Fixed k8s client unit test panic

[alexemc]

Description

Fixed k8s client unit test panic when running on a machine without kube config. The client GetKubeAPIServerVersion() function did not allow setting fake client, instead it always tried to initialize a real k8s client and crashed if there were no kube config present on the machine.

Example of the failure:

[root@lglw1113 csm-operator]#
[root@lglw1113 csm-operator]# make test
test -s /root/csm/csm-operator/bin/controller-gen && /root/csm/csm-operator/bin/controller-gen --version | grep -q v0.15.0 || \
GOBIN=/root/csm/csm-operator/bin go install sigs.k8s.io/controller-tools/cmd/controller-gen@v0.15.0
/root/csm/csm-operator/bin/controller-gen rbac:roleName=manager-role crd webhook paths="./..." output:crd:artifacts:config=config/crd/bases
/root/csm/csm-operator/bin/controller-gen object:headerFile="hack/boilerplate.go.txt" paths="./..."
(cd core; rm -f core_generated.go; go generate)
go run core/semver/semver.go -f mk > semver.mk
go fmt ./...
core/core_generated.go
go vet ./...
KUBEBUILDER_ASSETS="/root/.local/share/kubebuilder-envtest/k8s/1.25.0-linux-amd64" go test ./... -coverprofile cover.out
        github.com/dell/csm-operator/api/v1             coverage: 0.0% of statements
        github.com/dell/csm-operator            coverage: 0.0% of statements
        github.com/dell/csm-operator/core               coverage: 0.0% of statements
        github.com/dell/csm-operator/core/semver                coverage: 0.0% of statements
?       github.com/dell/csm-operator/pkg/constants      [no test files]
        github.com/dell/csm-operator/pkg/logger         coverage: 0.0% of statements
        github.com/dell/csm-operator/pkg/resources/configmap            coverage: 0.0% of statements
        github.com/dell/csm-operator/pkg/resources/csidriver            coverage: 0.0% of statements
        github.com/dell/csm-operator/pkg/resources/daemonset            coverage: 0.0% of statements
        github.com/dell/csm-operator/pkg/resources/deployment           coverage: 0.0% of statements
        github.com/dell/csm-operator/pkg/resources/rbac         coverage: 0.0% of statements
        github.com/dell/csm-operator/pkg/resources/serviceaccount               coverage: 0.0% of statements
        github.com/dell/csm-operator/pkg/resources/statefulset          coverage: 0.0% of statements
        github.com/dell/csm-operator/pkg/utils          coverage: 0.0% of statements
        github.com/dell/csm-operator/tests/shared               coverage: 0.0% of statements
        github.com/dell/csm-operator/tests/shared/clientgoclient                coverage: 0.0% of statements
        github.com/dell/csm-operator/tests/shared/crclient              coverage: 0.0% of statements
ok      github.com/dell/csm-operator/controllers        54.806s coverage: 67.9% of statements
--- FAIL: Test_GetVersion (1.00s)
    --- FAIL: Test_GetVersion/success_ (1.00s)
panic: runtime error: invalid memory address or nil pointer dereference [recovered]
        panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x12e503d]

goroutine 28 [running]:
testing.tRunner.func1.2({0x17bdc20, 0x28be9d0})
        /usr/local/go/src/testing/testing.go:1631 +0x24a
testing.tRunner.func1()
        /usr/local/go/src/testing/testing.go:1634 +0x377
panic({0x17bdc20?, 0x28be9d0?})
        /usr/local/go/src/runtime/panic.go:770 +0x132
k8s.io/client-go/discovery.NewDiscoveryClientForConfig(0x0?)
        /root/go/pkg/mod/k8s.io/client-go@v0.27.2/discovery/discovery_client.go:711 +0x1d
github.com/dell/csm-operator/k8s.GetKubeAPIServerVersion()
        /root/csm/csm-operator/k8s/client.go:49 +0x4a
github.com/dell/csm-operator/k8s.Test_GetVersion.func3(0xc0002b5d40)
        /root/csm/csm-operator/k8s/client_test.go:169 +0xec
testing.tRunner(0xc0002b5d40, 0xc0000566d0)
        /usr/local/go/src/testing/testing.go:1689 +0xfb
created by testing.(*T).Run in goroutine 27
        /usr/local/go/src/testing/testing.go:1742 +0x390
FAIL    github.com/dell/csm-operator/k8s        1.037s
ok      github.com/dell/csm-operator/pkg/drivers        0.168s  coverage: 41.4% of statements
ok      github.com/dell/csm-operator/pkg/modules        1.442s  coverage: 60.1% of statements
FAIL
make: *** [Makefile:78: test] Error 1
[root@lglw1113 csm-operator]#

GitHub Issues

None.

Checklist:

• I have performed a self-review of my own code to ensure there are no formatting, vetting, linting, or security issues
• I have verified that new and existing unit tests pass locally with my changes
• I have not allowed coverage numbers to degenerate
• I have maintained backward compatibility

How Has This Been Tested?

Unit tests passed with the fix:

[root@lglw1113 csm-operator]#
[root@lglw1113 csm-operator]# make test
test -s /root/csm/csm-operator/bin/controller-gen && /root/csm/csm-operator/bin/controller-gen --version | grep -q v0.15.0 || \
GOBIN=/root/csm/csm-operator/bin go install sigs.k8s.io/controller-tools/cmd/controller-gen@v0.15.0
/root/csm/csm-operator/bin/controller-gen rbac:roleName=manager-role crd webhook paths="./..." output:crd:artifacts:config=config/crd/bases
/root/csm/csm-operator/bin/controller-gen object:headerFile="hack/boilerplate.go.txt" paths="./..."
(cd core; rm -f core_generated.go; go generate)
go run core/semver/semver.go -f mk > semver.mk
go fmt ./...
core/core_generated.go
go vet ./...
KUBEBUILDER_ASSETS="/root/.local/share/kubebuilder-envtest/k8s/1.25.0-linux-amd64" go test ./... -coverprofile cover.out
        github.com/dell/csm-operator/api/v1             coverage: 0.0% of statements
        github.com/dell/csm-operator            coverage: 0.0% of statements
        github.com/dell/csm-operator/core               coverage: 0.0% of statements
        github.com/dell/csm-operator/core/semver                coverage: 0.0% of statements
?       github.com/dell/csm-operator/pkg/constants      [no test files]
        github.com/dell/csm-operator/pkg/logger         coverage: 0.0% of statements
        github.com/dell/csm-operator/pkg/resources/configmap            coverage: 0.0% of statements
        github.com/dell/csm-operator/pkg/resources/csidriver            coverage: 0.0% of statements
        github.com/dell/csm-operator/pkg/resources/daemonset            coverage: 0.0% of statements
        github.com/dell/csm-operator/pkg/resources/deployment           coverage: 0.0% of statements
        github.com/dell/csm-operator/pkg/resources/rbac         coverage: 0.0% of statements
        github.com/dell/csm-operator/pkg/resources/serviceaccount               coverage: 0.0% of statements
        github.com/dell/csm-operator/pkg/resources/statefulset          coverage: 0.0% of statements
        github.com/dell/csm-operator/pkg/utils          coverage: 0.0% of statements
        github.com/dell/csm-operator/tests/shared               coverage: 0.0% of statements
        github.com/dell/csm-operator/tests/shared/clientgoclient                coverage: 0.0% of statements
        github.com/dell/csm-operator/tests/shared/crclient              coverage: 0.0% of statements
ok      github.com/dell/csm-operator/controllers        54.667s coverage: 67.9% of statements
ok      github.com/dell/csm-operator/k8s        0.061s  coverage: 83.9% of statements
ok      github.com/dell/csm-operator/pkg/drivers        0.170s  coverage: 41.4% of statements
ok      github.com/dell/csm-operator/pkg/modules        1.416s  coverage: 60.1% of statements
[root@lglw1113 csm-operator]#

[chimanjain]

Can we also update the k8s version to the latest supported version from k8s/1.25.0.