The previous support required the JUnit Jupiter engine on the classpath. This further clarifies the default support for JUnit 4 to require an extra dependency within projects that require it, while the default support will be JUnit 5.
It was odd to me that brand new projects require an exclusion from spring-boot-starter-test to kick off the default support for JUnit 5. Since it is as simple as adding a user dependency to the vintage engine, why not go with that?
Comment From: wilkinsona
Thanks for the suggestion, but the starter needs to work for Gradle users and for Maven users who are not using spring-boot-starter-parent.