Fix the unit tests

[kceiw]

Description

In previous check in there was a change to create the PowerShell Runtime when the module is imported. But the unit tests don't set up the PowerShell environment. The creation of PowerShell runtime will fail.

The fix is to abstract PowerShellRuntime to an interface IPowerShellRuntime. We create a mock of IPowerShellRuntime for the unit tests and we only initialize the needed properties. Thus we avoid creation of the PowerShell Runtime in the unit tests.

Checklist

• I have read the Submitting Changes section of CONTRIBUTING.md
• The title of the PR is clear and informative
• The appropriate ChangeLog.md file(s) has been updated:
  • For any service, the ChangeLog.md file can be found at src/{{SERVICE}}/{{SERVICE}}/ChangeLog.md
  • A snippet outlining the change(s) made in the PR should be written under the ## Upcoming Release header -- no new version header should be added
• The PR does not introduce breaking changes
• If applicable, the changes made in the PR have proper test coverage
• For public API changes to cmdlets:
  • a cmdlet design review was approved for the changes in this repository (Microsoft internal only)
    • {Please put the link here}
  • the markdown help files have been regenerated using the commands listed here

[wyunchi-ms]

/azp run azure-powershell - security-tools

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