gocicov

gocicov is a tool for generating go code coverage inside a CI pipeline. It runs the tests, writing the test output and a code coverage summary to standard error. It then returns an integer value for the total code coverage to standard output which may be used to track code coverage. This integer is the total code coverage in hundredths of a percent.

Unlike normal code coverage with go test the total percentage includes packages for which no test files exist.

gocicov uses a pair of environment variables to enforce changes in code coverage. COVERAGE is the existing coverage in hundredths of a percent. COVERAGE_THRESHOLD is the maximum permissable drop in code coverage, also in hundredths of a percent.

gocicov fails if any of the tests fail or if the tests pass but the coverage threshold is not met.

Example usage

$ newcoverage=$(COVERAGE=100 COVERAGE_THRESHOLD=200 gocicov)
WARNING: tests needed for cmd/gocicov
WARNING: tests needed for internal/coverage
WARNING: tests needed for internal/forcetest
testing: warning: no tests to run
PASS
coverage: 0.0% of statements in ./...
ok  	github.com/moltin/gocicov/cmd/gocicov	0.180s	coverage: 0.0% of statements in ./... [no tests to run]
testing: warning: no tests to run
PASS
coverage: 0.0% of statements in ./...
ok  	github.com/moltin/gocicov/internal/coverage	0.484s	coverage: 0.0% of statements in ./... [no tests to run]
testing: warning: no tests to run
PASS
coverage: 0.0% of statements in ./...
ok  	github.com/moltin/gocicov/internal/forcetest	0.323s	coverage: 0.0% of statements in ./... [no tests to run]
Total coverage: 0.00%
Coverage diff: -1.00%
$ echo $newcoverage
0

Example buddy action

Having set up project-level variables COVERAGE (should be settable) and COVERAGE_THRESHOLD:

  actions:
    - action: "Unit Tests and Linting"
      type: "BUILD"
      docker_image_name: "library/golang"
      docker_image_tag: "1.14-stretch"
      setup_commands:
        - "go get -u github.com/moltin/gocicov/cmd/gocicov"
      execute_commands:
        - "newcoverage=$(gocicov)"
        - "if [ $BUDDY_EXECUTION_BRANCH = master ]; then COVERAGE=$newcoverage ; fi"

Skipping coverage

It is possible to skip coverage of specific packages where code coverage makes no sense (like generated code). A file called .coverageignore can contain a list of import paths to ignore. For example:

./cmd/app
./external/...

Note that skipping coverage also skips performing tests for affected modules.