MC/DC testing requires focusing test cases on each condition individually to cover all possible outcomes of that condition, which can be done with fewer test cases than full pairwise testing. It works by fixing all other conditions while toggling the focused condition, resulting in test cases that ensure each condition alone can correctly affect the final decision. When all individual condition test cases are combined, the total number of test cases is less than that required for pairwise testing, providing coverage with fewer tests.

1. MC/DC (Modified Condition / Decision Coverage)
A B C Final decision (Pattern)
Focusing on Cond. A: Fix B and C
TRUE TRUE TRUE TRUE (1)
FALSE TRUE TRUE FALSE (2)
Focusing on Cond. B: Fix A and C
TRUE TRUE TRUE TRUE (1)
TRUE FALSE TRUE FALSE (3)
Focusing on Cond. C: Fix A and B
TRUE TRUE TRUE TRUE (1)
TRUE TRUE FALSE FALSE (4)
Cond. A && Cond. B && Cond. C
Statement X
FALSE
TRUE
MC/DC confirms :
- Each condition can affect the final decision correctly
with less test case than C2
A B C (Pattern)
TRUE TRUE TRUE (1)
FALSE TRUE TRUE (2)
TRUE FALSE TRUE (3)
TRUE TRUE FALSE (4)
Test case design :
Focus on each condition so as to make the final decision by only itself
Combined test case :
Less than C2
50% decreased from C2
(C2 : all condition combinations
= 23 = 8 test cases)