function Measure-HelpSynopsis {
<#
.SYNOPSIS
    Add a SYNOPSIS keyword in your comment-based help.
.DESCRIPTION
    Comment-based help is written as a series of comments. You can write comment-based help topics for end users to better understand your functions. Additionally, it's better to explain the detail about how the function works.
    To fix a violation of this rule, add a .SYNOPSIS keyword in your comment-based help. You can get more details by running: Get-Help about_Comment_Based_Help
.EXAMPLE
    Measure-HelpSynopsis -FunctionDefinitionAst $FunctionDefinitionAst
.INPUTS
    [System.Management.Automation.Language.FunctionDefinitionAst]
.OUTPUTS
    [Microsoft.Windows.Powershell.ScriptAnalyzer.Generic.DiagnosticRecord[]]
.NOTES
    Reference: Writing Help and Comments, Windows PowerShell Best Practices.
#>
    [CmdletBinding()]
    [OutputType([Microsoft.Windows.Powershell.ScriptAnalyzer.Generic.DiagnosticRecord[]])]
    Param
    (
        [Parameter(Mandatory = $true)]
        [ValidateNotNullOrEmpty()]
        [System.Management.Automation.Language.FunctionDefinitionAst]
        $FunctionDefinitionAst
    )

    Process {
        $results = @()
        $message = (Get-Help $MyInvocation.MyCommand.Name).Synopsis

        try {
            if (!$FunctionDefinitionAst.GetHelpContent().Synopsis) {
                $result = New-Object `
                            -Typename "Microsoft.Windows.PowerShell.ScriptAnalyzer.Generic.DiagnosticRecord" `
                            -ArgumentList $message,$FunctionDefinitionAst.Extent,$PSCmdlet.MyInvocation.InvocationName,Warning,$null

                $results += $result
            }

            return $results
        } catch {
            $PSCmdlet.ThrowTerminatingError($PSItem)
        }
    }
}