There is more than just “Line Code Coverage”...
Here is a great description of different forms of code coverage. Thanks to Florian for the recap!!
Statement Coverage:
how many portions of the CFG are executed (nodes & edges)
#executed / #total
-> still possible to miss bugs
Branch Coverage:
test all possible branches in control flow (edges)
complete branch coverage implies complete statement coverage
-> still possible to miss bugs
Path Coverage:
test all possible paths (sequence of branches)
complete path coverage implies complete branch coverage
-> not feasible with loops (arbitrary # of paths)
Loop Coverage:
for each loop, test 0, 1, and 1+ iterations
coverage = #loops with 0,1,1+ iterations / #loops * 3s
Data Flow Coverage:
evaluated with DU pairs
coverage = #DU-pairs / used DU-pairs
Glossary
CFG = control-flow graph
nodes with statements immediately and always executed after each other
nodes are connected by edges if reachable
for example, an if condition statement produces three nodes A (statements before if), B (statements if condition true),C (statements if condition false) and edges between A->B and A->C
DU: definition use pair
defines where variable used at the moment was defined at; each variable has typically many definition use pairs
for example, (2,3) means the variable a used at line 3 was assigned to (hence defined) at line 2
All the details here: https://www.pm.inf.ethz.ch/education/courses/software-engineering-and-architecture.html See the Download Section if the PDF Download Link ist broken https://ethz.ch/content/dam/ethz/special-interest/infk/chair-program-method/pm/documents/Education/Courses/SS2018/SAE/05%20-%20testing.pdf