Prequel 1 - Flawless Faction

Prequel1.ps1

Function Get-ComputerInfo {
    Param (
        [Parameter(Position=1, ValueFromPipelineByPropertyName=$True, ValueFromPipeline=$True)]
        [alias('Computer','Host','Hostname','Server','ServerName')]
        [String[]]$ComputerName = $env:computername,

        [pscredential]$Credential = $Null
    )
    BEGIN{
        $ErrorActionPreference = 'Stop'
        $FunctionName = $pscmdlet.MyInvocation.InvocationName.ToUpper()
        write-verbose "$FunctionName`:  Begin Function"
    }
    PROCESS {
        Foreach ($Computer in $Computername){
            Write-Verbose "$FunctionName`: Attempting data retrieval via CIM for $computer"
            Try {
                If ($Credential){
                    $Monitorinfo = Start-job -scriptblock {Get-CIMInstance -Namespace root\wmi -Class wmiMonitorID -ComputerName $args[0]} -argumentlist $computer -Credential $Credential | wait-job | receive-job
                    $Computerinfo = start-job -scriptblock {Get-CIMInstance -Class Win32_ComputerSystem -ComputerName $args[0]} -argumentlist $computer -Credential $Credential | wait-job | receive-job
                    $BIOSinfo = start-job -scriptblock {Get-CIMInstance -Class Win32_BIOS -ComputerName $args[0]} -argumentlist $computer -Credential $Credential | wait-job | receive-job
                } else {
                    $Monitorinfo = Get-CIMInstance -Namespace root\wmi -Class wmiMonitorID -ComputerName $computer
                    $Computerinfo = Get-CIMInstance -class Win32_ComputerSystem -ComputerName $computer
                    $BIOSinfo = Get-CIMInstance -class Win32_BIOS -ComputerName $computer
                    
                }
            } Catch {
                Write-verbose "$FunctionName`: Unable to retrieve data via WMI method.  Attempting WSMan connection."
                write-verbose "$FunctionName`: Error message $_"
            }
            If (($null -eq $MonitorInfo -or $null -eq $computerinfo -or $Null -eq $BIOSinfo) -and ($computer -ne $env:computername)){
                Try {
                    If ($Credential){
                        $Session = New-PSSession -ComputerName $Computer -Credential $Credential
                    } else {
                        $Session = New-PSSession -ComputerName $Computer
                    }
                    $Computerinfo = Invoke-command -ScriptBlock {Get-CIMInstance -class Win32_ComputerSystem} -Session $Session
                    $BIOSinfo = Invoke-command -ScriptBlock {Get-CIMInstance -class Win32_BIOS} -Session $Session
                    $Monitorinfo = Invoke-command -ScriptBlock {Get-CIMInstance -namespace root\wmi -class wmiMonitorID} -Session $Session -ErrorAction SilentlyContinue
                    Remove-PSSession $Session
                } Catch {
                    Remove-PSSession $Session
                    write-error "Unable to connect to $Computer. Error code`: $_"
                    return
                }
            }
            $output = New-object psobject -property @{
                'ComputerName' = $Computer
                'MonitorInfo' = ''
                'ComputerType' = ''
                'ComputerSerial' = ''
            }
            If ($MonitorInfo){
                $monitors=@()
                foreach ($monitor in $monitorinfo){
                    $monitors += new-object psobject -property @{
                        'MonitorSerial' = [System.Text.Encoding]::Default.GetString($Monitor.SerialNumberID)
                        'MonitorType' = [System.Text.Encoding]::Default.GetString($monitor.UserFriendlyName)
                    }
                $output.MonitorInfo = $monitors
                }
            }
            If ($ComputerInfo){
                $output.ComputerType = $computerinfo.model
            }
            If ($Biosinfo){
                $output.ComputerSerial = $BIOSinfo.serialnumber
            }
            return $output
        }
    }
}

Prequel1.tests.ps1

$here = Split-Path -Parent $MyInvocation.MyCommand.Path
$sut = (Split-Path -Leaf $MyInvocation.MyCommand.Path) -replace '\.Tests\.', '.'
. "$here\$sut"

Describe -Name "Unit Testing Get-ComputerInfo" -Fixture {
    Context -Name "Mock Functions" -Fixture {
        Mock -CommandName Get-CimInstance -MockWith {
            [pscustomobject]@{
                name = $ComputerName
                model = 'PHILIPS'
            }
        } -ParameterFilter { $ClassName -and $ClassName -eq "Win32_ComputerSystem"} #Get-CimInstance Mock
        Mock -CommandName Get-CimInstance -MockWith {
            [pscustomobject]@{
                SerialNumber = '1234568'
            }
        } -ParameterFilter { $ClassName -and $ClassName -eq "Win32_BIOS"} #Get-CimInstance Mock
        Mock -CommandName Get-CimInstance -MockWith {
            [pscustomobject]@{
                UserFriendlyName = @('109','111','99','107','101','100')
                SerialNumberID = @('56','54','55','53','51','48','57')
            }#PSCustomObject
        } -ParameterFilter { $ClassName -and $ClassName -eq "wmiMonitorID"} #Get-CimInstance Mock#Mock Get-Ciminstance
        
        $Result = Get-ComputerInfo
        It -name "Assert Mock called - Get-CimInstance" -test {
            Assert-MockCalled -CommandName Get-CimInstance -Times 1 -ParameterFilter { $ClassName -and $ClassName -eq "Win32_ComputerSystem"}
            Assert-MockCalled -CommandName Get-CimInstance -Times 2
        }#It
        It -name "Result is not null" -test{
            $Result | Should not beNullOrEmpty
        }#It
        It -name "MonitorType is mocked" -test{
            $Result.monitorinfo.MonitorType | Should be "Mocked"
        }#It
        It -name "ComputerName matches env:ComputerName" -test{
            $Result.ComputerName | Should be $env:ComputerName
        }#It
        It -name "ComputerSerial is mocked" -test {
            $Result.ComputerSerial | Should be '1234568'
        }#It
        It -name "MonitorSerial is mocked" -test {
            $Result.monitorinfo.MonitorSerial | Should be '8675309'
        }#It
        It -name "Processes computername parameter from pipeline input" -test {
            $result = 'computer1','computer2' | get-computerinfo
            $result[0].Computername | should be 'computer1'
            $result[1].Computername | should be 'computer2'
        }
        It -name "Processes computername parameter as property of input object" -test {
            $inputobject = [pscustomobject]@{Computername='computer1'}
            $Result = $inputobject | get-computerinfo
            $result.Computername | should be 'computer1'
        }
        It -name "Processes multiple computernames as properties of input objects with alias" -test {
            $inputarray = @()
            $inputarray += [pscustomobject]@{host='computer1'}
            $inputarray += [pscustomobject]@{host='computer2'}
            $Result = $inputarray | get-computerinfo
            $result[0].Computername | should be 'computer1'
            $Result[1].Computername | should be 'computer2'
        }
    }#Context Mock Functions
    Context -Name "No Mocked Functions" -Fixture {
        $Result = Get-ComputerInfo
        It -name "Result is not null" -test{
            $Result | Should not beNullOrEmpty
        }#It
    }#Context no mocked functions
}#Describe