Why do we use test coverage?
- Coverage provides a quantitative measurement of how well we have validated the code
Let's consider the following piece of code where test case is n=10
public boolean isTen(int n) {
if (n == 10) {
return true;
}
return false;
}Instruction Coverage
- how many instructions are covered
- a single line of code may be compiled to one or multiple bytecode instructions
Branch Coverage
- how many branches of the control structures (if, switch, etc) have been executed
- for this case, the false block is not covered, so the coverage is 1/2 = 50%
Line Coverage
- also known as statement coverage
- counts the number of lines (statements) executed
- If the input is n = 10, the fourth statement return false; is not ran, so the coverage is 3/4 = 75%
Method Coverage
- counts the number of methods executed
- for this case we only have one method, so the coverage is 1/1 = 100%