapper
5 assert that the event was populated

The wrapper will also fire domain events for properties (if annotated with @Property(domainEvent=…​)) or collections (if annotated with @Collection(domainEvent=…​)).

It isn’t possible to use the WrapperFactory in a unit test, because there needs to be a running instance of Apache Isis that holds the metamodel.

4.6. Maven Configuration

Apache Isis' integration test support is automatically configured if you use the SimpleApp archetype. To set it up manually, update the pom.xml of your domain object model module:

<dependency>
    <groupId>org.apache.isis.core</groupId>
    <artifactId>isis-core-integtestsupport</artifactId>
</dependency>
<dependency>
    <groupId>org.apache.isis.core</groupId>
    <artifactId>isis-core-wrapper</artifactId>
</dependency>

(As of 1.15.0) this can also be done by adding a dependency to org.apache.isis.mavendeps:isis-mavendeps-testing module; see the SimpleApp archetype.

We also recommend that you configure the maven-surefire-plugin to pick up the following class patterns:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-surefire-plugin</artifactId>
    <version>2.10</version>
    <configuration>
        <includes>
            <include>**/*Test.java</include>
            <include>**/*Test_*.java</include>
            <include>**/*Spec*.java</include>
        </includes>
        <excludes>
            <exclude>**/Test*.java</exclude>
            <exclude>**/*ForTesting.java</exclude>
            <exclude>**/*Abstract*.java</exclude>
        </excludes>
        <useFile>true</useFile>
        <printSummary>true</printSummary>
        <outputDirectory>${project.build.directory}/surefire-reports</outputDirectory>
    </configuration>
</plugin>

As of 1.14.0 this can also be done using mavenmixins; see the SimpleApp archetype.

5. BDD Spec Support

Behaviour-driven design (BDD) redefines testing not as an after-the-fact "let’s check the system works", but rather as a means to work with the domain expert to (a) specify the behaviour of the feature before starting implementation, and (b) provide a means that the domain expert can verify the feature after it has been implemented.

Since domain experts are usually non-technical (at least, they are unlikely to be able to read or want to learn how to read JUnit/Java code), then applying BDD typically requires writing specifications in using structured English text and (ASCII) tables. The BDD tooling parses this text and uses it to actually interact with the system under test. As a byproduct the BDD frameworks generate readable output of some form; this is often an annotated version of the original specification, marked up to indicate which specifications passed, which have failed. This readable output is a form of "living documentation"; it captures the actual behaviour of the system, and so is guaranteed to be accurate.

There are many BDD tools out there; Apache Isis provides an integration with Cucumber JVM (see also the github site):

5.1. How it works

At a high level, here’s how Cucumber works

  • specifications are written in the Gherkin DSL, following the "given/when/then" format.

  • Cucumber-JVM itself is a JUnit runner, and searches for feature files on the classpath.

  • These in turn are matched to step definitions through regular expressions.

    It is the step definitions (the "glue") that exercise the system.

The code that goes in step definitions is broadly the same as the code that goes in an integration test method. One benefit of using step definitions (rather than integration tests) is that the step definitions are reusable across scenarios, so there may be less code overall to maintain. For example, if you have a step definition that maps to "given an uncompleted todo item", then this can be used for all the scenarios that start with that as their precondition.

5.2. Key classes

There are some key framework classes that make up the spec support; these are discussed below.

some of these are also used by Apache Isis' Integration Test support.

5.2.1. IsisSystemForTest

The IsisSystemForTest class allows a complete running instance of Apache Isis to be bootstrapped (with the JDO objectstore); this is then held on a a ThreadLocal from one test to another.

Typically bootstrapping code is used to lazily instantiate the IsisSystemForTest once and once only. The mechanism for doing this is line-for-line identical in both BDD step defs and integration tests.

5.2.2. ScenarioExecution

The ScenarioExecution provides a context for a scenario that is being executed. It is Cucumber that determines which step definitions are run, and in which order, and so state cannot be passed between step definitions using local variables or instance variables. Instead the ScenarioExecution acts like a hashmap, allowing each step to put data (eg "given an uncompleted todoitem") into the map or get data ("when I complete the todoitem") from the map. This is done using the putVar(…​) and getVar(…​) methods.

This corresponds broadly to the "World" object in Ruby-flavoured Cucumber.

The ScenarioExecution also provids access to the configured domain services (using the service(…​) method) and the DomainObjectContainer (through the container() method).

This could probably be refactored; Cucumber JVM provides automatic dependency injection into setp definitions, but Apache Isis does not currently leverage or exploit this capability.

Like the IsisSystemForTest class, the ScenarioExecution class binds an instance of itself onto a ThreadLocal. It can then be accessed in BDD step definitions using ScenarioExecution.current() static method.

5.2.3. WrapperFactory

As with integration tests, the UI can be simulated by "wrapping" each domain object in a proxy using the WrapperFactory.

5.2.4. CukeGlueAbstract

The CukeGlueAbstract acts as a convenience superclass for writing BDD step definitions (analogous to the IntegrationTestAbstract for integation tests). Underneath the covers it delegates to an underlying ScenarioExecution.

5.3. Writing a BDD spec

BDD specifications contain:

  • a XxxSpec.feature file, describing the feature and the scenarios (given/when/then)s that constitute its acceptance criteria

  • a RunSpecs.java class file to run the specification (all boilerplate). This will run all .feature files in the same package or subpackages.

  • one or several XxxGlue constituting the step definitions to be matched against.

    The "glue" (step definitions) are intended to be reused across features. We therefore recommend that they reside in a separate package, and are organized by the entity type upon which they act.

    For example, given a feature that involves Customer and Order, have the step definitions pertaining to Customer reside in CustomerGlue, and the step definitions pertaining to Order reside in OrderGlue.

    The glue attribute of the Cucumber-JVM JUnit runner eallows you to indicate which package(s) should be recursively searched to find any glue.

  • a system initializer class. You can reuse the system initializer from any integration tests (as described in Integration Test Support, bootstrapping section).

Here’s an example of a feature from the SimpleApp archetype:

@SimpleObjectsFixture
Feature: List and Create New Simple Objects

  @integration
  Scenario: Existing simple objects can be listed and new ones created
    Given there are initially 3 simple objects
    When  I create a new simple object
    Then  there are 4 simple objects

The @SimpleObjectsFixture is a custom tag we’ve specified to indicate the prerequisite fixtures to be loaded; more on this in a moment. The @integration tag, meanwhile, says that this feature should be run with integration-level scope.

Although BDD specs are most commonly used for end-to-end tests (ie at the same scope as an integration test), the two concerns (expressability of a test to a business person vs granularity of the test) should not be conflated. There are a couple of good blog posts discussing this. The basic idea is to avoid the overhead of a heavy-duty integration test if possible.

Apache Isis does also support running BDD specs in unit test mode; by annotating the scenario with the @unit (rather than @integration tag). When running under unit-level scope, the Apache Isis system is not instantiated. Instead, the ScenarioExecution class returns JMock mocks (except for the WrapperFactory, if configured).

To support unit testing scope Apache Isis provides the InMemoryDB class; a glorified hashmap of "persisted" objects. Use of this utility class is optional.

Writing a BDD spec that supports both modes of operation therefore takes more effort and we expect most users interested in BDD will use integration-testing scope; for these reasons we have chosen not to include unit-testing support in the SimpleApp archetype. For those who do require faster-executing test suite, it’s worthwhile knowing that Apache Isis can support this.

The RunSpecs class to run this feature (and any other features in this package or subpackages) is just boilerplate

@RunWith(Cucumber.class)
@CucumberOptions(
        format = {
                "html:target/cucumber-html-report"
                ,"json:target/cucumber.json"
        },
        glue={"classpath:domainapp.integtests.specglue"},
        strict = true,
        tags = { "~@backlog", "~@ignore" })
public class RunSpecs {
    // intentionally empty
}

The JSON formatter allows integration with enhanced reports. (Commented out) configuration for this is provided in the SimpleApp archetype.

The bootstrapping of Apache Isis can be moved into a BootstrappingGlue step definition:

public class BootstrappingGlue extends CukeGlueAbstract {
    @Before(value={"@integration"}, order=100)
    public void beforeScenarioIntegrationScope() {
        org.apache.log4j.PropertyConfigurator.configure("logging.properties");
        SimpleAppSystemInitializer.initIsft();

        before(ScenarioExecutionScope.INTEGRATION);
    }
    @After
    public void afterScenario(cucumber.api.Scenario sc) {
        assertMocksSatisfied();
        after(sc);
    }
}

The fixture to run also lives in its own step definition, CatalogOfFixturesGlue:

public class CatalogOfFixturesGlue extends CukeGlueAbstract {
    @Before(value={"@integration", "@SimpleObjectsFixture"}, order=20000)
    public void integrationFixtures() throws Throwable {
        scenarioExecution().install(new RecreateSimpleObjects());
    }
}

Note that this is annotated with a tag (@SimpleObjectsFixture) so that the correct fixture runs. (We might have a whole variety of these).

The step definitions pertaining to SimpleObject domain entity then reside in the SimpleObjectGlue class. This is where the heavy lifting gets done:

public class SimpleObjectGlue extends CukeGlueAbstract {
    @Given("^there are.* (\\d+) simple objects$")
    public void there_are_N_simple_objects(int n) throws Throwable {
        try {
            final List<SimpleObject> findAll = service(SimpleObjects.class).listAll();
            assertThat(findAll.size(), is(n));
            putVar("list", "all", findAll);

        } finally {
            assertMocksSatisfied();
        }
    }
    @When("^I create a new simple object$")
    public void I_create_a_new_simple_object() throws Throwable {
        service(SimpleObjects.class).create(UUID.randomUUID().toString());
    }
}

If using Java 8, note that Cucumber JVM supports a simplified syntax using lambdas.

5.4. BDD Tooling

To help write feature files and generate step definitions, we recommend Roberto Lo Giacco’s Eclipse plugin. For more information, see Dan’s short blog post. It works very well. Of interest: this is implemented using XText.

5.5. Maven Configuration

Apache Isis' BDD spec support is automatically configured if you use the SimpleApp archetype. To set it up manually, update the pom.xml of your domain object model module:

<dependency>
    <groupId>org.apache.isis.core</groupId>
    <artifactId>isis-core-specsupport</artifactId>
    <scope>test</scope> (1)
</dependency>
1 Normally test; usual Maven scoping rules apply.

We also recommend that you configure the maven-surefire-plugin to pick up the following class patterns:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-surefire-plugin</artifactId>
    <version>2.10</version>
    <configuration>
        <includes>
            <include>**/*Test.java</include>
            <include>**/*Test_*.java</include>
            <include>**/*Spec*.java</include>
        </includes>
        <excludes>
            <exclude>**/Test*.java</exclude>
            <exclude>**/*ForTesting.java</exclude>
            <exclude>**/*Abstract*.java</exclude>
        </excludes>
        <useFile>true</useFile>
        <printSummary>true</printSummary>
        <outputDirectory>${project.build.directory}/surefire-reports</outputDirectory>
    </configuration>
</plugin>

As of 1.14.0, this configuration has been replaced to use mavenmixins.

You may also find it more convenient to place the .feature files in src/test/java, rather than src/test/resources. If you wish to do this, then your integtest module’s pom.xml must contain:

<build>
    <testResources>
        <testResource>
            <filtering>false</filtering>
            <directory>src/test/resources</directory>
        </testResource>
        <testResource>
            <filtering>false</filtering>
            <directory>src/test/java</directory>
            <includes>
                <include>**</include>
            </includes>
            <excludes>
                <exclude>**/*.java</exclude>
            </excludes>
        </testResource>
    </testResources>
</build>

6. Fixture Scripts

When writing integration tests (and implementing the glue for BDD specs) it can be difficult to keep the "given" short; there could be a lot of prerequisite data that needs to exist before you can actually exercise your system. Moreover, however we do set up that data, but we also want to do so in a way that is resilient to the system changing over time.

On a very simple system you could probably get away with using SQL to insert directly into the database, or you could use a toolkit such as dbunit to upload data from flat files. Such approaches aren’t particularly maintainable though. If in the future the domain entities (and therefore corresponding database tables) change their structure, then all of those data sets will need updating.

Even more significantly, there’s no way to guarantee that the data that’s being loaded is logically consistent with the business behaviour of the domain objects themselves. That is, there’s nothing to stop your test from putting data into the database that would be invalid if one attempted to add it through the app.

The solution that Apache Isis provides is a small library called fixture scripts. A fixture script is basically a wrapper for executing arbitrary work, but that work almost always invoking a business action.

If you want to learn more on this topic (with live coding!), check out this presentation given at BDD Exchange 2014.

There is another benefit to Apache Isis' fixture script approach; the fixtures can be (in prototyping mode) run from your application. This means that fixture scripts can actually help all the way through the development lifecycle:

  • when specifying a new feature, you can write a fixture script to get the system into the "given" state, and then start exploring the required functionality with the domain expert actually within the application

    And if you can’t write a fixture script for the story, it probably means that there’s some prerequisite feature that needs implementing that you hadn’t previously recognized

  • when the developer implements the story, s/he has a precanned script to run when they manually verify the functionality works

  • when the developer automates the story’s acceptance test as an integration test, they already have the "given" part of the test implemented

  • when you want to pass the feature over to the QA/tester for additional manual exploratory testing, they have a fixture script to get them to a jumping off point for their explorations

  • when you want to demonstrate the implemented feature to your domain expert, your demo can use the fixture script so you don’t bore your audience in performing lots of boring setup before getting to the actual feature

  • when you want to roll out training to your users, you can write fixture scripts as part of their training exercises

The following sections explain the API and how to go about using the API.

6.1. API and Usage

There are two parts to using fixture scripts: the FixtureScripts domain service class, and the FixtureScript view model class:

  • The role of the FixtureScripts domain service is to locate all fixture scripts from the classpath and to let them be invoked, either from an integration test/BDD spec or from the UI of your Isis app.

  • The role of FixtureScript meanwhile is to subclass for each of the scenarios that you want to define. You can also subclass from FixtureScript to create helpers; more on this below.

Let’s look at FixtureScripts domain service in more detail first.

6.1.1. FixtureScripts

There are two ways in which you can provide a FixtureScripts service.

The original (pre-1.9.0) approach is to subclass subclass FixtureScripts domain service, with your subclass specifying which package to search for. Various other settings can also be provided, and - being a custom class - you can also add in additional actions. A common example is to provide a "one-shot" action to recreate a standard demo set of objects.

As of 1.9.0 there is an alternative design. Instead of subclassing FixtureScripts you instead implement the FixtureScriptsSpecificationProvider SPI. (As its name suggests), this provides a FixtureScriptsSpecification object that contains the same information as would otherwise have been in the FixtureScripts subclass.

The actual implementation of the FixtureScripts service is then provided by the framework itself, namely the FixtureScriptsDefault domain service, annotated to be rendered on the secondary "Prototyping" menu. This uses the FixtureScriptsSpecificationProvider to adjust itself accordinly.

For example, here’s the FixtureScriptsSpecificationProvider service that’s generated by the SimpleApp archetype:

@DomainService(nature = NatureOfService.DOMAIN)
public class DomainAppFixturesProvider implements FixtureScriptsSpecificationProvider {
    @Override
    public FixtureScriptsSpecification getSpecification() {
        return FixtureScriptsSpecification
                .builder(DomainAppFixturesProvider.class)                                       (1)
                .with(FixtureScripts.MultipleExecutionStrategy.EXECUTE)                         (2)
                .withRunScriptDefault(RecreateSimpleObjects.class)                              (3)
                .withRunScriptDropDown(FixtureScriptsSpecification.DropDownPolicy.CHOICES)      (4)
                .withRecreate(RecreateSimpleObjects.class)                                      (5)
                .build();
    }
}
1 search for all fixture scripts under the package containing this class
2 if the same fixture script (class) is encountered more than once, then run anyway; more on this in Organizing Fixture scripts], below.
3 specify the fixture script class to provide as the default for the service’s "run fixture script" action
4 whether the service’s "run fixture script" action should display other fixture scripts using a choices drop down or (if there are very many of them) using an auto-complete
5 if present, enables a "recreate objects and return first" action to be displayed in the UI

The benefit of this design - decoupling the responsibilities of the superclass and the subclass - is that it ensures that there is always an instance of FixtureScripts available, even if the application itself doesn’t provide one. .

By way of comparison, if using the older pre-1.9.0 approach then you would create a subclass:

@DomainService
@DomainServiceLayout(
        menuBar = DomainServiceLayout.MenuBar.SECONDARY,           (1)
        named="Prototyping",                                       (2)
        menuOrder = "500"
)
public class DomainAppFixturesService extends FixtureScripts {     (3)
    public DomainAppFixturesService() {
        super(
            "domainapp",                                           (4)
            MultipleExecutionStrategy.EXECUTE);                    (5)
    }
    @Override
    public FixtureScript default0RunFixtureScript() {
        return findFixtureScriptFor(RecreateSimpleObjects.class);  (6)
    }
    @Override
    public List<FixtureScript> choices0RunFixtureScript() {        (7)
        return super.choices0RunFixtureScript();
    }
}
1 in the UI, render the on the right hand side (secondary) menu bar…​
2 …​ under the "Prototyping" menu
3 inherit from org.apache.isis.applib.fixturescripts.FixtureScripts
4 search for all fixture scripts under the "domainapp" package; in your code this would probably be "com.mycompany.myapp" or similar
5 if the same fixture script (class) is encountered more than once, then run anyway; more on this in Organizing Fixture scripts], below.
6 (optional) specify a default fixture script to run, in this case RecreateSimpleObjects fixture script (see below)
7 make all fixture scripts found available as a drop-down (by increasing the visibility of this method to public)

This isn’t quite equivalent; you would need to write additional code to support the "recreate objects and return first" action, for example.

Either way, here’s how the domain service looks like in the UI:

prototyping menu

and here’s what the runFixtureScript action prompt looks like:

prompt

when this is executed, the resultant objects (actually, instances of FixtureResult`) are shown in the UI:

result list

If you had defined many fixture scripts then a drop-down might become unwieldy, in which case your code would probably override the autoComplete…​()) instead:

    @Override
    public List<FixtureScript> autoComplete0RunFixtureScript(final @MinLength(1) String searchArg) {
        return super.autoComplete0RunFixtureScript(searchArg);
    }

You are free, of course, to add additional "convenience" actions into it if you wish for the most commonly used/demo’d setups ; you’ll find that the SimpleApp archetype adds this additional action:

    @Action(
            restrictTo = RestrictTo.PROTOTYPING
    )
    @ActionLayout(
            cssClassFa="fa fa-refresh"
    )
    @MemberOrder(sequence="20")
    public Object recreateObjectsAndReturnFirst() {
        final List<FixtureResult> run = findFixtureScriptFor(RecreateSimpleObjects.class).run(null);
        return run.get(0).getObject();
    }

Let’s now look at the FixtureScript class, where there’s a bit more going on.

6.1.2. FixtureScript

A fixture script is ultimately just a block of code that can be executed, so it’s up to you how you implement it to set up the system. However, we strongly recommend that you use it to invoke actions on business objects, in essence to replay what a real-life user would have done. That way, the fixture script will remain valid even if the underlying implementation of the system changes in the future.

Here’s the RecreateSimpleObjects fixture script from the SimpleApp archetype:

public class RecreateSimpleObjects extends FixtureScript {                   (1)

    public final List<String> NAMES = Collections.unmodifiableList(Arrays.asList(
            "Foo", "Bar", "Baz", "Frodo", "Froyo",
            "Fizz", "Bip", "Bop", "Bang", "Boo"));                           (2)
    public RecreateSimpleObjects() {
        withDiscoverability(Discoverability.DISCOVERABLE);                   (3)
    }
    private Integer number;                                                  (4)
    public Integer getNumber() { return number; }
    public RecreateSimpleObjects setNumber(final Integer number) {
        this.number = number;
        return this;
    }
    private final List<SimpleObject> simpleObjects = Lists.newArrayList();   (5)
    public List<SimpleObject> getSimpleObjects() {
        return simpleObjects;
    }
    @Override
    protected void execute(final ExecutionContext ec) {          (6)
        // defaults
        final int number = defaultParam("number", ec, 3);        (7)
        // validate
        if(number < 0 || number > NAMES.size()) {
            throw new IllegalArgumentException(
                String.format("number must be in range [0,%d)", NAMES.size()));
        }
        // execute
        ec.executeChild(this, new SimpleObjectsTearDown());      (8)
        for (int i = 0; i < number; i++) {
            final SimpleObjectCreate fs =
                new SimpleObjectCreate().setName(NAMES.get(i));
            ec.executeChild(this, fs.getName(), fs);             (9)
            simpleObjects.add(fs.getSimpleObject());             (10)
        }
    }
}
1 inherit from org.apache.isis.applib.fixturescripts.FixtureScript
2 a hard-coded list of values for the names. Note that the (non-ASF) Incode Platform's fakedata module could also have been used
3 whether the script is "discoverable"; in other words whether it should be rendered in the drop-down by the FixtureScripts service
4 input property: the number of objects to create, up to 10; for the calling test to specify, but note this is optional and has a default (see below). It’s important that a wrapper class is used (ie java.lang.Integer, not int)
5 output property: the generated list of objects, for the calling test to grab
6 the mandatory execute(…​) API
7 the defaultParam(…​) (inherited from FixtureScript) will default the number property (using Java’s Reflection API) if none was specified
8 call another fixture script (SimpleObjectsTearDown) using the provided ExecutionContext. Note that although the fixture script is a view model, it’s fine to simply instantiate it (rather than using FactoryService#instantiate(…​)).
9 calling another fixture script (SimpleObjectCreate) using the provided ExecutionContext
10 adding the created object to the list, for the calling object to use.

Because this script has exposed a "number" property, it’s possible to set this from within the UI. For example:

prompt

When this is executed, the framework will parse the text and attempt to reflectively set the corresponding properties on the fixture result. So, in this case, when the fixture script is executed we actually get 6 objects created:

result list

It’s commonplace for one fixture script to call another. In the above example this script called SimpleObjectsTearDown and SimpleObjectCreate. Let’s take a quick look at SimpleObjectCreate:

public class SimpleObjectCreate extends FixtureScript {       (1)

    private String name;                                      (2)
    public String getName() { return name; }
    public SimpleObjectCreate setName(final String name) {
        this.name = name;
        return this;
    }
    private SimpleObject simpleObject;                        (3)
    public SimpleObject getSimpleObject() {
        return simpleObject;
    }
    @Override
    protected void execute(final ExecutionContext ec) {       (4)
        String name = checkParam("name", ec, String.class);   (5)
        this.simpleObject = wrap(simpleObjects)               (6)
                                .create(name);                (7)
        ec.addResult(this, simpleObject);                     (8)
    }
    @javax.inject.Inject
    private SimpleObjects simpleObjects;                      (9)
}
1 inherit from org.apache.isis.applib.fixturescripts.FixtureScript, as above
2 input property: name of the object; this time it is required
3 output property: the created simple object
4 the mandatory execute(…​) API
5 the checkParam(…​) (inherited from FixtureScript) will check that the "name" property has been populated (using Java’s Reflection API) and throw an exception if not
6 wrap the injected SimpleObjects domain service (using the WrapperFactory) to simulate interaction through the UI…​
7 .. and actually create the object using the "create" business action of that service
8 add the resulting object to the execution context; this makes the object available to access if run from the UI
9 inject the domain service into the fixture script

6.1.3. Using within Tests

Fixture scripts can be called from integration tests just the same way that fixture scripts can call one another.

For example, here’s an integration test from the SimpleApp archetype:

public class SimpleObjectIntegTest extends SimpleAppIntegTest {
    @Inject
    FixtureScripts fixtureScripts;                      (1)
    SimpleObject simpleObjectWrapped;
    @Before
    public void setUp() throws Exception {
        // given
        RecreateSimpleObjects fs =
             new RecreateSimpleObjects().setNumber(1);  (2)
        fixtureScripts.runFixtureScript(fs, null);      (3)

        SimpleObject simpleObjectPojo =
            fs.getSimpleObjects().get(0);               (4)
        assertThat(simpleObjectPojo).isNotNull();

        simpleObjectWrapped = wrap(simpleObjectPojo);   (5)
    }
    @Test
    public void accessible() throws Exception {
        // when
        final String name = simpleObjectWrapped.getName();
        // then
        assertThat(name).isEqualTo(fs.NAMES.get(0));
    }
    ...
}
1 inject the FixtureScripts domain service (just like any other domain service)
2 instantiate the fixture script for this test, and configure
3 execute the fixture script
4 obtain the object under test from the fixture
5 wrap the object (to simulate being interacted with through the UI)

6.1.4. Organizing Fixture scripts

There are lots of ways to organize fixture scripts, but we’ve used them as either:

These two styles are probably best illustrated with, well, some illustrations. Here’s a fixture script in the "flat" style for setting up a customer with some orders, a number of which has been placed:

flat 1

Notice how we have a single script that’s in control of the overall process, and takes responsibility for passing data from one fixture script to the next.

Here’s a similar, simpler script, from the same fictional app, to set up two customers:

flat 2

We can reuse the same fixture "customer" script, either calling it twice or (perhaps better) passing it an array of customer details to set up.

With the composite style, we rely on each fixture script to set up its own prerequisites. Thus:

composite

Back in the earlier section we noted the MultipleExecutionStrategy setting. We can now explain the meaning of this: the enum value of EXECUTE is designed for the flat style (where every fixture script will be called), whereas the enum value of IGNORE is designed for the composite style, and ensures that any fixture scripts visited more than once (eg TearDown) are only every executed the first time.

As already noted , the app generated by the SimpleApp archetype uses the flat structure, and we feel that it’s a better at separating out the "how" (how we set up some graph of domain objects into a known state, eg a customer with shipped placed orders and a newly placed order) from the "what" (what data should we actually use for the customer’s name, say).

The composite style tends to combine these, which one could argue does not separate responsibilities well enough. On the other hand, one could also make an argument that the composite style is a good way to implement precanned personas, eg "Joe", the customer who has a newly placed order, from "Mary" customer who has none.

Further approaches

As of there are two other approaches.

The first is to take advantage of a new MultipleExecutionStrategy, namely EXECUTE_ONCE_BY_VALUE. Under this strategy the determination as to whether to run a given fixture script is by comparing the fixture script against all others that have run. If all fixture scripts implement value semantics, then they can effectively determine whether they need to run or not.

This strategy was introduced in order to better support the ExcelFixture fixture script (provided by the (non-ASF) Incode Platform's excel module. The ExcelFixture takes an Excel spreadsheet and loads up each row. For those cases where we wish to ensure that the same spreadsheet is not loaded more than once, the IGNORE strategy would have required that a trivial subclass of ExcelFixture is created for each and every spreadsheet. The EXECUTE_ONCE_BY_VALUE on the other hand delegates the determination to the value semantics of the ExcelFixture, which is based on the contents of the spreadsheet.

Note that as of 1.10.0 the IGNORE enum has been deprecated, replaced by EXECUTE_ONCE_BY_CLASS

The second approach is in recognition that there is, in fact, something of a design flaw with the concept of MultipleExecutionStrategy: it requires that all fixture scripts being run follow the same conventions. There’s a good argument that this shouldn’t be a global "setting": the responsibility for determining whether a given fixture script should be executed should reside not in the FixtureScripts service but in the FixtureScript itself.

Thus, the FixtureScripts.ExecutionContext exposes the getPreviouslyExecuted() method that allows the fixture script to check for itself which fixture scripts have already been run, and act accordingly. For this approach, the MultipleExecutionStrategy should be left as simply EXECUTE.

6.2. SudoService

Sometimes in our fixture scripts we want to perform a business action running as a particular user. This might be for the usual reason - so that our fixtures accurately reflect the reality of the system with all business constraints enforced using the WrapperFactory - or more straightforwardly it might be simply that the action depends on the identity of the user invoking the action.

An example of the latter case is in the (non-ASF) Isis addons' todoapp's ToDoItem class:

Production code that depends on current user
public ToDoItem newToDo(
        @Parameter(regexPattern = "\\w[@&:\\-\\,\\.\\+ \\w]*") @ParameterLayout(named="Description")
        final String description,
        @ParameterLayout(named="Category")
        final Category category,
        @Parameter(optionality = Optionality.OPTIONAL) @ParameterLayout(named="Subcategory")
        final Subcategory subcategory,
        @Parameter(optionality = Optionality.OPTIONAL) @ParameterLayout(named="Due by")
        final LocalDate dueBy,
        @Parameter(optionality = Optionality.OPTIONAL) @ParameterLayout(named="Cost")
        final BigDecimal cost) {
    return newToDo(description, category, subcategory, currentUserName(), dueBy, cost);
}
private String currentUserName() {
    return container.getUser().getName(); (1)
}
1 is the current user.

The fixture for this can use the SudoService to run a block of code as a specified user:

Fixture Script
final String description = ...
final Category category = ...
final Subcategory subcategory = ...
final LocalDate dueBy = ...
final BigDecimal cost = ...
final Location location = ...

toDoItem = sudoService.sudo(username,
        new Callable<ToDoItem>() {
            @Override
            public ToDoItem call() {
                final ToDoItem toDoItem = wrap(toDoItems).newToDo(
                        description, category, subcategory, dueBy, cost);
                wrap(toDoItem).setLocation(location);
                return toDoItem;
            }
        });

Behind the scenes the SudoService simply talks to the DomainObjectContainer to override the user returned by the getUser() API. It is possible to override both users and roles.