test: add test cases about toCNIPortMappings

[starnop]

Signed-off-by: Starnop [email protected]

Ⅰ. Describe what this PR did

Ⅱ. Does this pull request fix one issue?

fixes part of #1756

Ⅲ. Describe how you did it

Ⅳ. Describe how to verify it

Ⅴ. Special notes for reviews

[codecov-io]

Codecov Report

Merging #2050 into master will decrease coverage by 0.03%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #2050      +/-   ##
==========================================
- Coverage   64.02%   63.98%   -0.04%     
==========================================
  Files         202      202              
  Lines       15510    15510              
==========================================
- Hits         9930     9924       -6     
- Misses       4343     4347       +4     
- Partials     1237     1239       +2

Flag	Coverage Δ
#criv1alpha1test	33.75% <ø> (+0.15%)	⬆️
#criv1alpha2test	34.21% <ø> (-0.1%)	⬇️
#integrationtest	38.45% <ø> (-0.05%)	⬇️
#unittest	22.71% <ø> (+0.17%)	⬆️

Impacted Files	Coverage Δ
ctrd/watch.go	69.69% <0%> (-6.07%)	⬇️
ctrd/image.go	76.84% <0%> (-1.98%)	⬇️
cri/v1alpha2/cri.go	66.02% <0%> (-0.18%)	⬇️
daemon/mgr/container.go	53.93% <0%> (+0.15%)	⬆️
cri/v1alpha1/cri.go	65.36% <0%> (+0.17%)	⬆️

[YaoZengzeng]

LGTM