Below are some notes on how to use the 'gcov' and 'lcov' test coverage programs.

'gcov' is easy to use, however it produces lots of files even for a simple program.

• Add the following options to your compile and linker commands '-fprofile-arcs -ftest-coverage'
  • g++ -O0 -g3 -Wall -c -fprofile-arcs -ftest-coverage -o main.o ./main.cpp
  • g++ -fprofile-arcs -ftest-coverage -o avltree ./main.o
• After building main.cpp you will see the below file created:
  • main.gcno
• After running your recompiled executable files like below will be created:
  • main.gcda
• Now produce your coverage results
  • gcov main.cpp

  • 		File '../main.cpp'
    		Lines executed:76.00% of 250
    		../main.cpp:creating 'main.cpp.gcov'
    
    		...
    
    		File '../avltree.h'
    		Lines executed:89.41% of 236
    		../avltree.h:creating 'avltree.h.gcov'
    
    		...
    
    		File '../treenode.h'
    		Lines executed:100.00% of 45
    		../treenode.h:creating 'treenode.h.gcov'
    
    		...
    		

• Now view the coverage report
  • more avltree.h.gcov

  • 			...
    			...
    		        -:  206:template
    		  3091570:  207:treenode * avltree::rotateLeft(treenode * subtree) {
    		  3091570:  208:	treenode * pivot = NULL;
    		        -:  209:
    		  3091570:  210:	pivot = subtree->getRight();
    		  3091570:  211:	subtree->setRight(pivot->getLeft());
    		  3091570:  212:	pivot->setLeft(subtree);
    		        -:  213:
    		  3091570:  214:	subtree->updateHeight();
    		  3091570:  215:	pivot->updateHeight();
    		        -:  216:
    		  3091570:  217:	return pivot;
    		        -:  218:}
    		        -:  219:
    			...
    			...
    		

lcov

'lcov' is a graphical front end for 'gcov' that produces a great html summary of your test coverage.



Along with the summary a report of exercised lines of code (blue), and untested code (orange) is produced.



An example run of 'lcov' is below.

• Initialize the directory where you wish to store the 'html' result in:
  • mkdir lcovdir
  • cd lcovdir
  • lcov --directory ../ --zerocounters
• Run the test application:
  • ../avltree
• Process the results into a single file:
  • lcov --directory ../ --capture --output-file app.info
• Generate the html results and view them
  • genhtml -o . app.info
  • firefox ./index.html