Please provide a proper reproducible bug report. Don't make us GUESS what function you are referring to.

I don't know any "splitextTest" function that you describe in the bug report title. Do you mean os.path.splitext? Then you should say so. If not, then what function are you referring to?

What results do you expect, why do you expect them, and what results do you get?

Why should we care what test results some Java library returns? Maybe they've got it wrong, or maybe their function just works differently from ours. Unless this function is documented as being exactly compatible with the Java code you link to, I don't think it is very important what guava does.

Perhaps you should raise a bug report at Guava and tell them that according to the Python language, their function is wrong.

The os.path.splitext function is documented as returning the file extension as either the empty string "" or beginning with a single period, and leading dots are not part of the extension. So the examples you show are correct, if you are talking about os.path.splitext. If you are talking about something else, please explain what.

https://docs.python.org/3/library/os.path.html#os.path.splitext