Code Coverage #

Categories of coverage #

• executed - this line of code was hit during execution
• instrumented - this line of code was part of the compilation unit, but not executed
• missing - in a source file, but not compiled.
• ignored - not an executable line, or a line we don't care about

Coverage is calculated as exe / (inst + miss). In general, lines that are in miss should be ignored, but our exclusion rules are not good enough.

Buildbots #

Buildbots are currently on the experimental waterfall. The coverage figures they calculate come from running some subset of the chromium testing suite.

• Linux)
  • uses gcov
• Windows
• Mac

Also,

• Coverage dashboard
• Example coverage summary
  • the coverage is calculated at directory and file level, and the directory structure is navigable via the Subdirectories table.

Calculating coverage locally #

TODO

Advanced Tips #

Sometimes a line of code should never be reached (e.g., NOTREACHED()). These can be marked in the source with // COV_NF_LINE. Note that this syntax is exact.