I do not think that God is sitting up there waiting for ways to make us miserable just to see if we will continue to trust. However, life does bring with it a series of testings and opportunities to continue to believe. Life just happens, and so do bad things. It's not that God prevents everything bad from happening so that we have a nice cushy stay on earth...it's just that He works in the midst of them.
1 Thessalonians 2:13b says that His word performs its work in you who believe. The only stipulation here, if there is one, is that we believe. God's word does not stop carrying us because we hit tough times or things in life did not work out like we thought they were supposed to. His word continues to work as we believe. That's not an empty promise of healing, prosperity or cheap peace...the security here is that His Word is not bound by our circumstances. He is working in us in the midst of the circumstances. We must simply believe that He is...and come to Him. Even in our broken state, in our worrisome state, in our painful state...just come. He will not cast us away - He is still at work in us.