Add tests for RazorCompile target

This target should be callable on its own without using Build so it
deserves a few tests.

test/Microsoft.AspNetCore.Razor.Design.Test/IntegrationTests/RazorCompileIntegrationTest.cs

@@ -0,0 +1,44 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.IO;
+using System.Threading.Tasks;
+using Xunit;
+
+namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
+{
+    public class RazorCompileIntegrationTest : MSBuildIntegrationTestBase
+    {
+        [Fact]
+        [InitializeTestProject("SimpleMvc")]
+        public async Task RazorCompile_Success_CompilesAssembly()
+        {
+            var result = await DotnetMSBuild("RazorCompile");
+
+            Assert.BuildPassed(result);
+
+            // RazorGenerate should compile the assembly and pdb.
+            Assert.FileExists(result, IntermediateOutputPath, "SimpleMvc.dll");
+            Assert.FileExists(result, IntermediateOutputPath, "SimpleMvc.pdb");
+            Assert.FileExists(result, IntermediateOutputPath, "SimpleMvc.PrecompiledViews.dll");
+            Assert.FileExists(result, IntermediateOutputPath, "SimpleMvc.PrecompiledViews.pdb");
+        }
+
+        [Fact]
+        [InitializeTestProject("SimpleMvc")]
+        public async Task RazorCompile_NoopsWithNoFiles()
+        {
+            Directory.Delete(Path.Combine(Project.DirectoryPath, "Views"), recursive: true);
+
+            var result = await DotnetMSBuild("RazorCompile");
+
+            Assert.BuildPassed(result);
+
+            // Everything we do should noop - including building the app. 
+            Assert.FileDoesNotExist(result, IntermediateOutputPath, "SimpleMvc.dll");
+            Assert.FileDoesNotExist(result, IntermediateOutputPath, "SimpleMvc.pdb");
+            Assert.FileDoesNotExist(result, IntermediateOutputPath, "SimpleMvc.PrecompiledViews.dll");
+            Assert.FileDoesNotExist(result, IntermediateOutputPath, "SimpleMvc.PrecompiledViews.pdb");
+        }
+    }
+}