1# Unit Test Code Coverage 2 3Code coverage for the coreboot unit tests allows us to see what lines of 4code in the coreboot library are covered by unit tests, and allows a test 5author to see where they need to add test cases for additional coverage. 6 7Code coverage requires `lcov`; install the tool if necessary by 8`sudo apt install lcov` or the equivalent for your system. 9 10Enable code coverage in your unit test build by setting the environment 11variable `COV` to 1; either `export COV=1` in your shell, or add it to your 12`make` command, e.g. `COV=1 make unit-tests`. 13 14The build output directory is either `build/tests` or `build/coverage`, 15depending on whether `COV=1` is set in the environment. 16 17All of the unit test targets are available with and without `COV=1` 18* `clean-unit-tests` 19* `build-unit-tests` 20* `run-unit-tests` 21* `unit-tests` (which is just `build-unit-tests` followed by `run-unit-tests`) 22 23There are two new `make` targets: 24* `coverage-report` generates a code coverage report from all of the 25GCOV data (`*.gcda` and `*.gcno` files) in the build directory. To view the 26coverage report, open `build/coverage/coverage_reports/index.html` in your web 27browser. 28* `clean-coverage-report` deletes just the coverage report. 29 30The `coverage-report` and `clean-coverage-report` targets automatically set 31`COV=1` if it is not already set in the environment. 32 33 34## Examples 35 36`COV=1 make unit-tests coverage-report` builds all of the unit tests with code 37coverage, runs the unit tests, and generates the code coverage report. 38 39`COV=1 make build-unit-tests` builds all of the unit tests with code coverage. 40 41`COV=1 make run-unit-tests` runs the unit tests, building them with code 42coverage if they are out-of-date. 43 44`COV=1 make coverage-report` creates the code coverage report. This 45target does not explicitly depend on the tests being built and run; it gathers 46the code coverage data from the output directory, which it assumes already 47exists. 48 49`COV=1 make tests/lib/uuid-test coverage-report` builds the uuid test 50with code coverage, runs it, and generates a code coverage report just for 51that test. 52 53As a demonstration that building with and without coverage uses different 54output directories: 551. `make build-unit-tests` builds unit tests without code coverage into 56`build/tests`. 572. `COV=1 make clean-unit-tests` cleans `build/coverage` 583. `make build-unit-tests` doesn't need to build anything in `build/tests`, 59because those files weren't affected by the previous `clean-unit-tests`. 60