TestGetKubeConfig unit test failing

[RomanBednar]

What type of PR is this?
/kind test
/kind bug

What this PR does / why we need it:

Fixes a failing unit test.

Which issue(s) this PR fixes:

Fixes #1293

Requirements:

• uses conventional commit messages
• includes documentation
• adds unit tests
• tested upgrade from previous version

Special notes for your reviewer:

Release note:

none

[andyzhangx]

is it possible only skip this test in OpenShift coreos?

[jsafrane]

IMO an unit test that checks system directories is a bad test. [failure] invalid kube config passed tests getKubeConfig() with an empty kubeconfig file.

This leads to this call stack:

clientcmd.(*DeferredLoadingClientConfig).ClientConfig (merged_client_builder.go:120) k8s.io/client-go/tools/clientcmd
clientcmd.BuildConfigFromFlags (client_config.go:627) k8s.io/client-go/tools/clientcmd
azurefile.getKubeConfig (azure.go:156) sigs.k8s.io/azurefile-csi-driver/pkg/azurefile
azurefile.TestGetKubeConfig (azure_test.go:422) sigs.k8s.io/azurefile-csi-driver/pkg/azurefile

DeferredLoadingClientConfig.ClientConfig() then fails to load the empty kubeconfig, but as a fallback, it tries to load in-cluster config. And that's where it finds out that it's just a Pod in our CI and loads Kubernetes service account and therefore succeeds, instead of returning error.

azurefile-csi-driver/vendor/k8s.io/client-go/tools/clientcmd/merged_client_builder.go

Lines 119 to 123 in ae84f9a

	// check for in-cluster configuration and use it
	if config.icc.Possible() {
	klog.V(4).Infof("Using in-cluster configuration")
	return config.icc.ClientConfig()
	}

With the env. variables unset, Possible() it will return error here:

azurefile-csi-driver/vendor/k8s.io/client-go/tools/clientcmd/client_config.go

Lines 603 to 609 in 817a13b

	// Possible returns true if loading an inside-kubernetes-cluster is possible.
	func (config *inClusterClientConfig) Possible() bool {
	fi, err := os.Stat("/var/run/secrets/kubernetes.io/serviceaccount/token")
	return os.Getenv("KUBERNETES_SERVICE_HOST") != "" &&
	os.Getenv("KUBERNETES_SERVICE_PORT") != "" &&
	err == nil && !fi.IsDir()
	}

I don't know what magic Kubernetes CI does so that Possible() fails, most probably it does not create /var/run/secrets/kubernetes.io/serviceaccount/token. But an unit test result should not depend on presence of any files in /var/run.

[andyzhangx]

/lgtm

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: andyzhangx, RomanBednar

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[andyzhangx]

/retest