diff --git a/authoring-ui.Tests/Covenant.Setup.Authoring.Tests.csproj b/authoring-ui.Tests/Covenant.Setup.Authoring.Tests.csproj
new file mode 100644
index 0000000..c495156
--- /dev/null
+++ b/authoring-ui.Tests/Covenant.Setup.Authoring.Tests.csproj
@@ -0,0 +1,23 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net10.0-windows10.0.19041.0</TargetFramework>
+    <Nullable>enable</Nullable>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <IsPackable>false</IsPackable>
+    <IsTestProject>true</IsTestProject>
+    <AssemblyName>Covenant.Setup.Authoring.Tests</AssemblyName>
+    <RootNamespace>Covenant.Setup.Authoring.Tests</RootNamespace>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.11.1" />
+    <PackageReference Include="xunit" Version="2.9.2" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.8.2" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\authoring-ui\Covenant.Setup.Authoring.csproj" />
+  </ItemGroup>
+
+</Project>
diff --git a/authoring-ui.Tests/CovenantSetupToolTests.cs b/authoring-ui.Tests/CovenantSetupToolTests.cs
new file mode 100644
index 0000000..16802a3
--- /dev/null
+++ b/authoring-ui.Tests/CovenantSetupToolTests.cs
@@ -0,0 +1,86 @@
+using Covenant.Setup.Authoring;
+using Xunit;
+
+namespace Covenant.Setup.Authoring.Tests;
+
+public class CovenantSetupToolTests
+{
+    [Fact]
+    public void Find_returns_first_existing_covenant_setup_exe()
+    {
+        using var temp = new TempDirectory();
+        var missing = Path.Combine(temp.Path, "missing");
+        var found = Path.Combine(temp.Path, "found");
+        Directory.CreateDirectory(missing);
+        Directory.CreateDirectory(found);
+        var exe = Path.Combine(found, "covenant-setup.exe");
+        File.WriteAllText(exe, string.Empty);
+
+        var tool = CovenantSetupToolLocator.Find([missing, found]);
+
+        Assert.NotNull(tool);
+        Assert.Equal(exe, tool.Path);
+    }
+
+    [Fact]
+    public void Find_returns_null_when_no_candidate_contains_exe()
+    {
+        using var temp = new TempDirectory();
+        var candidate = Path.Combine(temp.Path, "candidate");
+        Directory.CreateDirectory(candidate);
+
+        var tool = CovenantSetupToolLocator.Find([candidate]);
+
+        Assert.Null(tool);
+    }
+
+    [Fact]
+    public void CreateStartInfo_builds_expected_package_command()
+    {
+        var tool = new CovenantSetupTool(@"C:\tools\covenant-setup.exe");
+        var manifest = @"C:\src\sample app\install.toml";
+        var output = @"C:\out dir";
+
+        var startInfo = CovenantSetupPackager.CreateStartInfo(tool, manifest, output);
+
+        Assert.Equal(tool.Path, startInfo.FileName);
+        Assert.Equal(@"C:\src\sample app", startInfo.WorkingDirectory);
+        Assert.False(startInfo.UseShellExecute);
+        Assert.True(startInfo.CreateNoWindow);
+        Assert.True(startInfo.RedirectStandardOutput);
+        Assert.True(startInfo.RedirectStandardError);
+        Assert.Equal(["--json", "package", manifest, "--output", output], startInfo.ArgumentList);
+    }
+
+    [Fact]
+    public void CreateStartInfo_uses_current_directory_for_relative_manifest()
+    {
+        var tool = new CovenantSetupTool(@"C:\tools\covenant-setup.exe");
+
+        var startInfo = CovenantSetupPackager.CreateStartInfo(tool, "install.toml", "dist");
+
+        Assert.Equal(Environment.CurrentDirectory, startInfo.WorkingDirectory);
+    }
+}
+
+internal sealed class TempDirectory : IDisposable
+{
+    public TempDirectory()
+    {
+        Path = System.IO.Path.Combine(System.IO.Path.GetTempPath(), "covenant-authoring-tests-" + Guid.NewGuid().ToString("N"));
+        Directory.CreateDirectory(Path);
+    }
+
+    public string Path { get; }
+
+    public void Dispose()
+    {
+        try
+        {
+            Directory.Delete(Path, recursive: true);
+        }
+        catch
+        {
+        }
+    }
+}
diff --git a/authoring-ui.Tests/MainViewModelTests.cs b/authoring-ui.Tests/MainViewModelTests.cs
new file mode 100644
index 0000000..1354751
--- /dev/null
+++ b/authoring-ui.Tests/MainViewModelTests.cs
@@ -0,0 +1,74 @@
+using Covenant.Setup.Authoring;
+using Xunit;
+
+namespace Covenant.Setup.Authoring.Tests;
+
+public class MainViewModelTests
+{
+    [Fact]
+    public void Constructor_populates_default_manifest_entries()
+    {
+        var viewModel = new MainViewModel(() => null);
+
+        Assert.Equal("Covenant-Setup Sample App", viewModel.AppName);
+        Assert.Contains(viewModel.Directories, directory => directory.Path == @"{LocalAppData}\CovenantSetupSample");
+        Assert.Contains(viewModel.Files, file => file.Source == @"payload\sample_app.cmd");
+        Assert.Contains(viewModel.PurgePaths, path => path == @"{LocalAppData}\CovenantSetupSample");
+        Assert.Contains("app_name = \"Covenant-Setup Sample App\"", viewModel.TomlPreview);
+    }
+
+    [Fact]
+    public void Validate_rejects_unsupported_registry_roots()
+    {
+        var viewModel = new MainViewModel(() => null);
+        viewModel.Registry.Clear();
+        viewModel.PurgeRegistryBranches.Clear();
+        viewModel.AddRegistry(@"HKCR\Software\Bad", "Name", "Value");
+        viewModel.AddPurgeRegistryBranch(@"HKU\Software\Bad");
+
+        var validation = viewModel.Validate();
+
+        Assert.False(validation.IsValid);
+        Assert.Contains(validation.Errors, error => error.Contains(@"HKCR\Software\Bad", StringComparison.Ordinal));
+        Assert.Contains(validation.Errors, error => error.Contains(@"HKU\Software\Bad", StringComparison.Ordinal));
+    }
+
+    [Fact]
+    public void Validate_warns_when_manifest_requires_elevation()
+    {
+        var viewModel = new MainViewModel(() => null)
+        {
+            InstallRootToken = "{ProgramFilesX64}"
+        };
+        viewModel.ApplyDefaults(resetCollections: true);
+
+        var validation = viewModel.Validate();
+
+        Assert.True(validation.IsValid);
+        Assert.Contains(validation.Warnings, warning => warning.Contains("require elevation", StringComparison.OrdinalIgnoreCase));
+    }
+
+    [Fact]
+    public void Packaging_is_disabled_when_covenant_setup_is_missing()
+    {
+        var viewModel = new MainViewModel(() => null);
+
+        Assert.False(viewModel.HasCovenantSetupTool);
+        Assert.False(viewModel.CanPackage);
+        Assert.Contains("not found", viewModel.CovenantSetupStatus, StringComparison.OrdinalIgnoreCase);
+    }
+
+    [Fact]
+    public void Packaging_is_enabled_only_when_tool_and_valid_manifest_are_present()
+    {
+        var viewModel = new MainViewModel(() => new CovenantSetupTool(@"C:\tools\covenant-setup.exe"));
+
+        Assert.True(viewModel.HasCovenantSetupTool);
+        Assert.True(viewModel.CanPackage);
+
+        viewModel.AppName = string.Empty;
+
+        Assert.True(viewModel.HasValidationErrors);
+        Assert.False(viewModel.CanPackage);
+    }
+}
diff --git a/authoring-ui.Tests/ManifestTomlWriterTests.cs b/authoring-ui.Tests/ManifestTomlWriterTests.cs
new file mode 100644
index 0000000..b64493a
--- /dev/null
+++ b/authoring-ui.Tests/ManifestTomlWriterTests.cs
@@ -0,0 +1,108 @@
+using Covenant.Setup.Authoring;
+using Xunit;
+
+namespace Covenant.Setup.Authoring.Tests;
+
+public class ManifestTomlWriterTests
+{
+    [Fact]
+    public void Write_emits_current_manifest_schema()
+    {
+        var document = new ManifestDocument
+        {
+            AppName = "Sample App",
+            Directories =
+            [
+                new DirectorySpec(@"{LocalAppData}\Sample")
+            ],
+            Files =
+            [
+                new FileSpec(@"payload\app.exe", @"{LocalAppData}\Sample\bin\app.exe")
+            ],
+            Registry =
+            [
+                new RegistrySpec(@"HKCU\Software\Sample", "InstallRoot", @"{LocalAppData}\Sample")
+            ],
+            Shortcuts =
+            [
+                new ShortcutSpec(
+                    @"{Desktop}\Sample App.lnk",
+                    @"{LocalAppData}\Sample\bin\app.exe",
+                    "--profile default",
+                    @"{LocalAppData}\Sample",
+                    "Launch Sample App")
+            ],
+            Scripts =
+            [
+                new ScriptSpec(
+                    "powershell",
+                    ["-ExecutionPolicy", "Bypass", "-File", @"payload\post_install.ps1"],
+                    @"{LocalAppData}\Sample")
+            ],
+            Purge = new PurgeSpec
+            {
+                RegistryBranches = [@"HKCU\Software\Sample"],
+                Paths = [@"{LocalAppData}\Sample"]
+            }
+        };
+
+        var toml = Normalize(ManifestTomlWriter.Write(document));
+
+        const string expected = """
+app_name = "Sample App"
+
+[[directories]]
+path = "{LocalAppData}\\Sample"
+
+[[files]]
+source = "payload\\app.exe"
+destination = "{LocalAppData}\\Sample\\bin\\app.exe"
+
+[[registry]]
+key = "HKCU\\Software\\Sample"
+name = "InstallRoot"
+value = "{LocalAppData}\\Sample"
+
+[[shortcuts]]
+path = "{Desktop}\\Sample App.lnk"
+target = "{LocalAppData}\\Sample\\bin\\app.exe"
+arguments = "--profile default"
+working_directory = "{LocalAppData}\\Sample"
+description = "Launch Sample App"
+
+[[scripts]]
+command = "powershell"
+args = [
+  "-ExecutionPolicy",
+  "Bypass",
+  "-File",
+  "payload\\post_install.ps1"
+]
+working_directory = "{LocalAppData}\\Sample"
+
+[purge]
+registry_branches = ["HKCU\\Software\\Sample"]
+paths = ["{LocalAppData}\\Sample"]
+
+""";
+        Assert.Equal(Normalize(expected), toml);
+    }
+
+    [Fact]
+    public void Write_escapes_toml_strings()
+    {
+        var document = new ManifestDocument
+        {
+            AppName = "Quoted \"App\"\nTabbed\tPath",
+            Directories = [new DirectorySpec(@"C:\Apps\Sample")],
+            Purge = new PurgeSpec()
+        };
+
+        var toml = Normalize(ManifestTomlWriter.Write(document));
+
+        Assert.Contains("app_name = \"Quoted \\\"App\\\"\\nTabbed\\tPath\"", toml);
+        Assert.Contains("path = \"C:\\\\Apps\\\\Sample\"", toml);
+    }
+
+    private static string Normalize(string value) => value.Replace("\r\n", "\n");
+}
diff --git a/authoring-ui/Covenant.Setup.Authoring.csproj b/authoring-ui/Covenant.Setup.Authoring.csproj
index 8edd04a..71d81cb 100644
--- a/authoring-ui/Covenant.Setup.Authoring.csproj
+++ b/authoring-ui/Covenant.Setup.Authoring.csproj
@@ -18,4 +18,7 @@
   <ItemGroup>
     <PackageReference Include="Microsoft.WindowsAppSDK" Version="2.0.1" />
   </ItemGroup>
+  <ItemGroup>
+    <InternalsVisibleTo Include="Covenant.Setup.Authoring.Tests" />
+  </ItemGroup>
 </Project>
diff --git a/authoring-ui/CovenantSetupTool.cs b/authoring-ui/CovenantSetupTool.cs
index cdbd7f9..27cd4ca 100644
--- a/authoring-ui/CovenantSetupTool.cs
+++ b/authoring-ui/CovenantSetupTool.cs
@@ -15,7 +15,12 @@ internal static class CovenantSetupToolLocator
 {
     public static CovenantSetupTool? Find()
     {
-        foreach (var candidate in CandidatePaths())
+        return Find(CandidateDirectories());
+    }
+
+    internal static CovenantSetupTool? Find(IEnumerable<string> candidateDirectories)
+    {
+        foreach (var candidate in CandidatePaths(candidateDirectories))
         {
             if (File.Exists(candidate))
             {
@@ -26,10 +31,10 @@ internal static class CovenantSetupToolLocator
         return null;
     }
 
-    private static IEnumerable<string> CandidatePaths()
+    private static IEnumerable<string> CandidatePaths(IEnumerable<string> candidateDirectories)
     {
         var seen = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
-        foreach (var directory in CandidateDirectories())
+        foreach (var directory in candidateDirectories)
         {
             var candidate = System.IO.Path.Combine(directory, "covenant-setup.exe");
             if (seen.Add(candidate))
@@ -91,22 +96,9 @@ internal static class CovenantSetupPackager
         var error = new StringBuilder();
         using var process = new Process
         {
-            StartInfo = new ProcessStartInfo
-            {
-                FileName = tool.Path,
-                WorkingDirectory = System.IO.Path.GetDirectoryName(manifestPath) ?? Environment.CurrentDirectory,
-                UseShellExecute = false,
-                CreateNoWindow = true,
-                RedirectStandardOutput = true,
-                RedirectStandardError = true
-            },
+            StartInfo = CreateStartInfo(tool, manifestPath, outputDirectory),
             EnableRaisingEvents = true
         };
-        process.StartInfo.ArgumentList.Add("--json");
-        process.StartInfo.ArgumentList.Add("package");
-        process.StartInfo.ArgumentList.Add(manifestPath);
-        process.StartInfo.ArgumentList.Add("--output");
-        process.StartInfo.ArgumentList.Add(outputDirectory);
 
         process.OutputDataReceived += (_, args) =>
         {
@@ -133,4 +125,29 @@ internal static class CovenantSetupPackager
             output.ToString().Trim(),
             error.ToString().Trim());
     }
+
+    internal static ProcessStartInfo CreateStartInfo(
+        CovenantSetupTool tool,
+        string manifestPath,
+        string outputDirectory)
+    {
+        var manifestDirectory = System.IO.Path.GetDirectoryName(manifestPath);
+        var startInfo = new ProcessStartInfo
+        {
+            FileName = tool.Path,
+            WorkingDirectory = string.IsNullOrWhiteSpace(manifestDirectory)
+                ? Environment.CurrentDirectory
+                : manifestDirectory,
+            UseShellExecute = false,
+            CreateNoWindow = true,
+            RedirectStandardOutput = true,
+            RedirectStandardError = true
+        };
+        startInfo.ArgumentList.Add("--json");
+        startInfo.ArgumentList.Add("package");
+        startInfo.ArgumentList.Add(manifestPath);
+        startInfo.ArgumentList.Add("--output");
+        startInfo.ArgumentList.Add(outputDirectory);
+        return startInfo;
+    }
 }
diff --git a/authoring-ui/MainViewModel.cs b/authoring-ui/MainViewModel.cs
index b6b2bb0..29d6736 100644
--- a/authoring-ui/MainViewModel.cs
+++ b/authoring-ui/MainViewModel.cs
@@ -18,9 +18,16 @@ internal sealed partial class MainViewModel : INotifyPropertyChanged
     private string _tomlPreview = string.Empty;
     private string _validationSummary = string.Empty;
     private bool _hasValidationErrors;
+    private readonly Func<CovenantSetupTool?> _locateCovenantSetupTool;
 
     public MainViewModel()
+        : this(CovenantSetupToolLocator.Find)
     {
+    }
+
+    internal MainViewModel(Func<CovenantSetupTool?> locateCovenantSetupTool)
+    {
+        _locateCovenantSetupTool = locateCovenantSetupTool;
         Directories.CollectionChanged += CollectionChanged;
         Files.CollectionChanged += CollectionChanged;
         Registry.CollectionChanged += CollectionChanged;
@@ -170,7 +177,7 @@ internal sealed partial class MainViewModel : INotifyPropertyChanged
 
     public void RefreshCovenantSetupTool()
     {
-        CovenantSetupTool = CovenantSetupToolLocator.Find();
+        CovenantSetupTool = _locateCovenantSetupTool();
         CovenantSetupStatus = CovenantSetupTool is null
             ? "covenant-setup.exe was not found. Packaging is disabled."
             : "Packaging enabled: " + CovenantSetupTool.Path;
diff --git a/authoring-ui/README.md b/authoring-ui/README.md
index d6b55bb..8da2157 100644
--- a/authoring-ui/README.md
+++ b/authoring-ui/README.md
@@ -8,6 +8,12 @@ Run from the repository root:
 dotnet run --project .\authoring-ui\Covenant.Setup.Authoring.csproj
 ```
 
+Run unit tests from the repository root:
+
+```powershell
+dotnet test .\authoring-ui.Tests\Covenant.Setup.Authoring.Tests.csproj
+```
+
 The app edits the current manifest schema:
 
 - `app_name`