You have already known plenty of Russian phrases!
Everybody uses idioms in his/her speech. They make sentences more emotional, beautiful and interesting. Each country has its own special proverbs and sometimes they can be very difficult for other people.
Knowing idioms of other countries is very important if you want to broaden your horizon. If you know different unique phrases, you can understand foreigners or even teach other people.
Passing this test, you will learn some Russian idioms with using your knowledge and logic. In this way you can check also your linguistic skills and intuition.
Try to answer honestly, without using the Internet. Then you can get correct results.