Windows PowerShell TFM Book Contest and Giveaway

ConvertTo-CapitalizedString.ps1

Function ConvertTo-CapitalizedString
{
<#
.SYNOPSIS
    Capitalizes the first character of a string
.PARAMETER Delimiter
    Uses space as default delimiter to split input strings. Delimiters can be single characters only.
.PARAMETER NoDelimiter
    Disable string splitting based on specified delimiter.
.EXAMPLE
    "ThE wINDOWS Powershell TFM book CONTEST aNd GiVeAwAy" | ConvertTo-CapitalizedString
    The Windows Powershell Tfm Book Contest And Giveaway
.EXAMPLE
    "ThE wINDOWS Powershell TFM book CONTEST aNd GiVeAwAy" | ConvertTo-CapitalizedString -NoDelimiter
    The windows powershell tfm book contest and giveaway
#>
    [CmdletBinding()]
    Param(
        [Parameter(Mandatory=$true,ValueFromPipeline=$true,Position=0)]
        [ValidateNotNullOrEmpty()]
        [string[]]
        $String,

        [Parameter(Position=1)]
        [ValidateNotNullOrEmpty()]
        [char]
        $Delimiter = ' ',

        [switch]
        $NoDelimiter
    )

    BEGIN 
    {
        $Result = New-object System.Collections.ArrayList

        Function New-CapitalizedString
        {
            Param($String)

            [string]$FirstCharacter = $String[0]
            [string]$Rest = $String.Remove(0,1)
            $FirstCharacter.ToUpper() + $Rest.ToLower() 
        }
    }

    PROCESS 
    {
        foreach($Element in $String)
        {
            Write-Verbose "Processing [$Element]"

            if($NoDelimiter)
            {
                $tmpString = New-CapitalizedString $Element
                Write-Verbose "Converted [$Element] to [$tmpString]"
            }
            else
            {
                Write-Verbose "Using delimiter [$Delimiter] to split [$Element]"

                $tmpString = foreach($Word in $Element.split($Delimiter))
                {
                    New-CapitalizedString $word
                }

                $tmpString = $tmpString -join $Delimiter
                Write-Verbose "Converted [$Element] to [$tmpString]"
            }
            
            $Result.Add($tmpString) | Out-Null
        }
        
    }
    
    END {$result}
}

ConvertTo-CapitalizedString.Tests.ps1

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

Describe "ConvertTo-CapitalizedString" {
    
    $TestStrings = "haha, test me","ThE wINDOWS Powershell TFM book CONTEST aNd GiVeAwAy"
    $TestString = "a aa b"

    It "should return 2 strings with all words capitalized (pipeline input)" {
        $result = $TestStrings | ConvertTo-CapitalizedString -verbose
        $result.count | Should Be 2
        $result[0] | Should BeExactly "Haha, Test Me"
        $result[1] | Should BeExactly "The Windows Powershell Tfm Book Contest And Giveaway"
    }

    It "should return 2 strings with all words capitalized" {
        $result = ConvertTo-CapitalizedString -String $TestStrings -verbose
        $result.count | Should Be 2
        $result[0] | Should BeExactly "Haha, Test Me"
        $result[1] | Should BeExactly "The Windows Powershell Tfm Book Contest And Giveaway"
    }

    It "should return 2 strings with a capital letter and the rest in lower case (pipeline input)" {
        $result = $TestStrings | ConvertTo-CapitalizedString -NoDelimiter -verbose
        $result.count | Should Be 2
        $result[0] | Should BeExactly "Haha, test me"
        $result[1] | Should BeExactly "The windows powershell tfm book contest and giveaway"
    }

    It "should return 2 strings with a capital letter and the rest in lower case" {
        $result = ConvertTo-CapitalizedString -String $TestStrings -NoDelimiter -verbose
        $result.count | Should Be 2
        $result[0] | Should BeExactly "Haha, test me"
        $result[1] | Should BeExactly "The windows powershell tfm book contest and giveaway"
    }

    It "should handle 1 character words (pipeline input)" {
        $result = $TestString|  ConvertTo-CapitalizedString -verbose
        $result.count | Should Be 1
        $result | Should BeExactly "A Aa B"
    }

    It "should handle 1 character words" {
        $result = ConvertTo-CapitalizedString $TestString -verbose
        $result.count | Should Be 1
        $result | Should BeExactly "A Aa B"
    }
}