[java] Merge Junit assertion simplification rules #2908
Description
The following rules:
- bestpractices.xml
- UseAssertEqualsInsteadOfAssertTrue
- UseAssertNullInsteadOfAssertTrue
- UseAssertSameInsteadOfAssertTrue
- UseAssertTrueInsteadOfAssertEquals
- design.xml/SimplifyBooleanAssertion
could be merged together into a new SimplifiableTestAssertion rule. This would
- make them simpler to reference, you probably want all of them, and SimplifyBooleanAssertion is alone in design.xml
- simplify the implementation (currently some logic is duplicated between rules)
Category would likely be bestpractices.xml
Motivation for the rule would be readability + better error messages
Additional context
#2899 reimplements many of those, but not SimplifyBooleanAssertion. We can merge them later