Test-NetPort.ps1

function Test-NetPort {
    [CmdletBinding()]
    [OutputType([Boolean])]
    param (
        [Parameter(Mandatory,
                   ValueFromPipeline,
                   ValueFromPipelineByPropertyName)]
        [String] $ComputerName,

        [Parameter(Mandatory,
                   ValueFromPipeline,
                   ValueFromPipelineByPropertyName)]
        [Int] $Port,

        [Int] $Timeout = 2
    )

    process {
        $TCPConnect = New-Object -TypeName System.Net.Sockets.TcpClient
        Write-Verbose -Message "Attempting connection to computer: $ComputerName on TCP port: $Port"
        try {
            $TCPConnect.ConnectAsync($ComputerName,$Port).Wait([timespan]::FromSeconds($Timeout))
        } catch [ArgumentOutOfRangeException] {
            Write-Error -Message 'Port defined was out of range' -ErrorAction Continue
            $false
        } catch [AggregateException] {
            Write-Warning -Message $_.Exception.InnerException.Message
            $false
        } catch {
            Write-Error -ErrorRecord $_ -ErrorAction Continue
        } finally {
            $TCPConnect.Dispose()
        }
    }
}

Test-NetPort -ComputerName dc.lab.local -Port 3389 
'dc.lab.local' | Test-NetPort -Port 389
[PSCustomObject]@{ComputerName = 'dc.lab.local';Port='5985'} | Test-NetPort

#waits for port to become available or until 5 minutes have passed
$i = 0
do {
    $i++
    $WSMAN = Test-NetPort -ComputerName dc.lab.local -Port 5985 -Timeout 3
} until ($WSMAN -or $i -eq 100)

Requires .NET 4.5.
Test-NetConnection does not have a timeout option and only allows port check from Windows 2012R2+
Specially handy in do until loop to check if port has become available (no need for start-sleep).