test: cover storage access mode defaulting

[mehrdadbn9]

storageSpec.accessModes is optional, and leaving it unset used to produce a volume claim template with accessModes: [""], which the API server rejects, so every pod stayed pending. That is what #107 reported.

It was already fixed in 3905389 ("Defaults to ReadWriteOnce when it's empty or not provided"), which is why the recent attempts to reproduce it came back clean. Nothing covers that defaulting though, so it can be dropped again without a test going red - the e2e cases always set accessModes: ReadWriteOnce explicitly, so they never touch the empty path.

This adds a table-driven test over createOrPatchStatefulSet for the access mode branches:

• unset -> claim template gets ReadWriteOnce (the StorageSpec accessMode is not required but errors if not provided #107 case)
• explicit ReadWriteOnce -> kept
• ReadWriteMany + pvcName -> no claim template, pod volume references the named PVC
• ReadWriteMany without pvcName -> rejected
• unsupported mode (ReadOnlyMany) -> rejected

Verification

Reverting 3905389 locally (putting ec.Spec.StorageSpec.AccessModes back in the claim template) turns exactly the first case red and leaves the other four green:

--- FAIL: TestCreateOrPatchStatefulSetStorageAccessModes/defaults_to_ReadWriteOnce_when_accessModes_is_not_provided
    Error: Not equal:
      expected: []v1.PersistentVolumeAccessMode{"ReadWriteOnce"}
      actual  : []v1.PersistentVolumeAccessMode{""}

which is the same accessModes: [''] from the original report. With the fix in place the whole package is green, and make lint reports 0 issues.

Test only, no production code touched.

Refs #107

[kubernetes-prow]

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[kubernetes-prow]

Hi @mehrdadbn9. Thanks for your PR.

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