A We shouldn't have an easy test like this one
B We shouldn't have an easy test as this one
C We shouldn't be given a test as easy as this one
Have a feeling that C ist the best alternative
What about A ...like... and B...as...?
That is my opinion too
You can also consider this:
We don't need a test as easy as that.
We don't need such an easy test.
We don't need a test like this. It's too easy.