The error message produced by isEqualTo prints out the class name when the values have the same representation. While this helps disambiguate types with different class names, it doesn't help when the two types have the same name but different packages.

For example, assuming two enum types, both having a VALUE constant:

• org.example.pkg1.Enum1
• org.example.pkg2.Enum1

the following:

assertThat(org.example.pkg1.Enum1.VALUE).isEqualTo(org.example.pkg2.Enum1.VALUE);

yields:

org.opentest4j.AssertionFailedError: 
expected: "VALUE (Enum1@d6da883)"
 but was: "VALUE (Enum1@5cdd8682)"

In such cases, printing the fully qualified class name would make the message clearer:

org.opentest4j.AssertionFailedError: 
expected: "VALUE (org.example.pkg1.Enum1@d6da883)"
 but was: "VALUE (org.example.pkg2.Enum1@5cdd8682)"

Any assertion that uses UnambiguousRepresentation which relies on Representation::unambiguousToStringOf could benefit from this improvement, including the recursive comparison.