Why in life you are always tested and challenged when God wants to make us happy?
Know that every test in an opportunity for you to grow. Don't take it as a test!
A test is not to know whether you are strong or not, but it for you to realize that 'Yes, I am strong'. God is not ignorant that he needs to check and see whether you have the strength or not. God already knows your capacity; nature knows your capacity. The tests are for you to realize that you are strong.
If you find that you are going through testing times, it is for you to realize that you are much bigger and you can overcome that. It is for your own knowledge.