fill gaps in test conditions

[briskt]

Fixes Or Enhances

Added some corner cases to tests to improve test coverage, but also to gain understanding of the code.

Make sure that you've checked the boxes below before you submit PR:

• Tests exist or have been written that cover this particular change.

@go-playground/validator-maintainers

[coveralls]

coverage: 74.464% (+0.1%) from 74.318%
when pulling 828515f on briskt:master
into 6c3307e on go-playground:master.

[briskt]

closing because it doesn't provide any value but makes the code longer