Given the following fragment of code, how many tests are required for 100% decision coverage? discount = 0 order_quantity=0 real order_quantity if order_quantity >=20 then discount = 0.05 if…

Question

Options

• A
• B
• C
• D

• A
  71% (37)
• B
  4% (2)
• C
  8% (4)
• D
  17% (9)

Explanation

Option A (3 tests) is correct because the code contains 2 decisions (the outer if order_quantity >= 20 and the inner if order_quantity >= 100), and decision coverage requires each decision to evaluate to both TRUE and FALSE. The three test cases needed are: (1) order_quantity < 20 - outer decision FALSE, inner never reached; (2) 20 ≤ order_quantity < 100 - outer TRUE, inner FALSE; (3) order_quantity ≥ 100 - both TRUE.

Option D (2) is wrong because two tests cannot cover all four decision outcomes - you'd have to leave at least one branch unexercised. Options B (4) and C (5) are wrong because they overcount; once both decisions have been driven TRUE and FALSE, coverage is complete with no additional tests needed.

Memory tip: For nested if statements, count the decisions and remember that a FALSE on the outer if "skips" the inner one entirely - so you don't need a separate test for the inner FALSE independently of the outer TRUE. That nesting is what keeps it at 3, not 4.

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