diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 0c3fb1d..2fbc339 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -194,6 +194,15 @@ jobs:
             exit 1
           }
 
+      - name: Run GUI config logic tests
+        shell: pwsh
+        run: |
+          $result = Invoke-Pester -Path "Tests/Unit/Test-GuiConfigLogic.ps1" -Output Detailed -PassThru
+          if ($result.FailedCount -gt 0) {
+            Write-Error "$($result.FailedCount) test(s) failed in Test-GuiConfigLogic.ps1"
+            exit 1
+          }
+
       - name: Run Store search suggestion tests
         shell: pwsh
         run: |
diff --git a/Tests/Unit/Test-GuiConfigLogic.ps1 b/Tests/Unit/Test-GuiConfigLogic.ps1
new file mode 100644
index 0000000..7d990f2
--- /dev/null
+++ b/Tests/Unit/Test-GuiConfigLogic.ps1
@@ -0,0 +1,108 @@
+#Requires -Modules Pester
+<#
+.SYNOPSIS
+    Unit tests for the pure config import/export and deployment-summary logic.
+.DESCRIPTION
+    Show-ConfigWindow.ps1 and MainWindow-Deployment.ps1 mix WPF dialog code with
+    functions that only shape data: which categories a saved config offers, the
+    human-readable deployment summary, the category detail strings, and parsing
+    the saved app list. Those are covered here.
+
+    The files declare WPF types on other functions' parameters, but PowerShell
+    resolves those at call time, so the files dot-source and the pure functions
+    run without WPF loaded and without a UI thread. Only the pure functions are
+    called here.
+#>
+
+BeforeAll {
+    $repoRoot = Resolve-Path (Join-Path $PSScriptRoot '..\..') | Select-Object -ExpandProperty Path
+    . (Join-Path $repoRoot 'Scripts\GUI\Show-ConfigWindow.ps1')
+    . (Join-Path $repoRoot 'Scripts\GUI\MainWindow-Deployment.ps1')
+}
+
+Describe 'Get-AvailableImportExportCategories' {
+    It 'lists only the sections the config actually contains' {
+        Get-AvailableImportExportCategories -Config ([PSCustomObject]@{ Apps = @('x') }) | Should -Be @('Applications')
+        Get-AvailableImportExportCategories -Config ([PSCustomObject]@{ Tweaks = @('x') }) | Should -Be @('System Tweaks')
+        Get-AvailableImportExportCategories -Config ([PSCustomObject]@{ Deployment = @{} }) | Should -Be @('Deployment Settings')
+    }
+
+    It 'lists all three in order when all are present' {
+        $config = [PSCustomObject]@{ Apps = @('x'); Tweaks = @('y'); Deployment = @{} }
+        Get-AvailableImportExportCategories -Config $config | Should -Be @('Applications', 'System Tweaks', 'Deployment Settings')
+    }
+
+    It 'lists nothing for an empty config' {
+        @(Get-AvailableImportExportCategories -Config ([PSCustomObject]@{})).Count | Should -Be 0
+    }
+}
+
+Describe 'Get-DeploymentCategoryDetailString' {
+    It 'describes each user selection' {
+        Get-DeploymentCategoryDetailString -DeploymentSettings @(@{ Name = 'UserSelectionIndex'; Value = 0 }) | Should -Be 'User: Current User'
+        Get-DeploymentCategoryDetailString -DeploymentSettings @(@{ Name = 'UserSelectionIndex'; Value = 2 }) | Should -Be 'User: Sysprep'
+    }
+
+    It 'names the other user when one is given, and falls back when not' {
+        Get-DeploymentCategoryDetailString -DeploymentSettings @(
+            @{ Name = 'UserSelectionIndex'; Value = 1 }, @{ Name = 'OtherUsername'; Value = 'Jeff' }
+        ) | Should -Be 'User: Jeff'
+        Get-DeploymentCategoryDetailString -DeploymentSettings @(@{ Name = 'UserSelectionIndex'; Value = 1 }) | Should -Be 'User: Other User'
+    }
+
+    It 'puts user/scope on one line and options on the next' {
+        $result = Get-DeploymentCategoryDetailString -DeploymentSettings @(
+            @{ Name = 'UserSelectionIndex'; Value = 0 },
+            @{ Name = 'AppRemovalScopeIndex'; Value = 0 },
+            @{ Name = 'CreateRestorePoint'; Value = $true },
+            @{ Name = 'RestartExplorer'; Value = $true }
+        )
+        $result | Should -Be "User: Current User, App Removal: All Users`nOptions: Restore Point, Restart Explorer"
+    }
+
+    It 'omits an option that is present but false' {
+        $result = Get-DeploymentCategoryDetailString -DeploymentSettings @(
+            @{ Name = 'CreateRestorePoint'; Value = $true },
+            @{ Name = 'RestartExplorer'; Value = $false }
+        )
+        $result | Should -Be 'Options: Restore Point'
+    }
+
+    It 'falls back to a default line when nothing is set' {
+        Get-DeploymentCategoryDetailString -DeploymentSettings @() | Should -Be 'Default deployment settings'
+    }
+}
+
+Describe 'Build-CategoryDetails' {
+    It 'pluralizes app and tweak counts and handles zero' {
+        (Build-CategoryDetails -AppCount 0 -TweakCount 0)['Applications'] | Should -Be 'No apps selected'
+        (Build-CategoryDetails -AppCount 1 -TweakCount 0)['Applications'] | Should -Be '1 app selected'
+        (Build-CategoryDetails -AppCount 3 -TweakCount 0)['Applications'] | Should -Be '3 apps selected'
+        (Build-CategoryDetails -AppCount 0 -TweakCount 1)['System Tweaks'] | Should -Be '1 tweak selected'
+        (Build-CategoryDetails -AppCount 0 -TweakCount 5)['System Tweaks'] | Should -Be '5 tweaks selected'
+    }
+
+    It 'includes the deployment summary only when deployment settings are given' {
+        (Build-CategoryDetails -AppCount 1 -TweakCount 1).ContainsKey('Deployment Settings') | Should -BeFalse
+        $withDeploy = Build-CategoryDetails -AppCount 1 -TweakCount 1 -DeploymentSettings @(@{ Name = 'UserSelectionIndex'; Value = 2 })
+        $withDeploy['Deployment Settings'] | Should -Be 'User: Sysprep'
+    }
+}
+
+Describe 'Get-SavedAppIdsFromSettingsJson' {
+    It 'parses a comma-separated string, trimming and dropping empties' {
+        $json = [PSCustomObject]@{ Settings = @(@{ Name = 'Apps'; Value = 'App.One, App.Two ,, App.Three' }) }
+        Get-SavedAppIdsFromSettingsJson -SettingsJson $json | Should -Be @('App.One', 'App.Two', 'App.Three')
+    }
+
+    It 'accepts an array value' {
+        $json = [PSCustomObject]@{ Settings = @(@{ Name = 'Apps'; Value = @('App.One', 'App.Two') }) }
+        Get-SavedAppIdsFromSettingsJson -SettingsJson $json | Should -Be @('App.One', 'App.Two')
+    }
+
+    It 'returns nothing when there is no Apps setting or no value' {
+        Get-SavedAppIdsFromSettingsJson -SettingsJson ([PSCustomObject]@{ Settings = @(@{ Name = 'DisableTelemetry'; Value = $true }) }) | Should -BeNullOrEmpty
+        Get-SavedAppIdsFromSettingsJson -SettingsJson ([PSCustomObject]@{ Settings = @(@{ Name = 'Apps'; Value = '' }) }) | Should -BeNullOrEmpty
+        Get-SavedAppIdsFromSettingsJson -SettingsJson ([PSCustomObject]@{}) | Should -BeNullOrEmpty
+    }
+}