Test-Connection to catch offline machine and put results in exel file

I would like to integrate Test-Connection  command   into my existing script id like it it to test if machine is online if online continue working,  if machine is offline  dump offline machines into the Results.cvs   file

Secondly , is there a way with Get-Credential to test local IP , to know rest of the IPs or computers are remote ?

here is my existing script :

#Define parameters
param(  
  [String[]]$ComputerName=$env:computername,
                [String]$FilePath = "C:\Users\gdrews\Downloads\ComputerInfo.txt",
  [switch]$LogReport   
  )

    
  
#Define function to generate report.
function Get-ComputerInfo
 { $c = get-credential administrator
   foreach ($Comp in $ComputerName)
   #if (test-connection $Comp -quiet -count 1)
     
   {
     
    Write-host "Working on $Comp"

    $Date = Get-Date  
    
    $CompInfo = Get-WmiObject -Class Win32_ComputerSystem -ComputerName $Comp -credential $c  
    $OSInfo = Get-WmiObject -Class Win32_OperatingSystem -ComputerName $Comp -credential $c
    $Bios = Get-WmiObject Win32_BIOS -ComputerName $Comp -credential $c
    $CPUInfo = Get-WmiObject Win32_Processor -ComputerName $Comp -credential $c
    
    
    $Computer = $CompInfo.Name
    $Domain = $CompInfo.Domain
    $User = $CompInfo.UserName
    $OS = $OSInfo.Caption
    $Installdate = $OSInfo.ConvertToDateTime($OSInfo.installDate)
    $Model = $CompInfo.Model
    $CPU = $CPUInfo.Name
    $RAM = "{0:n2} GB" -f ($CompInfo.TotalPhysicalMemory/1gb)
    $SystemType = $CompInfo.SystemType
    $uptime = Get-Uptime
          $Disk = GetDriveInfo $Comp

    ""
    "PC Name   : $Computer"
    "User Name : $User"
    "Model    : $Model"
    "Domain   : $Domain"
    "OS        : $OS"
    "Uptime    : $uptime"
    "Install Date : $Installdate"
    "RAM   : $RAM"
    "Disk      :    $Disk"
    "SystemType  : $SystemType"
    "CPU   :    $CPU"
     
    #"User information collected on : $date" 
    ""

   }
       
 }

function GetDriveInfo{
    Param($Comp)
    # Get disk sizes
    $logicalDisk = Get-WmiObject Win32_LogicalDisk -Filter "DriveType=3" -ComputerName $comp -credential $c
    foreach($disk in $logicalDisk)
    {
        $diskObj = "" | Select-Object Disk,Size,FreeSpace
        $diskObj.Disk = $disk.DeviceID
        $diskObj.Size = "{0:n0} GB" -f (($disk | Measure-Object -Property Size -Sum).sum/1gb)
        $diskObj.FreeSpace = "{0:n0} GB" -f (($disk | Measure-Object -Property FreeSpace -Sum).sum/1gb)

        $text = "{0}  {1}  Free: {2}" -f $diskObj.Disk,$diskObj.size,$diskObj.Freespace
          $msg += $text + "         `r`n         " + "           `r`n               "
  
    }
   $msg
}

function Get-Uptime {
   $OSInfo = Get-WmiObject win32_operatingsystem
   $uptime = (Get-Date) - ($OSInfo.ConvertToDateTime($OSInfo.lastbootuptime))
   $Display = "Uptime: " + $Uptime.Days + " days, " + $Uptime.Hours + " hours, " + $Uptime.Minutes + " minutes"
   Write-Output $Display
}

#Entry point to script   
 Get-ComputerInfo   
 if($LogReport)
  {
  Get-ComputerInfo | Out-File -FilePath $FilePath -encoding ASCII -Append
  }