diff --git a/CHANGELOG.md b/CHANGELOG.md
index f6d17d8..33df562 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,9 @@
 - Refactor Test-TargetResource to return $false in all DSC resource - Fixes
   [Issue #12](https://github.com/PlagueHO/FileContentDsc/issues/13).
 - Correct configuration names in Examples - fixes [Issue #15](https://github.com/PowerShell/FileContentDsc/issues/15).
+- Refactor Test/Set-TargetResource in ReplaceText to be able to add a key if it
+  doesn't exist but should -Fixes
+  [Issue#20](https://github.com/PlagueHO/FileContentDsc/issues/20).
 
 ## 1.0.0.0
 
diff --git a/DSCResources/DSR_ReplaceText/DSR_ReplaceText.psm1 b/DSCResources/DSR_ReplaceText/DSR_ReplaceText.psm1
index e39958d..96d6e90 100644
--- a/DSCResources/DSR_ReplaceText/DSR_ReplaceText.psm1
+++ b/DSCResources/DSR_ReplaceText/DSR_ReplaceText.psm1
@@ -103,6 +103,9 @@ function Get-TargetResource
     .PARAMETER Secret
         The secret text to replace the text identified by the RegEx.
         Only used when Type is set to 'Secret'.
+
+    .PARAMETER AllowAppend
+        Specifies to append text to the file being modified. Adds the ability to add a configuration entry.
 #>
 function Set-TargetResource
 {
@@ -133,7 +136,11 @@ function Set-TargetResource
         [Parameter()]
         [System.Management.Automation.PSCredential]
         [System.Management.Automation.Credential()]
-        $Secret
+        $Secret,
+
+        [Parameter()]
+        [System.Boolean]
+        $AllowAppend = $false
     )
 
     Assert-ParametersValid @PSBoundParameters
@@ -155,10 +162,17 @@ function Set-TargetResource
 
     if ($null -eq $fileContent)
     {
+        # Configuration file does not exist
         $fileContent = $Text
     }
+    elseif ([regex]::Matches($fileContent, $Search).Count -eq 0 -and $AllowAppend -eq $true)
+    {
+        # Configuration file exists but Text does not exist so lets add it
+        $fileContent = Add-ConfigurationEntry -FileContent $fileContent -Text $Text
+    }
     else
     {
+        # Configuration file exists but Text not in a desired state so lets update it
         $fileContent = $fileContent -Replace $Search, $Text
     }
 
@@ -189,6 +203,9 @@ function Set-TargetResource
     .PARAMETER Secret
         The secret text to replace the text identified by the RegEx.
         Only used when Type is set to 'Secret'.
+
+    .PARAMETER AllowAppend
+        Specifies to append text to the file being modified. Adds the ability to add a configuration entry.
 #>
 function Test-TargetResource
 {
@@ -218,7 +235,11 @@ function Test-TargetResource
         [Parameter()]
         [System.Management.Automation.PSCredential]
         [System.Management.Automation.Credential()]
-        $Secret
+        $Secret,
+
+        [Parameter()]
+        [System.Boolean]
+        $AllowAppend = $false
     )
 
     Assert-ParametersValid @PSBoundParameters
@@ -239,6 +260,15 @@ function Test-TargetResource
 
     if ($results.Count -eq 0)
     {
+        if ($AllowAppend -eq $true)
+        {
+            # No matches found - but we want to append
+            Write-Verbose -Message ($localizedData.StringNotFoundMessageAppend -f `
+                    $Path, $Search)
+
+            return $false
+        }
+
         # No matches found - already in state
         Write-Verbose -Message ($localizedData.StringNotFoundMessage -f `
                 $Path, $Search)
@@ -325,7 +355,11 @@ function Assert-ParametersValid
         [Parameter()]
         [System.Management.Automation.PSCredential]
         [System.Management.Automation.Credential()]
-        $Secret
+        $Secret,
+
+        [Parameter()]
+        [System.Boolean]
+        $AllowAppend = $false
     )
 
     # Does the file's parent path exist?
@@ -338,4 +372,49 @@ function Assert-ParametersValid
     } # if
 }
 
+<#
+    .SYNOPSIS
+        Uses the stringBuilder class to append a configuration entry to the existing file content.
+
+    .PARAMETER FileContent
+        The existing file content of the configuration file.
+
+    .PARAMETER Text
+        The text to append to the end of the FileContent.
+#>
+function Add-ConfigurationEntry
+{
+    [OutputType([String])]
+    [CmdletBinding()]
+    param
+    (
+        [Parameter(Mandatory = $true)]
+        [String]
+        $FileContent,
+
+        [Parameter(Mandatory = $true)]
+        [String]
+        $Text
+    )
+
+    if ($FileContent -match '\n$' -and $FileContent -notmatch '\r\n$')
+    {
+        # default *nix line ending
+        $detectedNewLineFormat = "`n"
+    }
+    else
+    {
+        # default Windows line ending
+        $detectedNewLineFormat = "`r`n"
+    }
+
+    $stringBuilder = New-Object -TypeName System.Text.StringBuilder
+
+    $null = $stringBuilder.Append($FileContent)
+    $null = $stringBuilder.Append($Text)
+    $null = $stringBuilder.Append($detectedNewLineFormat)
+
+    return $stringBuilder.ToString()
+}
+
 Export-ModuleMember -Function *-TargetResource
diff --git a/DSCResources/DSR_ReplaceText/DSR_ReplaceText.schema.mof b/DSCResources/DSR_ReplaceText/DSR_ReplaceText.schema.mof
index 7b37409..c30aaa4 100644
--- a/DSCResources/DSR_ReplaceText/DSR_ReplaceText.schema.mof
+++ b/DSCResources/DSR_ReplaceText/DSR_ReplaceText.schema.mof
@@ -5,5 +5,6 @@ class DSR_ReplaceText : OMI_BaseResource
   [Key, Description("The RegEx string to use to search the text file.")] String Search;
   [Write, Description("Specifies the value type to use as the replacement string. Defaults to 'Text'."),ValueMap{"Text", "Secret"},Values{"Text", "Secret"}] String Type;
   [Write, Description("The text to replace the text identified by the RegEx. Only used when Type is set to 'Text'.")] String Text;
-  [write, Description("The secret text to replace the text identified by the RegEx. Only used when Type is set to 'Secret'."),EmbeddedInstance("MSFT_Credential")] String Secret;
+  [Write, Description("The secret text to replace the text identified by the RegEx. Only used when Type is set to 'Secret'."),EmbeddedInstance("MSFT_Credential")] String Secret;
+  [Write, Description("Specifies to append text to the file being modified. Adds the ability to add a configuration entry.")] Boolean AllowAppend;
 };
diff --git a/DSCResources/DSR_ReplaceText/en-US/DSR_ReplaceText.strings.psd1 b/DSCResources/DSR_ReplaceText/en-US/DSR_ReplaceText.strings.psd1
index 85dca92..98ee192 100644
--- a/DSCResources/DSR_ReplaceText/en-US/DSR_ReplaceText.strings.psd1
+++ b/DSCResources/DSR_ReplaceText/en-US/DSR_ReplaceText.strings.psd1
@@ -2,6 +2,7 @@
 
 ConvertFrom-StringData @'
     SearchForTextMessage = Searching using RegEx '{1}' in file '{0}'.
+    StringNotFoundMessageAppend = String not found using RegEx '{1}' in file '{0}', change required.
     StringNotFoundMessage = String not found using RegEx '{1}' in file '{0}', change not required.
     StringMatchFoundMessage = String(s) '{2}' found using RegEx '{1}' in file '{0}'.
     StringReplacementRequiredMessage = String found using RegEx '{1}' in file '{0}', replacement required.
diff --git a/TestFile.txt b/TestFile.txt
new file mode 100644
index 0000000..2d9e0de
--- /dev/null
+++ b/TestFile.txt
@@ -0,0 +1,25 @@
+Setting1=Value1
+Setting.Two='Value2'
+Setting.Two='Value3'
+Setting.Two='TestText'
+Setting3.Test=Value4
+
+Setting.NotExist='TestText'Setting1=Value1
+Setting.Two='Value2'
+Setting.Two='Value3'
+Setting.Two='TestText'
+Setting3.Test=Value4
+
+Setting.NotExist='TestText'Setting1=Value1
+Setting.Two='Value2'
+Setting.Two='Value3'
+Setting.Two='TestText'
+Setting3.Test=Value4
+
+Setting.NotExist='TestText'Setting1=Value1
+Setting.Two='Value2'
+Setting.Two='Value3'
+Setting.Two='TestText'
+Setting3.Test=Value4
+
+Setting.NotExist='TestText'
\ No newline at end of file
diff --git a/Tests/Unit/DSR_ReplaceText.Tests.ps1 b/Tests/Unit/DSR_ReplaceText.Tests.ps1
index b993dee..cd8c723 100644
--- a/Tests/Unit/DSR_ReplaceText.Tests.ps1
+++ b/Tests/Unit/DSR_ReplaceText.Tests.ps1
@@ -36,6 +36,7 @@ try
         $script:testSecret = 'TestSecret'
         $script:testSearch = "Setting\.Two='(.)*'"
         $script:testSearchNoFind = "Setting.NotExist='(.)*'"
+        $script:testTextReplaceNoFind = "Setting.NotExist='$($script:testText)'"
         $script:testTextReplace = "Setting.Two='$($script:testText)'"
         $script:testSecretReplace = "Setting.Two='$($script:testSecret)'"
         $script:testSecureSecretReplace = ConvertTo-SecureString -String $script:testSecretReplace -AsPlainText -Force
@@ -57,6 +58,16 @@ Setting.Two='$($script:testText)'
 Setting.Two='$($script:testText)'
 Setting3.Test=Value4
 
+"@
+
+        $script:testFileExpectedTextContentNewKey = @"
+Setting1=Value1
+Setting.Two='Value2'
+Setting.Two='Value3'
+Setting.Two='$($script:testText)'
+Setting3.Test=Value4
+Setting.NotExist='$($script:testText)'
+
 "@
 
         $script:testFileExpectedSecretContent = @"
@@ -88,9 +99,9 @@ Setting3.Test=Value4
 
                 It 'Should not throw an exception' {
                     { $script:result = Get-TargetResource `
-                        -Path $script:testTextFile `
-                        -Search $script:testSearch `
-                        -Verbose
+                            -Path $script:testTextFile `
+                            -Search $script:testSearch `
+                            -Verbose
                     } | Should -Not -Throw
                 }
 
@@ -129,9 +140,9 @@ Setting3.Test=Value4
 
                 It 'Should not throw an exception' {
                     { $script:result = Get-TargetResource `
-                        -Path $script:testTextFile `
-                        -Search $script:testSearchNoFind `
-                        -Verbose
+                            -Path $script:testTextFile `
+                            -Search $script:testSearchNoFind `
+                            -Verbose
                     } | Should -Not -Throw
                 }
 
@@ -173,17 +184,67 @@ Setting3.Test=Value4
                 Mock `
                     -CommandName Set-Content `
                     -ParameterFilter {
+                    ($path -eq $script:testTextFile) -and `
+                    ($value -eq $script:testFileExpectedTextContent)
+                } `
+                    -Verifiable
+
+                It 'Should not throw an exception' {
+                    { Set-TargetResource `
+                            -Path $script:testTextFile `
+                            -Search $script:testSearch `
+                            -Text $script:testTextReplace `
+                            -Verbose
+                    } | Should -Not -Throw
+                }
+
+                It 'Should call the expected mocks' {
+                    Assert-VerifiableMock
+                    Assert-MockCalled -CommandName Assert-ParametersValid -Exactly 1
+
+                    Assert-MockCalled `
+                        -CommandName Get-Content `
+                        -ParameterFilter { $path -eq $script:testTextFile } `
+                        -Exactly 1
+
+                    Assert-MockCalled `
+                        -CommandName Set-Content `
+                        -ParameterFilter {
                         ($path -eq $script:testTextFile) -and `
                         ($value -eq $script:testFileExpectedTextContent)
                     } `
+                        -Exactly 1
+                }
+            }
+
+            Context 'File exists search text can not be found and AllowAppend is TRUE' {
+                # verifiable (should be called) mocks
+                Mock `
+                    -CommandName Assert-ParametersValid `
+                    -ModuleName 'DSR_ReplaceText' `
+                    -Verifiable
+
+                Mock `
+                    -CommandName Get-Content `
+                    -ParameterFilter { $path -eq $script:testTextFile } `
+                    -MockWith { $script:testFileContent } `
+                    -Verifiable
+
+                Mock `
+                    -CommandName Set-Content `
+                    -ParameterFilter {
+                    ($path -eq $script:testTextFile) -and `
+                    ($value -eq $script:testFileExpectedTextContentNewKey)
+                } `
                     -Verifiable
 
                 It 'Should not throw an exception' {
-                    { Set-TargetResource `
-                        -Path $script:testTextFile `
-                        -Search $script:testSearch `
-                        -Text $script:testTextReplace `
-                        -Verbose
+                    { $script:result = Set-TargetResource `
+                            -Path $script:testTextFile `
+                            -Search $script:testSearchNoFind `
+                            -Text $script:testTextReplaceNoFind `
+                            -AllowAppend $true `
+                            -Verbose
                     } | Should -Not -Throw
                 }
 
@@ -199,15 +260,14 @@ Setting3.Test=Value4
                     Assert-MockCalled `
                         -CommandName Set-Content `
                         -ParameterFilter {
-                            ($path -eq $script:testTextFile) -and `
-                            ($value -eq $script:testFileExpectedTextContent)
-                        } `
+                        ($path -eq $script:testTextFile) -and `
+                        ($value -eq $script:testFileExpectedTextContentNewKey)
+                    } `
                         -Exactly 1
                 }
             }
 
-            Context 'File exists and search secret can be found' {
-                # verifiable (should be called) mocks
+            Context 'File exists search text can not be found and AllowAppend is FALSE' {
                 Mock `
                     -CommandName Assert-ParametersValid `
                     -ModuleName 'DSR_ReplaceText' `
@@ -222,18 +282,68 @@ Setting3.Test=Value4
                 Mock `
                     -CommandName Set-Content `
                     -ParameterFilter {
+                    ($path -eq $script:testTextFile) -and `
+                    ($value -eq $script:testFileContent)
+                } `
+                    -Verifiable
+
+                It 'Should not throw an exception' {
+                    { $script:result = Set-TargetResource `
+                            -Path $script:testTextFile `
+                            -Search $script:testSearchNoFind `
+                            -Text $script:testTextReplaceNoFind `
+                            -AllowAppend $false `
+                            -Verbose
+                    } | Should -Not -Throw
+                }
+
+                It 'Should call the expected mocks' {
+                    Assert-VerifiableMock
+                    Assert-MockCalled -CommandName Assert-ParametersValid -Exactly 1
+
+                    Assert-MockCalled `
+                        -CommandName Get-Content `
+                        -ParameterFilter { $path -eq $script:testTextFile } `
+                        -Exactly 1
+
+                    Assert-MockCalled `
+                        -CommandName Set-Content `
+                        -ParameterFilter {
                         ($path -eq $script:testTextFile) -and `
-                        ($value -eq $script:testFileExpectedSecretContent)
+                        ($value -eq $script:testFileContent)
                     } `
+                        -Exactly 1
+                }
+            }
+
+            Context 'File exists and search secret can be found' {
+                # verifiable (should be called) mocks
+                Mock `
+                    -CommandName Assert-ParametersValid `
+                    -ModuleName 'DSR_ReplaceText' `
+                    -Verifiable
+
+                Mock `
+                    -CommandName Get-Content `
+                    -ParameterFilter { $path -eq $script:testTextFile } `
+                    -MockWith { $script:testFileContent } `
+                    -Verifiable
+
+                Mock `
+                    -CommandName Set-Content `
+                    -ParameterFilter {
+                    ($path -eq $script:testTextFile) -and `
+                    ($value -eq $script:testFileExpectedSecretContent)
+                } `
                     -Verifiable
 
                 It 'Should not throw an exception' {
                     { Set-TargetResource `
-                        -Path $script:testTextFile `
-                        -Search $script:testSearch `
-                        -Type 'Secret' `
-                        -Secret $script:testSecretCredential `
-                        -Verbose
+                            -Path $script:testTextFile `
+                            -Search $script:testSearch `
+                            -Type 'Secret' `
+                            -Secret $script:testSecretCredential `
+                            -Verbose
                     } | Should -Not -Throw
                 }
 
@@ -249,9 +359,9 @@ Setting3.Test=Value4
                     Assert-MockCalled `
                         -CommandName Set-Content `
                         -ParameterFilter {
-                            ($path -eq $script:testTextFile) -and `
-                            ($value -eq $script:testFileExpectedSecretContent)
-                        } `
+                        ($path -eq $script:testTextFile) -and `
+                        ($value -eq $script:testFileExpectedSecretContent)
+                    } `
                         -Exactly 1
                 }
             }
@@ -272,17 +382,17 @@ Setting3.Test=Value4
                 Mock `
                     -CommandName Set-Content `
                     -ParameterFilter {
-                        ($path -eq $script:testTextFile) -and `
-                        ($value -eq $script:testTextReplace)
-                    } `
+                    ($path -eq $script:testTextFile) -and `
+                    ($value -eq $script:testTextReplace)
+                } `
                     -Verifiable
 
                 It 'Should not throw an exception' {
                     { Set-TargetResource `
-                        -Path $script:testTextFile `
-                        -Search $script:testSearch `
-                        -Text $script:testTextReplace `
-                        -Verbose
+                            -Path $script:testTextFile `
+                            -Search $script:testSearch `
+                            -Text $script:testTextReplace `
+                            -Verbose
                     } | Should -Not -Throw
                 }
 
@@ -298,9 +408,9 @@ Setting3.Test=Value4
                     Assert-MockCalled `
                         -CommandName Set-Content `
                         -ParameterFilter {
-                            ($path -eq $script:testTextFile) -and `
-                            ($value -eq $script:testTextReplace)
-                        } `
+                        ($path -eq $script:testTextFile) -and `
+                        ($value -eq $script:testTextReplace)
+                    } `
                         -Exactly 1
                 }
             }
@@ -310,7 +420,7 @@ Setting3.Test=Value4
 
         #region Function Test-TargetResource
         Describe 'DSR_ReplaceString\Test-TargetResource' {
-            Context 'File exists and search text can not be found' {
+            Context 'File exists search text can not be found and AllowAppend is TRUE' {
                 # verifiable (should be called) mocks
                 Mock `
                     -CommandName Assert-ParametersValid `
@@ -333,14 +443,61 @@ Setting3.Test=Value4
 
                 It 'Should not throw an exception' {
                     { $script:result = Test-TargetResource `
-                        -Path $script:testTextFile `
-                        -Search $script:testSearchNoFind `
-                        -Text $script:testTextReplace `
-                        -Verbose
+                            -Path $script:testTextFile `
+                            -Search $script:testSearchNoFind `
+                            -Text $script:testTextReplace `
+                            -AllowAppend $true `
+                            -Verbose
                     } | Should -Not -Throw
                 }
 
-                It 'Should return true' {
+                It 'Should return false' {
+                    $script:result | Should -Be $false
+                }
+
+                It 'Should call the expected mocks' {
+                    Assert-VerifiableMock
+                    Assert-MockCalled -CommandName Assert-ParametersValid -Exactly 1
+
+                    Assert-MockCalled `
+                        -CommandName Get-Content `
+                        -ParameterFilter { $path -eq $script:testTextFile } `
+                        -Exactly 1
+                }
+            }
+
+            Context 'File exists search text can not be found and AllowAppend is FALSE' {
+                # verifiable (should be called) mocks
+                Mock `
+                    -CommandName Assert-ParametersValid `
+                    -ModuleName 'DSR_ReplaceText' `
+                    -Verifiable
+
+                Mock `
+                    -CommandName Test-Path `
+                    -ModuleName 'DSR_ReplaceText' `
+                    -MockWith { $true } `
+                    -Verifiable
+
+                Mock `
+                    -CommandName Get-Content `
+                    -ParameterFilter { $path -eq $script:testTextFile } `
+                    -MockWith { $script:testFileContent } `
+                    -Verifiable
+
+                $script:result = $null
+
+                It 'Should not throw an exception' {
+                    { $script:result = Test-TargetResource `
+                            -Path $script:testTextFile `
+                            -Search $script:testSearchNoFind `
+                            -Text $script:testTextReplace `
+                            -AllowAppend $false `
+                            -Verbose
+                    } | Should -Not -Throw
+                }
+
+                It 'Should return false' {
                     $script:result | Should -Be $true
                 }
 
@@ -355,6 +512,7 @@ Setting3.Test=Value4
                 }
             }
 
+
             Context 'File exists and search text can be found but does not match replace string' {
                 # verifiable (should be called) mocks
                 Mock `
@@ -378,10 +536,10 @@ Setting3.Test=Value4
 
                 It 'Should not throw an exception' {
                     { $script:result = Test-TargetResource `
-                        -Path $script:testTextFile `
-                        -Search $script:testSearch `
-                        -Text $script:testTextReplace `
-                        -Verbose
+                            -Path $script:testTextFile `
+                            -Search $script:testSearch `
+                            -Text $script:testTextReplace `
+                            -Verbose
                     } | Should -Not -Throw
                 }
 
@@ -423,10 +581,10 @@ Setting3.Test=Value4
 
                 It 'Should not throw an exception' {
                     { $script:result = Test-TargetResource `
-                        -Path $script:testTextFile `
-                        -Search $script:testSearch `
-                        -Text $script:testTextReplace `
-                        -Verbose
+                            -Path $script:testTextFile `
+                            -Search $script:testSearch `
+                            -Text $script:testTextReplace `
+                            -Verbose
                     } | Should -Not -Throw
                 }
 
@@ -468,11 +626,11 @@ Setting3.Test=Value4
 
                 It 'Should not throw an exception' {
                     { $script:result = Test-TargetResource `
-                        -Path $script:testTextFile `
-                        -Search $script:testSearch `
-                        -Type 'Secret' `
-                        -Secret $script:testSecretCredential `
-                        -Verbose
+                            -Path $script:testTextFile `
+                            -Search $script:testSearch `
+                            -Type 'Secret' `
+                            -Secret $script:testSecretCredential `
+                            -Verbose
                     } | Should -Not -Throw
                 }
 
@@ -514,11 +672,11 @@ Setting3.Test=Value4
 
                 It 'Should not throw an exception' {
                     { $script:result = Test-TargetResource `
-                        -Path $script:testTextFile `
-                        -Search $script:testSearch `
-                        -Type 'Secret' `
-                        -Secret $script:testSecretCredential `
-                        -Verbose
+                            -Path $script:testTextFile `
+                            -Search $script:testSearch `
+                            -Type 'Secret' `
+                            -Secret $script:testSecretCredential `
+                            -Verbose
                     } | Should -Not -Throw
                 }
 
@@ -559,10 +717,10 @@ Setting3.Test=Value4
 
                 It 'Should not throw an exception' {
                     { $script:result = Test-TargetResource `
-                        -Path $script:testTextFile `
-                        -Search $script:testSearchNoFind `
-                        -Text $script:testTextReplace `
-                        -Verbose
+                            -Path $script:testTextFile `
+                            -Search $script:testSearchNoFind `
+                            -Text $script:testTextReplace `
+                            -Verbose
                     } | Should -Not -Throw
                 }
 
@@ -600,9 +758,9 @@ Setting3.Test=Value4
 
                 It 'Should not throw an exception' {
                     { Assert-ParametersValid `
-                        -Path $script:testTextFile `
-                        -Search $script:testSearch `
-                        -Verbose
+                            -Path $script:testTextFile `
+                            -Search $script:testSearch `
+                            -Verbose
                     } | Should -Not -Throw
                 }
 
@@ -632,9 +790,9 @@ Setting3.Test=Value4
 
                 It 'Should throw expected exception' {
                     { Assert-ParametersValid `
-                        -Path $script:testTextFile `
-                        -Search $script:testSearch `
-                        -Verbose
+                            -Path $script:testTextFile `
+                            -Search $script:testSearch `
+                            -Verbose
                     } | Should -Throw $errorRecord
                 }
 
@@ -645,6 +803,44 @@ Setting3.Test=Value4
             }
         }
         #endregion
+
+        Describe 'DSR_ReplaceText\Add-ConfigurationEntry' {
+            Context 'Append text' {
+                $result = Add-ConfigurationEntry `
+                    -Text "Setting.NotExist='$($script:testText)'" `
+                    -FileContent $script:testFileContent
+
+                It 'Should append line to end of text' {
+                    $result | Should -Be $script:testFileExpectedTextContentNewKey
+                }
+            }
+
+            Context 'Apply a LF (default *nix)' {
+                $nixString = "Line1`nLine2`n"
+
+                $result = Add-ConfigurationEntry `
+                    -Text 'Line3' `
+                    -FileContent $nixString
+
+                It 'Should end with a LF' {
+                    $result -match '\n$'     | Should -BeTrue
+                    $result -match '\b\r\n$' | Should -BeFalse
+                }
+            }
+
+            Context 'Apply a CRLF (default Windows)' {
+                $windowsString = "Line1`r`nLine2`r`n"
+
+                $result = Add-ConfigurationEntry `
+                    -Text 'Line3' `
+                    -FileContent $windowsString
+
+                It 'Should match a CRLF line ending' {
+                    $result -match '\r\n$' | Should -BeTrue
+                    $result -match '\b\n$' | Should -BeFalse
+                }
+            }
+        }
     }
 }
 finally