Additional instances (IF OR AND) Help Please

I am struggling to write a 2 part formula in Column D of this sheet AND/IF/OR Sheet Link

The requirement is to look for "test1 or "test2" in Column A, If either are found, show 0 in column D.

If they are not then apply Part 2 which looks for the value in column B, if the number is greater than 1, then subtract 1 from the entry and thus showing the additional instances based on the text in column A

Realising my description may not be the best .. J. i have tried again below

Alternatively, if you have a more efficient method, it would be greatly appreciated.

Part1 Criteria A2 = test1 or test2

Value if True 0

Value if False Part 2

Part 2 Criteria B2 is greater than 1

Value if True B2-1*C2

Value if False 0

=IF(B2>1,B2-1*C2)