aae5cdf1aa
Code coverage requires `lcov`, so update the docs to call it out specifically. Signed-off-by: Paul Fagerburg <pfagerburg@google.com> Change-Id: Ie2898faa5188a7174c4e56ba34f1a4f02f939b03 Reviewed-on: https://review.coreboot.org/c/coreboot/+/58633 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Martin Roth <martinroth@google.com>
60 lines
2.4 KiB
Markdown
60 lines
2.4 KiB
Markdown
# Unit Test Code Coverage
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Code coverage for the coreboot unit tests allows us to see what lines of
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code in the coreboot library are covered by unit tests, and allows a test
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author to see where they need to add test cases for additional coverage.
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Code coverage requires `lcov`; install the tool if necessary by
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`sudo apt install lcov` or the equivalent for your system.
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Enable code coverage in your unit test build by setting the environment
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variable `COV` to 1; either `export COV=1` in your shell, or add it to your
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`make` command, e.g. `COV=1 make unit-tests`.
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The build output directory is either `build/tests` or `build/coverage`,
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depending on whether `COV=1` is set in the environment.
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All of the unit test targets are available with and without `COV=1`
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* `clean-unit-tests`
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* `build-unit-tests`
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* `run-unit-tests`
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* `unit-tests` (which is just `build-unit-tests` followed by `run-unit-tests`)
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There are two new `make` targets:
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* `coverage-report` generates a code coverage report from all of the
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GCOV data (`*.gcda` and `*.gcno` files) in the build directory. To view the
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coverage report, open `build/coverage/coverage_reports/index.html` in your web
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browser.
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* `clean-coverage-report` deletes just the coverage report.
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The `coverage-report` and `clean-coverage-report` targets automatically set
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`COV=1` if it is not already set in the environment.
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## Examples
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`COV=1 make unit-tests coverage-report` builds all of the unit tests with code
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coverage, runs the unit tests, and generates the code coverage report.
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`COV=1 make build-unit-tests` builds all of the unit tests with code coverage.
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`COV=1 make run-unit-tests` runs the unit tests, building them with code
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coverage if they are out-of-date.
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`COV=1 make coverage-report` creates the code coverage report. This
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target does not explicitly depend on the tests being built and run; it gathers
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the code coverage data from the output directory, which it assumes already
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exists.
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`COV=1 make tests/lib/uuid-test coverage-report` builds the uuid test
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with code coverage, runs it, and generates a code coverage report just for
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that test.
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As a demonstration that building with and without coverage uses different
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output directories:
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1. `make build-unit-tests` builds unit tests without code coverage into
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`build/tests`.
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2. `COV=1 make clean-unit-tests` cleans `build/coverage`
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3. `make build-unit-tests` doesn't need to build anything in `build/tests`,
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because those files weren't affected by the previous `clean-unit-tests`.
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