Powershell pester script with various examples of using pester for operational validation.

Test-Pester.tests.ps1

Describe  'My process checks' {
    
    Context 'Checking essential Windows processes are running' {

        It 'winlogon.exe is running' {
            get-process -Name 'winlogon' | Should be $true
        }
        
    }

    $CPUThreshold = 10

    Context "Checking for processes using > $CPUThreshold% CPU" {
    
            $CpuCores = (Get-WMIObject Win32_ComputerSystem).NumberOfLogicalProcessors
            $Samples = (Get-Counter “\Process(*)\% Processor Time” -ErrorAction SilentlyContinue).CounterSamples
            $Samples | Select InstanceName,@{Name=”CPU”;Expression={[Decimal]::Round(($_.CookedValue / $CpuCores), 2)}} `
            | Sort-Object InstanceName `
            | Where-Object {$_.InstanceName -ne "idle" -and $_.InstanceName -ne "_total"} `
            | ForEach-Object {

                It "Process $($_.InstanceName) is using $($_.CPU)% CPU" {
                    $_.CPU | Should Not BeGreaterThan 10 
                }

            }
    }

}

Describe  'Weird science checks' {
    
    Context 'Checking for the impossible' {

        It 'It should be opposite day' {
            $true | Should be $false
        }
        
    }
}

Describe  'Day of the week check' {
    
    $WeekDays = "Monday","Tuesday","Wednesday","Thursday","Friday","Saturday","Sunday"

    $WeekDays | ForEach-Object {

        It "Today should be $_" {
            (get-date).DayOfWeek | Should be $_
        }
    }     
}

Describe 'Operating System check' {

    It 'C:\Windows folder exists' {
       'C:\Windows' | Should Exist
    }

    It 'C:\Linux folder does not exist' {
       'C:\Linux' | Should Not Exist
    }

}

Describe  'Windows service check' {
    
    Get-Service -DisplayName "Windows*" | ForEach-Object {

        It "The $($_.DisplayName) service should be running" {
            $_.Status | Should be 'Running'
        }
    }     
}

Blog: https://wragg.io/getting-started-with-pester-for-operational-testing/