PowerShell Error Handling Output Testing

Error-HandlingTest.ps1

function Test-Func {
    try {
        $NewVagrantBoxResult = New-VagrantBox -VagrantBox "centos/7" -ErrorVariable NVBErr -ErrorAction SilentlyContinue
        if (!$NewVagrantBoxResult) {throw "The New-VagrantBox function failed!"}

        $NewVagrantBoxResult
    }
    catch {
        Write-Error $_
        Write-Error $($NVBErr | Out-String)
        #Write-Error $($NVBErr.ScriptStackTrace | Out-String)
        $global:FunctionResult = "1"
        return
    }
}

function New-VagrantBox {
    [CmdletBinding()]
    Param (
        [Parameter(Mandatory=$False)]
        [string]$VagrantBox
    )

    if (![bool]$(Get-Command vagrant -ErrorAction SilentlyContinue)) {
        try {
            $InstallProgramResult = Install-Program -ProgramName "vagrant" -ErrorVariable IPErr -ErrorAction SilentlyContinue
            if (!$InstallProgramResult) {throw "The Install-Program function failed!"}
        }
        catch {
            Write-Error $_
            Write-Error $($IPErr | Out-String)
            #Write-Error $($IPErr.ScriptStackTrace | Out-String)
            $global:FunctionResult = "1"
            return
        }
    }

    Write-Output "New-VagrantBox Success"
}

function Install-Program {
    [CmdletBinding()]
    Param (
        [Parameter(Mandatory=$False)]
        [string]$ProgramName
    )

    if (![bool]$(Get-Command choco -ErrorAction SilentlyContinue)) {
        try {
            $InstallChocoResult = Install-ChocolateyCmdLine -ErrorVariable ICCErr -ErrorAction SilentlyContinue
            if (!$InstallChocoResult) {throw "The Install-ChocolateyCmdLine function failed!"}
        }
        catch {
            Write-Error $_
            Write-Error $($ICCErr | Out-String)
            #Write-Error $($ICCErr.ScriptStackTrace | Out-String)
            $global:FunctionResult = "1"
            return
        }
    }

    Write-Output "Install-Program Success"
}

function Install-ChocolateyCmdLine {
    [CmdletBinding()]
    Param (
        [Parameter(Mandatory=$False)]
        [switch]$UseChocoOrgInstallScript
    )

    try {
        1/0
    }
    catch {
        Write-Error $_
        $global:FunctionResult = "1"
        return
    }

    Write-Output "Install-ChocolateyCmdLine Success"
}