From de6cbac3c4e44de797bc2a4755fb765cf5a49f55 Mon Sep 17 00:00:00 2001 From: Paul Fagerburg Date: Tue, 11 May 2021 09:56:48 -0600 Subject: tests: improve code coverage support Fix the exclusion path for lcov; it should exclude the directory with source code, not object files. Use the COV environment variable to * control whether we build for coverage or not * select the output directory Add a separate target for generating the report, so we can get a report for all of the tests together or just a single test. Add documentation. Signed-off-by: Paul Fagerburg Change-Id: I2bd2bfdedfab291aabeaa968c10b17e9b61c9c0a Reviewed-on: https://review.coreboot.org/c/coreboot/+/54072 Tested-by: build bot (Jenkins) Reviewed-by: Jakub Czapiga --- Documentation/technotes/2021-05-code-coverage.md | 56 ++++++++++++++++++++++++ 1 file changed, 56 insertions(+) create mode 100644 Documentation/technotes/2021-05-code-coverage.md (limited to 'Documentation/technotes') diff --git a/Documentation/technotes/2021-05-code-coverage.md b/Documentation/technotes/2021-05-code-coverage.md new file mode 100644 index 0000000000..ec7f4cb5f9 --- /dev/null +++ b/Documentation/technotes/2021-05-code-coverage.md @@ -0,0 +1,56 @@ +# Unit Test Code Coverage + +Code coverage for the coreboot unit tests allows us to see what lines of +code in the coreboot library are covered by unit tests, and allows a test +author to see where they need to add test cases for additional coverage. + +Enable code coverage in your unit test build by setting the environment +variable `COV` to 1; either `export COV=1` in your shell, or add it to your +`make` command, e.g. `COV=1 make unit-tests`. + +The build output directory is either `build/tests` or `build/coverage`, +depending on whether `COV=1` is set in the environment. + +All of the unit test targets are available with and without `COV=1` +* `clean-unit-tests` +* `build-unit-tests` +* `run-unit-tests` +* `unit-tests` (which is just `build-unit-tests` followed by `run-unit-tests`) + +There are two new `make` targets: +* `coverage-report` generates a code coverage report from all of the +GCOV data (`*.gcda` and `*.gcno` files) in the build directory. To view the +coverage report, open `build/coverage/coverage_reports/index.html` in your web +browser. +* `clean-coverage-report` deletes just the coverage report. + +The `coverage-report` and `clean-coverage-report` targets automatically set +`COV=1` if it is not already set in the environment. + + +## Examples + +`COV=1 make unit-tests coverage-report` builds all of the unit tests with code +coverage, runs the unit tests, and generates the code coverage report. + +`COV=1 make build-unit-tests` builds all of the unit tests with code coverage. + +`COV=1 make run-unit-tests` runs the unit tests, building them with code +coverage if they are out-of-date. + +`COV=1 make coverage-report` creates the code coverage report. This +target does not explicitly depend on the tests being built and run; it gathers +the code coverage data from the output directory, which it assumes already +exists. + +`COV=1 make tests/lib/uuid-test coverage-report` builds the uuid test +with code coverage, runs it, and generates a code coverage report just for +that test. + +As a demonstration that building with and without coverage uses different +output directories: +1. `make build-unit-tests` builds unit tests without code coverage into +`build/tests`. +2. `COV=1 make clean-unit-tests` cleans `build/coverage` +3. `make build-unit-tests` doesn't need to build anything in `build/tests`, +because those files weren't affected by the previous `clean-unit-tests`. -- cgit v1.2.3