This commit harmonizes dependencies used in smoke tests, in particular
by using the starters consistently. This serves not only as a validation
but also a showcase of how to use them.
Closes gh-47836
This commit modularizes spring-boot-test-autoconfigure. It now
contains only the code that's central to test auto-configuration.
Feature-specific functionality has moved out into -test modules,
some existing and some newly created. For example, `@DataJpaTest` can
now be found in spring-boot-data-jpa-test.
Closes gh-47322
Stéphane Nicoll
Moritz Halbritter
Andy Wilkinson
Hyunsang Han
Phillip Webb