Install latest build of templates before running tests

test/Helpers/TemplatePackageInstaller.cs

@@ -0,0 +1,86 @@
+using System;
+using System.IO;
+using System.Linq;
+
+namespace Templates.Test.Helpers
+{
+    internal static class TemplatePackageInstaller
+    {
+        private static readonly string[] _templatePackages = new[]
+        {
+            "Microsoft.DotNet.Web.ItemTemplates",
+            "Microsoft.DotNet.Web.ProjectTemplates.2.0",
+        };
+
+        public static void ReinstallTemplatePackages()
+        {
+            // Remove any previous or prebundled version of the template packages
+            foreach (var packageName in _templatePackages)
+            {
+                var proc = ProcessEx.Run(
+                    Directory.GetCurrentDirectory(),
+                    "dotnet",
+                    $"new --uninstall {packageName}");
+                proc.WaitForExit(assertSuccess: true);
+            }
+
+            VerifyCannotFindTemplate("ASP.NET Core Empty");
+
+            // Locate the artifacts directory containing the built template packages
+            var solutionDir = FindAncestorDirectoryContaining("Templating.sln");
+            var artifactsDir = Path.Combine(solutionDir, "artifacts");
+            var builtPackages = Directory.GetFiles(artifactsDir, "*.nupkg");
+            foreach (var packagePath in builtPackages)
+            {
+                if (_templatePackages.Any(name => Path.GetFileName(packagePath).StartsWith(name, StringComparison.OrdinalIgnoreCase)))
+                {
+                    Console.WriteLine($"Installing templates package {packagePath}...");
+                    var proc = ProcessEx.Run(
+                        Directory.GetCurrentDirectory(),
+                        "dotnet",
+                        $"new --install \"{packagePath}\"");
+                    proc.WaitForExit(assertSuccess: true);
+                }
+            }
+        }
+
+        private static void VerifyCannotFindTemplate(string templateName)
+        {
+            // Verify we really did remove the previous templates
+            var tempDir = Path.Combine(Path.GetTempPath(), Guid.NewGuid().ToString("D"));
+            Directory.CreateDirectory(tempDir);
+            try
+            {
+                var proc = ProcessEx.Run(
+                    tempDir,
+                    "dotnet",
+                    $"new \"{templateName}\"");
+                proc.WaitForExit(assertSuccess: false);
+                if (!proc.Error.Contains($"No templates matched the input template name: {templateName}."))
+                {
+                    throw new InvalidOperationException($"Failed to uninstall previous templates. The template '{templateName}' could still be found.");
+                }
+            }
+            finally
+            {
+                Directory.Delete(tempDir);
+            }
+        }
+
+        private static string FindAncestorDirectoryContaining(string filename)
+        {
+            var dir = Directory.GetCurrentDirectory();
+            while (dir != null)
+            {
+                if (File.Exists(Path.Combine(dir, filename)))
+                {
+                    return dir;
+                }
+
+                dir = Directory.GetParent(dir)?.FullName;
+            }
+
+            throw new InvalidOperationException($"Could not find any ancestor directory containing {filename} at or above {Directory.GetCurrentDirectory()}");
+        }
+    }
+}

test/Helpers/TemplateTestBase.cs

@@ -12,6 +12,11 @@ namespace Templates.Test
         protected string ProjectName { get; set; }
         protected string TemplateOutputDir { get; private set; }
 
+        static TemplateTestBase()
+        {
+            TemplatePackageInstaller.ReinstallTemplatePackages();
+        }
+
         public TemplateTestBase()
         {
             ProjectName = Guid.NewGuid().ToString().Replace("-", "");