Add more testing

[hwchiu]

• Add the testing for gRPC
• Add the testing for invalid FindK8SPauseContainerIDFail case

[codecov]

Codecov Report

Merging #8 into master will increase coverage by 20.54%.
The diff coverage is 100%.

@@             Coverage Diff             @@
##           master       #8       +/-   ##
===========================================
+ Coverage   60.27%   80.82%   +20.54%     
===========================================
  Files           3        3               
  Lines          73       73               
===========================================
+ Hits           44       59       +15     
+ Misses         23       12       -11     
+ Partials        6        2        -4

Impacted Files	Coverage Δ
openvswitch/ovs.go	92.3% <100%> (+23.07%)	⬆️
docker/pause-container.go	100% <0%> (+33.33%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update a1df18b...40f92f5. Read the comment docs.