I'm sorry your question is too vague. You want to test how much battery you have left? How long the battery will last during the life of the phone? How much you can do with the charge you have left? How to drain the battery so you can see what drains it fastest? An app that measures battery????
did a test (power saving mode was off) and got 94%
the test says that it's suppose to be 70%, anyway i see no problem...
tested with a normal use and it lasted about 30 hours.