add unit-test for apis/opts/ports.go

[liuxuan1-1]

Ⅰ. Describe what this PR did

add a unit-test for ports.go

Ⅱ. Does this pull request fix one issue?

fix issues #1906

Ⅲ. Describe how you did it

Build unit test by condition combination coverage(ccc).

Ⅳ. Describe how to verify it

By code review and walk-through

Ⅴ. Special notes for reviews

[pouchrobot]

@TheKiteRunners Thanks for your contribution. 🍻
Please sign off in each of your commits.

[CLAassistant]

Thank you for your submission, we really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.

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[pouchrobot]

We found this is your first time to contribute to Pouch, @TheKiteRunners
👏 We really appreciate it.
Just remind that you have read the contribution guide: https://github.com/alibaba/pouch/blob/master/CONTRIBUTING.md
If you didn't, you should do that first. If done, welcome again and please enjoy hacking! 🍻

[codecov-io]

Codecov Report

❗ No coverage uploaded for pull request head (lzx@4b04d4c). Click here to learn what that means.
The diff coverage is n/a.