Doc/feat Transaction Template tests

[xenoterracide]

So recently I had problems testing something that would have been easy to do with TransactionTemplate, that something was envers and it's documented in the spring data envers docs, which I didn't completely read, and that's my fault. However, doing this with spring boot is a little different because it can set the test up for you. However, it's perhaps not as streamlined as DataJpaTest. This is what came up with

@SpringBootTest
@AutoConfigureDataJpa
@AutoConfigureTestDatabase
public class JpaAggregateTest {

  @Autowired
  TransactionTemplate tx;
  
  @Autowired
  FooAggregateRepository repository;

I'm not even sure if that's all necessary, but it works.

However I was thinking at minimum it might be nice to document in the reference docs. The javadoc for @AutoconfigureDataJpa also suggests I shouldn't be using it, it might be better to update that to "when" I should be using it.

I'm thinking that it might be convenient to add @DataTransactionTemplateTest and @JdbcTransactionTemplateTest, but that might be overkill when documentation would suffice. However, if those were to exist they could possibly go the next mile and set up a different h2 database that would get destroyed either at the end of the test or at least after class, instead of perpetuating for the whole suite (which I believe it does now).

[philwebb]

Thanks for the suggestion, but I think it might be hard for us to describe this scenario in the @AutoconfigureDataJpa javadoc.

The "Most tests should consider using ... rather than using this annotation directly" is standard text that we put on many @Autoconfigure... annotations. We're basically trying to say that you should use usually the @...Test annotation, but the @Autoconfigure... annotations are here if you need more fine-grained control.

I'm afraid that adding a @DataTransactionTemplateTest feels a bit too specific as well. I think we need to hit the sweet spot of offering useful annotations without having too many of them. You could probably add this annotation to your own code and meta-annotate it with the subset of @AutoconfigureDataJpa annotations that you need.