There should be sniffs that encourage using the most specific assertion that is available.
I've created some tasks to update current uses, but for new code
T244279: assertNull should be used instead of comparing to null: assertSame( null, ... ) should be assertNull( ... )
T244552: assertTrue should be used instead of comparing to true: assertSame( true, ... ) should be assertTrue( ... )
T244553: assertFalse should be used instead of comparing to false: assertSame( false, ... ) should be assertFalse( ... )
T244554: assert(Greater|Less)Than(OrEqual)? should be used instead of assert(True|False):
- assertTrue( a > b ) should be assertGreaterThan( b, a )
- assertTrue( a >= b ) should be assertGreaterThanOrEqual( b, a )
- assertTrue( a < b ) should be assertLessThan( b, a )
- assertTrue( a <= b ) should be assertLessThanOrEqual( b, a )