add more unit tests to increase test coverage

[ElijahQuinones]

Is this a bug fix or adding new feature? This adds more units tests for more code coverage.

What is this PR about? / Why do we need it? As driver and Cloud coverage are both below 90% coverage this PR is to add more coverage to those areas

What testing is done? Ran the unit tests to validate they pass and ran make test/coverage to verify that the coverage had increased after each unit test was added

[k8s-ci-robot]

Hi @ElijahQuinones. Thanks for your PR.

I'm waiting for a kubernetes-sigs member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

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[ElijahQuinones]

This initial PR is just to get feedback from the team so the rest of the tests going forward that I write can conform to the same format.

[torredil]

/ok-to-test

This initial PR is just to get feedback from the team so the rest of the tests going forward that I write can conform to the same format.

@ElijahQuinones It's looking good!- inputs/outputs are being parameterized which makes sense and the tests are written in a table-driven manner, which is considered a best practice.

[AndrewSirenko]

Looks great to me so far! +1 To eddie's points. Readable tests with no over-reliance on mocking is a great sign as well.

[github-actions[bot]]

Code Coverage Diff

File	Old Coverage	New Coverage	Delta
github.com/kubernetes-sigs/aws-ebs-csi-driver/pkg/cloud/cloud.go	85.7%	88.9%	3.2
github.com/kubernetes-sigs/aws-ebs-csi-driver/pkg/cloud/handlers.go	0.0%	4.8%	4.8
github.com/kubernetes-sigs/aws-ebs-csi-driver/pkg/driver/controller.go	82.8%	83.8%	1.0
github.com/kubernetes-sigs/aws-ebs-csi-driver/pkg/driver/controller_modify_volume.go	72.3%	78.3%	6.0
github.com/kubernetes-sigs/aws-ebs-csi-driver/pkg/driver/driver.go	0.0%	26.3%	26.3
github.com/kubernetes-sigs/aws-ebs-csi-driver/pkg/driver/validation.go	87.8%	97.3%	9.5

[ElijahQuinones]

/retest

[ConnorJC3]

/lgtm

[torredil]

/lgtm

[torredil]

/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: torredil

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Needs approval from an approver in each of these files: - ~~[OWNERS](https://github.com/kubernetes-sigs/aws-ebs-csi-driver/blob/master/OWNERS)~~ [torredil] Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment