gcov indicates this, since there are branches that are still, never executed.
gcov indicates this, since there are branches that are still, never executed
(branch 3). For example, `a = 1` masks the condition `b == 0` in the decision
For example, `a = 1` masks the condition `b == 0` in the decision `(a > 1 && b == 0)`
`(a > 1 && b == 0)` because it makes the condition `a > 1` false and therefore
because it makes the condition `a > 1` false and therefore the executable
the executable doesn't need to evaluate the other condition (`b == 0`) to
doesn't need to evaluate the other condition to determine the outcome of the
determine the outcome of the AND expression. These are the 'short-circuit'
AND expression. These are the 'short-circuit' semantics of the C language.
semantics of the C language.
Hence, we need to modify the test cases to ensure the coverage of masking
Hence, we need to modify the test cases to ensure the coverage of masking
conditions, and that's called modified condition decision coverage (MCDC):
conditions, and that's called modified condition decision coverage (MCDC):
...
@@ -182,4 +182,7 @@ as executed by gcov:
...
@@ -182,4 +182,7 @@ as executed by gcov:
branch 2 taken 1 (fallthrough)
branch 2 taken 1 (fallthrough)
branch 3 taken 1
branch 3 taken 1
Put plainly, there are no "0" counters in any lines or branches; i.e. 100%
statement and branch coverage.
*The content above is based on [a nice (but slightly buggy) Quora article](https://www.quora.com/What-is-the-difference-between-decision-coverage-and-condition-coverage-when-it-comes-to-code-coverage).*
*The content above is based on [a nice (but slightly buggy) Quora article](https://www.quora.com/What-is-the-difference-between-decision-coverage-and-condition-coverage-when-it-comes-to-code-coverage).*
