Testing Aggreate Creation Command using GivenWhenThenFixture

Imported from Google Groups
1

Hi All,

When testing simple aggreate creation command I always encounter the following error:

java.lang.AssertionError: The aggregate used in this fixture was initialized with an identifier different than the one used to load it. Loaded [0], but actual identifier is [10000].
Make sure the identifier passed in the Command matches that of the given Events.
at org.axonframework.test.GivenWhenThenTestFixture$IdentifierValidatingRepository.validateIdentifier(GivenWhenThenTestFixture.java:435)
at org.axonframework.test.GivenWhenThenTestFixture$IdentifierValidatingRepository.load(GivenWhenThenTestFixture.java:429)
at org.axonframework.test.GivenWhenThenTestFixture$IdentifierValidatingRepository.load(GivenWhenThenTestFixture.java:411)
at org.axonframework.test.GivenWhenThenTestFixture.detectIllegalStateChanges(GivenWhenThenTestFixture.java:271)
at org.axonframework.test.GivenWhenThenTestFixture.when(GivenWhenThenTestFixture.java:236)
at org.axonframework.test.GivenWhenThenTestFixture.when(GivenWhenThenTestFixture.java:223)

…

I can get rid of above error by invoking FixtureConfiguration#setReportIllegalStateChange(false) but it seems wrong to do so since my aggregate is simple.

Below is the test code:
`
fixture.givenNoPriorActivity().when(new CreateEmployeeCommand(name, contact, joinedDate))
.expectVoidReturnType()
.expectEvents(new EmployeeCreatedEvent(10000, name,contact, joinedDate));

`

And below is the Aggregate:
`
class Employee extends AbstractAnnotatedAggregateRoot
{
private static final long serialVersionUID = 7125543543552936997L;
private final LongIdentifierGenerator GENERATOR = new LongGenerator(false, 10000);

@AggregateIdentifier
private long id;

@CommandHandler
public Employee(CreateEmployeeCommand command)
{
apply(new EmployeeCreatedEvent(GENERATOR.nextLongIdentifier(), command.getName(), command.getContact(), command.getJoinDate()));
}

@EventSourcingHandler
private void handleEmployeeCreatedEvent(EmployeeCreatedEvent event)
{
this.id = event.getId();
}
}

`

Any help would be greatly appreciated.

Thanks & Regards,
Setya

2

Hi,

I don’t have the means to check this right now, but I think the problem may be related to the ‘long’ identifier. Try changing it to a Long (object type). Since the primitive has no null value, Axon may falsely assume the identifier is initialized at 0.

Cheers,

Allard

3

Hi Allard,

Thank you. Changing into Long solves the problem. But then I’ve got 2nd error caused by expectVoidReturnType() :

The command handler returned an unexpected value.

Expected but got <10000>

Regards,

Setya

4

Hi Setia,

by default, the constructor command handler returns the id of the newly created aggregate. That’s why you get the 10000.

Cheers,

Allard

5

Hi Allard,

So for aggregate creation command I should always expect the generated id as return value instead of void?

Thanks & Regards,
Setya

6

Yes. Or just don’t validate the return value at all, unless you’re intending to rely on it.

7

Hi Allard,

Thanks for your help.

Regards,

Setya