Strip the version prefix before calling semver

[afbjorklund]

Needs a mirror country unit test, apparently.

Closes #7052

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[codecov-io]

Codecov Report

Merging #7054 into master will increase coverage by 0.29%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #7054      +/-   ##
==========================================
+ Coverage   36.94%   37.24%   +0.29%     
==========================================
  Files         146      146              
  Lines        9094     9094              
==========================================
+ Hits         3360     3387      +27     
+ Misses       5322     5292      -30     
- Partials      412      415       +3

Impacted Files	Coverage Δ
cmd/minikube/cmd/start.go	38.47% <100%> (+4.67%)	⬆️

[afbjorklund]

Test seems to be working as intended, catches the previous error which was the idea:

=== RUN   TestMirrorCountry
=== RUN   TestMirrorCountry/image-repository_none,_image-mirror-country_none
=== RUN   TestMirrorCountry/image-repository_auto,_image-mirror-country_none
panic: semver: Parse(v1.17.3): Invalid character(s) found in major number "v1" [recovered]
	panic: semver: Parse(v1.17.3): Invalid character(s) found in major number "v1"

It doesn't really verify the repository though, since it could still be defined as empty:

        // ImageRepositories contains all known image repositories
        ImageRepositories = map[string][]string{
                "global": {""},
                "cn":     {"registry.cn-hangzhou.aliyuncs.com/google_containers"},
        }

[medyagh]

Calling viper.Set in unit test has un-wanted side effects, such as setting the user 's settings and also can not run in parallel safely

Could we break down generateCfgFromFlags func so we can test only the mirror func without need to pass cobra ?

[afbjorklund]

No idea, think I only copied what the test above was doing or something

                        viper.SetDefault(kubernetesVersion, test.paramVersion)

[medyagh]

I think we can refactor our tests not to use viper as much as possible, we could parameterize the funcs into small independent testable units. what do u think? maybe good opprotunity to refactor this part of the code?