Merging Coverage Data

You can merge coverage data from multiple runs with -a/--add-tracefile.

For each run, generate JSON output:

...  # compile and run first test case
gcovr ... --json run-1.json
...  # compile and run second test case
gcovr ... --json run-2.json

Next, merge the json files and generate the desired report:

gcovr --add-tracefile run-1.json --add-tracefile run-2.json --html-details coverage.html

You can also use unix style wildcards to merge the json files without duplicating -a/--add-tracefile. With this option you have to place your pathnames with wildcards in double quotation marks:

gcovr --add-tracefile "run-*.json" --html-details coverage.html