Define exit codes as constants

src/Main.Tests.ps1

@@ -2,6 +2,9 @@ Import-Module Pester
 
 Describe "Main.ps1" {
     BeforeAll {
+        # Constants
+        "$PSScriptRoot\Set-ConstsForMain.ps1"
+
         # Target script
         $targetScript = "$PSScriptRoot\..\src\Main.ps1"
 
@@ -25,7 +28,7 @@ Describe "Main.ps1" {
             & $targetScript -listPath $listPath
 
             # Assert
-            $LASTEXITCODE | Should -Be 1
+            $LASTEXITCODE | Should -Be $EXIT_PARAM_CSV_EMPTY
         }
     }
 
@@ -40,21 +43,22 @@ Describe "Main.ps1" {
             & $targetScript -listPath $listPath
 
             # Assert
-            $LASTEXITCODE | Should -Be 1
+            $LASTEXITCODE | Should -Be $EXIT_PARAM_CSV_INVALID
         }
     }
 
     Context "When the default parent path does not exist" {
         It "Should exit with a non-zero code" {
             # Arrange
             $listPath = "$listDirPath\list.csv"
+            New-Item -Path $listPath
             $defaultParent = "$testDirPath\absent"
 
             # Act
             & $targetScript -listPath $listPath -defaultParent $defaultParent
 
             # Assert
-            $LASTEXITCODE | Should -Be 1
+            $LASTEXITCODE | Should -Be $EXIT_PARAM_PARENT_INVALID
         }
     }
 
@@ -78,7 +82,7 @@ Describe "Main.ps1" {
             & $targetScript -listPath $listPath -defaultParent $defaultParent
 
             # Assert
-            $LASTEXITCODE | Should -Be 0
+            $LASTEXITCODE | Should -Be $EXIT_SUCCESS
             $shortcutPath = "$parent\$name.lnk"
             $shortcutPath | Should -Not -Exist
         }
@@ -105,7 +109,7 @@ Describe "Main.ps1" {
             & $targetScript -listPath $listPath -defaultParent $defaultParent
 
             # Assert
-            $LASTEXITCODE | Should -Be 0
+            $LASTEXITCODE | Should -Be $EXIT_SUCCESS
             $shortcutPath = "$parent\$name.lnk"
             $shortcutPath | Should -Exist
         }

src/Main.ps1

@@ -4,6 +4,9 @@ param (
     [string]$defaultParent = ".\"
 )
 
+# Constants
+"$PSScriptRoot\Set-ConstsForMain.ps1"
+
 # Dot sourcing
 . "$PSScriptRoot\New-Shortcut.ps1"
 . "$PSScriptRoot\Set-RegexEnvVars.ps1"
@@ -13,21 +16,21 @@ param (
 if ([string]::IsNullOrEmpty($listPath)) {
     # Display an error message and exit with a non-zero code
     Write-Host "Error: CSV file parameter is empty"
-    exit 1
+    exit $EXIT_PARAM_CSV_EMPTY
 }
 
 # Check if the list path is invalid
 if (!(Test-Path $listPath)) {
     # Display an error message and exit with a non-zero code
     Write-Host "Error: $listPath does not exist"
-    exit 1
+    exit $EXIT_PARAM_CSV_INVALID
 }
 
 # Check if the default parent path is invalid
 if (!(Test-Path $defaultParent)) {
     # Display an error message and exit with a non-zero code
     Write-Host "Error: $defaultParent does not exist"
-    exit 1
+    exit $EXIT_PARAM_PARENT_INVALID
 }
 
 # Get listed paths
@@ -78,4 +81,4 @@ foreach ($line in $data) {
 }
 
 # Exit with a success code
-exit 0
+exit $EXIT_SUCCESS

src/Set-ConstsForMain.ps1

@@ -0,0 +1,5 @@
+# Define exit codes
+Set-Variable -Name EXIT_SUCCESS -Value 0 -Option constant
+Set-Variable -Name EXIT_PARAM_CSV_EMPTY -Value 1 -Option constant
+Set-Variable -Name EXIT_PARAM_CSV_INVALID -Value 2 -Option constant
+Set-Variable -Name EXIT_PARAM_PARENT_INVALID -Value 3 -Option Constant