Pester Test

[baristaTam]

Add a .Tests Pester file that uses Mock to verify the expected calls to 'Invoke-RestMethod' happen within Export-SplunkData

In case it's of value - here's a case where I have used with Mock in Pester to assert a method gets called (while preventing the actual call from happening):
https://github.com/uillinois-community/powershell-scripts/blob/4d0aa88edf33759e43d2221c2c4df012b9f95b8c/modules/AgileGitHub.Tests.ps1#L73