ci: integrate the codecov

[qclc]

Add code coverage detection and ensure that 60%or higher of new code is covered with unit tests.

Currently we only focus on the coverage in the ./pkg directory, and will ignore the following packages or files in this directory:

• "pkg/apis"
• "pkg/client"
• "*_test.go"
• "fake_*.go"

[SOF3]

Does the coverage data here include packages without any test files? See golang/go#24570

I did a workaround in kelemetry because of this issue kubewharf/kelemetry@2647219

[qclc]

Does the coverage data here include packages without any test files? See golang/go#24570

I noticed this problem and it seems to be solved by adding the -coverpkg=./pkg/... parameter to the go test command.

When I experimented in my repository, it seemed that the coverage would include all packages in the ./pkg directory, even if there was no test file: qclc#2 (comment)

According to experimental results, the old test report will not cover packages that do not contain single tests(coverage of ./pkg is ~ 37%), but the new test report will cover all packages(coverage of ./pkg is ~ 24%), even if there are no unit tests in them.

Actually, I'm not sure why the above solution works, but it seems to solve the problem😂. Can you please help confirm if this solution meets expectations? @SOF3

[SOF3]

@qclc It seems the packages were included simply because your PR had diff in those packages. Maybe try with another commit that does not involve those packages? Would the total coverage decrease again?

[qclc]

@qclc It seems the packages were included simply because your PR had diff in those packages. Maybe try with another commit that does not involve those packages? Would the total coverage decrease again?

@SOF3 I experimented again and only modified the package containing the unit test. The coverage remained unchanged, which was also ~24% : https://app.codecov.io/gh/qclc/kubeadmiral/pull/4 . I also ran go test locally and observed the test report. After adding the -coverpkg=./pkg/... parameter, the test report will include all the packages in the ./pkg directory. Otherwise, it won't. It seems that the test report after adding the -coverpkg=./pkg/... parameter is fully covered.

[codecov-commenter]

Welcome to Codecov 🎉

Once merged to your default branch, Codecov will compare your coverage reports and display the results in this comment.

Thanks for integrating Codecov - We've got you covered ☂️

[qclc]

Sorry to miss this comment on issue (golang/go#24570 (comment)) : using -coverpkg does not actually help if the package is never called in any test at all. -coverpkg is a cover-up that allows packages from a different package to provide coverage for this package.

The end result still requires some additional work to ensure coverage is reported for every package, as @SOF3 did in repository kelemetry. Please take a review.