action: update workflow to block low unit test coverage code

[adamqqqplay]

In order to improve the code quality of this project, we have introduced a test coverage check in CI to prevent code with low unit test coverage from being merged. Although there is no perfect code coverage value, we can still make a stab at such a value. 3 years ago, Google posted a blog post on their best practices:

We offer the general guidelines of 60% as “acceptable”, 75% as “commendable” and 90% as “exemplary.”

Therefore, in order to increase the overall code coverage of this project to 60% mentioned in #334, we set the coverage of each patch to 75% and above.

Patch details:

1. The project's unit test coverage cannot be reduced by more than 0.5%.
2. The unit test coverage of each patch must be higher than 75%.

Reference: https://about.codecov.io/blog/the-case-against-100-code-coverage/

[codecov-commenter]

Codecov Report

Merging #460 (689c25c) into main (f89d069) will not change coverage.
The diff coverage is n/a.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #460   +/-   ##
=======================================
  Coverage   37.13%   37.13%           
=======================================
  Files          60       60           
  Lines        6912     6912           
=======================================
  Hits         2567     2567           
  Misses       4048     4048           
  Partials      297      297           

[imeoer]

Maybe add a blank line here, others LGTM.

[adamqqqplay]

Fixed.

[adamqqqplay]

Smoke tests usually fail and may need to be re-run.

[changweige]

@imeoer Should we bump the nydus-image for Converter UT tests?

time="2023-04-28T03:24:51Z" level=info module=builder
time="2023-04-28T03:24:51Z" level=info msg="USAGE:" module=builder
time="2023-04-28T03:24:51Z" level=info msg=" nydus-image unpack --bootstrap --log-level --output " module=builder
time="2023-04-28T03:24:51Z" level=info module=builder
time="2023-04-28T03:24:51Z" level=info msg="For more information try --help" module=builder
time="2023-04-28T03:24:51Z" level=error msg="fail to run /usr/bin/nydus-image [unpack --log-level warn --bootstrap /tmp/nydus-converter-1649642338/image.boot --output /tmp/nydus-converter-1649642338/oci.tar --backend-config /tmp/nydus-converter-1649642338/backend-config.json]" error="exit status 1"
converter_test.go:303:
Error Trace: /home/runner/work/nydus-snapshotter/nydus-snapshotter/tests/converter_test.go:303
/home/runner/work/nydus-snapshotter/nydus-snapshotter/tests/converter_test.go:589
/home/runner/work/nydus-snapshotter/nydus-snapshotter/tests/converter_test.go:566
Error: Received unexpected error:
exit status 1
unpack
github.com/containerd/nydus-snapshotter/pkg/converter.Unpack
/home/runner/work/nydus-snapshotter/nydus-snapshotter/pkg/converter/convert_unix.go:675
github.com/containerd/nydus-snapshotter/tests.unpackLayer
/home/runner/work/nydus-snapshotter/nydus-snapshotter/tests/converter_test.go:300
github.com/containerd/nydus-snapshotter/tests.testUnpack
/home/runner/work/nydus-snapshotter/nydus-snapshotter/tests/converter_test.go:589
github.com/containerd/nydus-snapshotter/tests.TestUnpack
/home/runner/work/nydus-snapshotter/nydus-snapshotter/tests/converter_test.go:566
testing.tRunner
/opt/hostedtoolcache/go/1.19.6/x64/src/testing/testing.go:1446
runtime.goexit
/opt/hostedtoolcache/go/1.19.6/x64/src/runtime/asm_amd64.s:1594
Test: TestUnpack
--- FAIL: TestUnpack (0.14s)
=== RUN TestImageConvert
time="2023-04-28T03:25:25Z"

[changweige]

Could you please share a page showing this newly added coverage action results?

[adamqqqplay]

Could you please share a page showing this newly added coverage action results?

@changweige This PR does not add a new action, it just adds a coverage check to the existing action, you can refer to following links. They are a check result of this PR: dragonflyoss/nydus#1225

1. https://github.com/dragonflyoss/image-service/runs/12950553738
2. https://github.com/dragonflyoss/image-service/runs/12950553733