ICC has taken back test status from Zimbabwe because of political reasons but haven't done that with Bangladesh despite there poor test performance for years. But in this series Bangladesh has chance not because Bangladesh test performance has enhanced but due to fact that Srilanka performance has dropped so low.
Zimbabwe is having the test status right now, but they are relegated to the second division along with Ireland and Afghanistan. It is a very meaningless division, as these teams almost never play any test matches. Do you guys remember the last time when Ireland and Afghanistan played test format? What is the point in giving these countries test status, if the other full members refuse to play against them? Not that I am a big fan of test cricket, but these teams deserve at least 2-3 matches per year against teams such as India and Australia.