Add Tests for incrementality

Microsoft.DotNet.Cli.sln

@@ -87,6 +87,10 @@ Project("{8BB2217D-0F2D-49D1-97BC-3654ED321F3B}") = "Microsoft.DotNet.Tools.Publ
 EndProject
 Project("{8BB2217D-0F2D-49D1-97BC-3654ED321F3B}") = "TestLibrary", "test\TestProjects\TestLibrary\TestLibrary.xproj", "{947DD232-8D9B-4B78-9C6A-94F807D2DD58}"
 EndProject
+Project("{8BB2217D-0F2D-49D1-97BC-3654ED321F3B}") = "Microsoft.DotNet.Tools.Builder.Tests", "test\Microsoft.DotNet.Tools.Builder.Tests\Microsoft.DotNet.Tools.Builder.Tests.xproj", "{833FFEE1-7EED-4F51-8DFD-946D48833333}"
+EndProject
+Project("{8BB2217D-0F2D-49D1-97BC-3654ED321F3B}") = "TestProjectToProjectDependencies", "test\TestProjects\TestProjectToProjectDependencies\TestProjectToProjectDependencies.xproj", "{947DD232-8D9B-4B78-9C6A-94F807D22222}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -659,6 +663,38 @@ Global
 		{947DD232-8D9B-4B78-9C6A-94F807D2DD58}.RelWithDebInfo|Any CPU.Build.0 = Release|Any CPU
 		{947DD232-8D9B-4B78-9C6A-94F807D2DD58}.RelWithDebInfo|x64.ActiveCfg = Release|Any CPU
 		{947DD232-8D9B-4B78-9C6A-94F807D2DD58}.RelWithDebInfo|x64.Build.0 = Release|Any CPU
+		{833FFEE1-7EED-4F51-8DFD-946D48833333}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{833FFEE1-7EED-4F51-8DFD-946D48833333}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{833FFEE1-7EED-4F51-8DFD-946D48833333}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{833FFEE1-7EED-4F51-8DFD-946D48833333}.Debug|x64.Build.0 = Debug|Any CPU
+		{833FFEE1-7EED-4F51-8DFD-946D48833333}.MinSizeRel|Any CPU.ActiveCfg = Debug|Any CPU
+		{833FFEE1-7EED-4F51-8DFD-946D48833333}.MinSizeRel|Any CPU.Build.0 = Debug|Any CPU
+		{833FFEE1-7EED-4F51-8DFD-946D48833333}.MinSizeRel|x64.ActiveCfg = Debug|Any CPU
+		{833FFEE1-7EED-4F51-8DFD-946D48833333}.MinSizeRel|x64.Build.0 = Debug|Any CPU
+		{833FFEE1-7EED-4F51-8DFD-946D48833333}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{833FFEE1-7EED-4F51-8DFD-946D48833333}.Release|Any CPU.Build.0 = Release|Any CPU
+		{833FFEE1-7EED-4F51-8DFD-946D48833333}.Release|x64.ActiveCfg = Release|Any CPU
+		{833FFEE1-7EED-4F51-8DFD-946D48833333}.Release|x64.Build.0 = Release|Any CPU
+		{833FFEE1-7EED-4F51-8DFD-946D48833333}.RelWithDebInfo|Any CPU.ActiveCfg = Release|Any CPU
+		{833FFEE1-7EED-4F51-8DFD-946D48833333}.RelWithDebInfo|Any CPU.Build.0 = Release|Any CPU
+		{833FFEE1-7EED-4F51-8DFD-946D48833333}.RelWithDebInfo|x64.ActiveCfg = Release|Any CPU
+		{833FFEE1-7EED-4F51-8DFD-946D48833333}.RelWithDebInfo|x64.Build.0 = Release|Any CPU
+		{947DD232-8D9B-4B78-9C6A-94F807D22222}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{947DD232-8D9B-4B78-9C6A-94F807D22222}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{947DD232-8D9B-4B78-9C6A-94F807D22222}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{947DD232-8D9B-4B78-9C6A-94F807D22222}.Debug|x64.Build.0 = Debug|Any CPU
+		{947DD232-8D9B-4B78-9C6A-94F807D22222}.MinSizeRel|Any CPU.ActiveCfg = Debug|Any CPU
+		{947DD232-8D9B-4B78-9C6A-94F807D22222}.MinSizeRel|Any CPU.Build.0 = Debug|Any CPU
+		{947DD232-8D9B-4B78-9C6A-94F807D22222}.MinSizeRel|x64.ActiveCfg = Debug|Any CPU
+		{947DD232-8D9B-4B78-9C6A-94F807D22222}.MinSizeRel|x64.Build.0 = Debug|Any CPU
+		{947DD232-8D9B-4B78-9C6A-94F807D22222}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{947DD232-8D9B-4B78-9C6A-94F807D22222}.Release|Any CPU.Build.0 = Release|Any CPU
+		{947DD232-8D9B-4B78-9C6A-94F807D22222}.Release|x64.ActiveCfg = Release|Any CPU
+		{947DD232-8D9B-4B78-9C6A-94F807D22222}.Release|x64.Build.0 = Release|Any CPU
+		{947DD232-8D9B-4B78-9C6A-94F807D22222}.RelWithDebInfo|Any CPU.ActiveCfg = Release|Any CPU
+		{947DD232-8D9B-4B78-9C6A-94F807D22222}.RelWithDebInfo|Any CPU.Build.0 = Release|Any CPU
+		{947DD232-8D9B-4B78-9C6A-94F807D22222}.RelWithDebInfo|x64.ActiveCfg = Release|Any CPU
+		{947DD232-8D9B-4B78-9C6A-94F807D22222}.RelWithDebInfo|x64.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -700,5 +736,7 @@ Global
 		{833FFEE1-7EED-4F51-8DFD-946D48893D6E} = {17735A9D-BFD9-4585-A7CB-3208CA6EA8A7}
 		{386D412C-003C-47B1-8258-0E35865CB7C4} = {17735A9D-BFD9-4585-A7CB-3208CA6EA8A7}
 		{947DD232-8D9B-4B78-9C6A-94F807D2DD58} = {713CBFBB-5392-438D-B766-A9A585EF1BB8}
+		{833FFEE1-7EED-4F51-8DFD-946D48833333} = {17735A9D-BFD9-4585-A7CB-3208CA6EA8A7}
+		{947DD232-8D9B-4B78-9C6A-94F807D22222} = {713CBFBB-5392-438D-B766-A9A585EF1BB8}
 	EndGlobalSection
 EndGlobal

scripts/test/runtests.ps1

@@ -11,9 +11,10 @@ $TestBinRoot = "$RepoRoot\artifacts\tests"
 
 $TestProjects = @(
     "E2E",
-    "StreamForwarderTests"
+    "StreamForwarderTests",
-    "Microsoft.DotNet.Tools.Publish.Tests"
+    "Microsoft.DotNet.Tools.Publish.Tests",
-    "Microsoft.DotNet.Tools.Compiler.Tests"
+    "Microsoft.DotNet.Tools.Compiler.Tests",
+    "Microsoft.DotNet.Tools.Builder.Tests"
 )
 
 # Publish each test project

scripts/test/runtests.sh

@@ -24,6 +24,7 @@ TestProjects=( \
     StreamForwarderTests \
     Microsoft.DotNet.Tools.Publish.Tests \
     Microsoft.DotNet.Tools.Compiler.Tests \
+    Microsoft.DotNet.Tools.Builder.Tests \
 )
 
 for project in ${TestProjects[@]}

test/E2E/EndToEndTest.cs

@@ -45,7 +45,7 @@ namespace Microsoft.DotNet.Tests.EndToEnd
 
             buildCommand.Execute().Should().Pass();
 
-            TestOutputExecutable(OutputDirectory, buildCommand.GetOutputExecutableName());
+            TestOutputExecutable(OutputDirectory, buildCommand.GetOutputExecutableName(), s_expectedOutput);
         }
 
         [Fact]
@@ -56,13 +56,13 @@ namespace Microsoft.DotNet.Tests.EndToEnd
             // first build
             var buildCommand = new BuildCommand(TestProject, output: OutputDirectory);
             buildCommand.Execute().Should().Pass();
-            TestOutputExecutable(OutputDirectory, buildCommand.GetOutputExecutableName());
+            TestOutputExecutable(OutputDirectory, buildCommand.GetOutputExecutableName(), s_expectedOutput);
 
             var latestWriteTimeFirstBuild = GetLastWriteTimeOfDirectoryFiles(OutputDirectory);
 
             // second build; should get skipped (incremental because no inputs changed)
             buildCommand.Execute().Should().Pass();
-            TestOutputExecutable(OutputDirectory, buildCommand.GetOutputExecutableName());
+            TestOutputExecutable(OutputDirectory, buildCommand.GetOutputExecutableName(), s_expectedOutput);
 
             var latestWriteTimeSecondBuild = GetLastWriteTimeOfDirectoryFiles(OutputDirectory);
             Assert.Equal(latestWriteTimeFirstBuild, latestWriteTimeSecondBuild);
@@ -71,68 +71,12 @@ namespace Microsoft.DotNet.Tests.EndToEnd
 
             // third build; should get compiled because the source file got touched
             buildCommand.Execute().Should().Pass();
-            TestOutputExecutable(OutputDirectory, buildCommand.GetOutputExecutableName());
+            TestOutputExecutable(OutputDirectory, buildCommand.GetOutputExecutableName(), s_expectedOutput);
 
             var latestWriteTimeThirdBuild = GetLastWriteTimeOfDirectoryFiles(OutputDirectory);
             Assert.NotEqual(latestWriteTimeSecondBuild, latestWriteTimeThirdBuild);
         }
 
-        [Fact]
-        public void TestDotnetForceIncrementalUnsafe()
-        {
-            TestSetup();
-
-            // first build
-            var buildCommand = new BuildCommand(TestProject, output: OutputDirectory);
-            buildCommand.Execute().Should().Pass();
-            TestOutputExecutable(OutputDirectory, buildCommand.GetOutputExecutableName());
-
-            var latestWriteTimeFirstBuild = GetLastWriteTimeOfDirectoryFiles(OutputDirectory);
-
-            // second build; will get recompiled due to force unsafe flag
-            buildCommand = new BuildCommand(TestProject, output: OutputDirectory, forceIncrementalUnsafe:true);
-            buildCommand.Execute().Should().Pass();
-            TestOutputExecutable(OutputDirectory, buildCommand.GetOutputExecutableName());
-
-            var latestWriteTimeSecondBuild = GetLastWriteTimeOfDirectoryFiles(OutputDirectory);
-            Assert.NotEqual(latestWriteTimeFirstBuild, latestWriteTimeSecondBuild);
-        }
-
-        [Fact]
-        public void TestDotnetIncrementalBuildDeleteOutputFile()
-        {
-            TestSetup();
-
-            // first build
-            var buildCommand = new BuildCommand(TestProject, output: OutputDirectory);
-            buildCommand.Execute().Should().Pass();
-            TestOutputExecutable(OutputDirectory, buildCommand.GetOutputExecutableName());
-
-            var latestWriteTimeFirstBuild = GetLastWriteTimeOfDirectoryFiles(OutputDirectory);
-
-            Reporter.Verbose.WriteLine($"Files in {OutputDirectory}");
-            foreach (var file in Directory.EnumerateFiles(OutputDirectory))
-            {
-                Reporter.Verbose.Write($"\t {file}");
-            }
-
-            // delete output files
-            foreach (var outputFile in Directory.EnumerateFiles(OutputDirectory).Where(f => Path.GetFileName(f).StartsWith(s_testdirName, StringComparison.OrdinalIgnoreCase)))
-            {
-                Reporter.Verbose.WriteLine($"Delete {outputFile}");
-
-                File.Delete(outputFile);
-                Assert.False(File.Exists(outputFile));
-            }
-
-            // second build; should get rebuilt since we deleted output items
-            buildCommand.Execute().Should().Pass();
-            TestOutputExecutable(OutputDirectory, buildCommand.GetOutputExecutableName());
-
-            var latestWriteTimeSecondBuild = GetLastWriteTimeOfDirectoryFiles(OutputDirectory);
-            Assert.NotEqual(latestWriteTimeFirstBuild, latestWriteTimeSecondBuild);
-        }
-
         [Fact]
         [ActiveIssue(712, PlatformID.Windows | PlatformID.OSX | PlatformID.Linux)]
         public void TestDotnetBuildNativeRyuJit()
@@ -148,7 +92,7 @@ namespace Microsoft.DotNet.Tests.EndToEnd
             buildCommand.Execute().Should().Pass();
 
             var nativeOut = Path.Combine(OutputDirectory, "native");
-            TestOutputExecutable(nativeOut, buildCommand.GetOutputExecutableName());
+            TestOutputExecutable(nativeOut, buildCommand.GetOutputExecutableName(), s_expectedOutput);
         }
 
         [Fact]
@@ -165,7 +109,7 @@ namespace Microsoft.DotNet.Tests.EndToEnd
             buildCommand.Execute().Should().Pass();
 
             var nativeOut = Path.Combine(OutputDirectory, "native");
-            TestOutputExecutable(nativeOut, buildCommand.GetOutputExecutableName());
+            TestOutputExecutable(nativeOut, buildCommand.GetOutputExecutableName(), s_expectedOutput);
         }
 
         [Fact]
@@ -182,13 +126,13 @@ namespace Microsoft.DotNet.Tests.EndToEnd
             // first build
             var buildCommand = new BuildCommand(TestProject, output: OutputDirectory, native: true, nativeCppMode: true);
             buildCommand.Execute().Should().Pass();
-            TestOutputExecutable(nativeOut, buildCommand.GetOutputExecutableName());
+            TestOutputExecutable(nativeOut, buildCommand.GetOutputExecutableName(), s_expectedOutput);
 
             var latestWriteTimeFirstBuild = GetLastWriteTimeOfDirectoryFiles(OutputDirectory);
 
             // second build; should be skipped because nothing changed
             buildCommand.Execute().Should().Pass();
-            TestOutputExecutable(nativeOut, buildCommand.GetOutputExecutableName());
+            TestOutputExecutable(nativeOut, buildCommand.GetOutputExecutableName(), s_expectedOutput);
 
             var latestWriteTimeSecondBuild = GetLastWriteTimeOfDirectoryFiles(OutputDirectory);
             Assert.Equal(latestWriteTimeFirstBuild, latestWriteTimeSecondBuild);
@@ -220,7 +164,7 @@ namespace Microsoft.DotNet.Tests.EndToEnd
             var publishCommand = new PublishCommand(TestProject, output: OutputDirectory);
             publishCommand.Execute().Should().Pass();
 
-            TestOutputExecutable(OutputDirectory, publishCommand.GetOutputExecutable());    
+            TestOutputExecutable(OutputDirectory, publishCommand.GetOutputExecutable(), s_expectedOutput);    
         }
 
         private void TestSetup()
@@ -245,19 +189,6 @@ namespace Microsoft.DotNet.Tests.EndToEnd
             Directory.SetCurrentDirectory(currentDirectory);
         }
 
-        private void TestOutputExecutable(string outputDir, string executableName)
-        {
-            var executablePath = Path.Combine(outputDir, executableName);
-
-            var executableCommand = new TestCommand(executablePath);
-
-            var result = executableCommand.ExecuteWithCapturedOutput("");
-
-            result.Should().HaveStdOut(s_expectedOutput);
-            result.Should().NotHaveStdErr();
-            result.Should().Pass();
-        }
-
         private bool IsCentOS()
         {
             if(RuntimeInformation.IsOSPlatform(OSPlatform.Linux))

test/Microsoft.DotNet.Tools.Builder.Tests/BuildProjectToProjectTests.cs

@@ -0,0 +1,81 @@
+// Copyright (c) .NET Foundation and contributors. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using Microsoft.DotNet.Cli.Utils;
+using Microsoft.DotNet.Tools.Test.Utilities;
+using Xunit;
+
+namespace Microsoft.DotNet.Tools.Builder.Tests
+{
+    public class ProjectToProjectDependenciesIncrementalTest : IncrementalTestBase
+    {
+        private string[] _projects = new[] { "L0", "L11", "L12", "L21", "L22" };
+
+        private string _testProjectsRoot = @"TestProjects";
+        private string _testProject = "TestProjectToProjectDependencies";
+        private TempDirectory tempProjectRoot;
+
+        public ProjectToProjectDependenciesIncrementalTest() : base(
+            Path.Combine("TestProjects", "TestProjectToProjectDependencies"),
+            "L0",
+            "L0 L11 L12 L22 L21 L12 L22 " + Environment.NewLine)
+        {
+        }
+
+        [Theory,
+        InlineData("L0", new[] { "L0" }),
+        InlineData("L11", new[] { "L0", "L11" }),
+        InlineData("L12", new[] { "L0", "L11", "L12" }),
+        InlineData("L22", new[] { "L0", "L11", "L12", "L22" }),
+        InlineData("L21", new[] { "L0", "L11", "L21" })
+        ]
+        public void TestIncrementalBuildOfDependencyGraph(string projectToTouch, string[] expectedRebuiltProjects)
+        {
+
+            // first clean build; all projects required compilation
+            var result1 = BuildProject();
+            AssertRebuilt(result1, _projects);
+
+            // second build; nothing changed; no project required compilation
+            var result2 = BuildProject();
+            AssertRebuilt(result2, Array.Empty<string>());
+
+            //modify the source code of a project
+            TouchSourcesOfProject(projectToTouch);
+
+            // third build; all projects on the paths from touched project to root project need to be rebuilt
+            var result3 = BuildProject();
+            AssertRebuilt(result3, expectedRebuiltProjects);
+        }
+
+        // compute A - B
+        private T[] SetDifference<T>(T[] A, T[] B)
+        {
+            var setA = new HashSet<T>(A);
+            setA.ExceptWith(B);
+            return setA.ToArray();
+        }
+
+        private void AssertRebuilt(CommandResult buildResult, string[] expectedRebuilt)
+        {
+            foreach (var rebuiltProject in expectedRebuilt)
+            {
+                AssertProjectCompiled(rebuiltProject, buildResult);
+            }
+
+            foreach (var skippedProject in SetDifference(_projects, expectedRebuilt))
+            {
+                AssertProjectSkipped(skippedProject, buildResult);
+            }
+        }
+
+        protected override string GetProjectDirectory(string projectName)
+        {
+            return Path.Combine(_tempProjectRoot.Path, "src", projectName);
+        }
+    }
+}

test/Microsoft.DotNet.Tools.Builder.Tests/IncrementalTestBase.cs

@@ -0,0 +1,117 @@
+// Copyright (c) .NET Foundation and contributors. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using Microsoft.DotNet.Cli.Utils;
+using Microsoft.DotNet.Tools.Test.Utilities;
+using Xunit;
+
+namespace Microsoft.DotNet.Tools.Builder.Tests
+{
+    public class IncrementalTestBase : TestBase
+    {
+        protected readonly TempDirectory _tempProjectRoot;
+
+        private readonly string _testProjectsRoot;
+        protected readonly string _mainProject;
+        protected readonly string _expectedOutput;
+
+        public IncrementalTestBase(string testProjectsRoot, string mainProject, string expectedOutput)
+        {
+            _testProjectsRoot = testProjectsRoot;
+            _mainProject = mainProject;
+            _expectedOutput = expectedOutput;
+
+            // create unique directories in the 'temp' folder
+            var root = Temp.CreateDirectory();
+
+            // recursively copy projects to the temp dir and restore them
+            _tempProjectRoot = root.CopyDirectory(testProjectsRoot);
+            RunRestore(_tempProjectRoot.Path);
+        }
+
+        protected void TouchSourcesOfProject()
+        {
+            TouchSourcesOfProject(_mainProject);
+        }
+
+        protected void TouchSourcesOfProject(string projectToTouch)
+        {
+            foreach (var sourceFile in GetSourceFilesForProject(projectToTouch))
+            {
+                TouchFile(sourceFile);
+            }
+        }
+
+        protected static void TouchFile(string file)
+        {
+            File.SetLastWriteTimeUtc(file, DateTime.UtcNow);
+        }
+
+        protected CommandResult BuildProject(bool forceIncrementalUnsafe = false, bool expectBuildFailure = false)
+        {
+            var outputDir = GetBinDirectory();
+            var mainProject = GetProjectFile(_mainProject);
+
+            var buildCommand = new BuildCommand(mainProject, output: outputDir, forceIncrementalUnsafe : forceIncrementalUnsafe);
+            var result = buildCommand.ExecuteWithCapturedOutput();
+
+            if (!expectBuildFailure)
+            {
+                result.Should().Pass();
+                TestOutputExecutable(outputDir, buildCommand.GetOutputExecutableName(), _expectedOutput);
+            }
+            else
+            {
+                result.Should().Fail();
+            }
+
+            return result;
+        }
+
+        protected static void AssertProjectSkipped(string skippedProject, CommandResult buildResult)
+        {
+            Assert.Contains($"Project {skippedProject} was previoulsy compiled. Skipping compilation.", buildResult.StdOut);
+        }
+
+        protected static void AssertProjectCompiled(string rebuiltProject, CommandResult buildResult)
+        {
+            Assert.Contains($"Project {rebuiltProject} will be compiled", buildResult.StdOut, StringComparison.OrdinalIgnoreCase);
+        }
+
+        protected string GetBinDirectory()
+        {
+            return Path.Combine(_tempProjectRoot.Path, "bin");
+        }
+
+        protected virtual string GetProjectDirectory(string projectName)
+        {
+            return Path.Combine(_tempProjectRoot.Path);
+        }
+
+        protected string GetProjectFile(string projectName)
+        {
+            return Path.Combine(GetProjectDirectory(projectName), "project.json");
+        }
+
+        private string GetOutputFileForProject(string projectName)
+        {
+            return Path.Combine(GetBinDirectory(), projectName + ".dll");
+        }
+
+        private IEnumerable<string> GetSourceFilesForProject(string projectName)
+        {
+            return Directory.EnumerateFiles(GetProjectDirectory(projectName)).
+                Where(f => f.EndsWith(".cs"));
+        }
+
+        private void RunRestore(string args)
+        {
+            var restoreCommand = new RestoreCommand();
+            restoreCommand.Execute($"--quiet {args}").Should().Pass();
+        }
+    }
+}

test/Microsoft.DotNet.Tools.Builder.Tests/IncrementalTests.cs

@@ -0,0 +1,130 @@
+// Copyright (c) .NET Foundation and contributors. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using Microsoft.DotNet.Cli.Utils;
+using Microsoft.DotNet.Tools.Test.Utilities;
+using Xunit;
+
+namespace Microsoft.DotNet.Tools.Builder.Tests
+{
+    public class IncrementalTests : IncrementalTestBase
+    {
+        private string _testProjectsRoot = @"TestProjects";
+        private string _testProject = "TestProjectToProjectDependencies";
+        private TempDirectory tempProjectRoot;
+
+        public IncrementalTests() : base(
+            Path.Combine("TestProjects", "TestSimpleIncrementalApp"),
+            "TestSimpleIncrementalApp",
+            "Hello World!" + Environment.NewLine)
+        {
+        }
+
+        [Fact]
+        public void TestForceIncrementalUnsafe()
+        {
+            var buildResult = BuildProject();
+            AssertProjectCompiled(_mainProject, buildResult);
+
+            buildResult = BuildProject(forceIncrementalUnsafe: true);
+            Assert.Contains("[Forced Unsafe]", buildResult.StdOut);
+        }
+
+        [Fact]
+        public void TestRebuildMissingPdb()
+        {
+            TestDeleteOutputWithExtension("pdb");
+        }
+
+        [Fact]
+        public void TestRebuildMissingDll()
+        {
+            TestDeleteOutputWithExtension("dll");
+        }
+
+        [Fact]
+        public void TestRebuildMissingXml()
+        {
+            TestDeleteOutputWithExtension("xml");
+        }
+
+        [Fact]
+        public void TestNoLockFile()
+        {
+
+            var buildResult = BuildProject();
+            AssertProjectCompiled(_mainProject, buildResult);
+
+            var lockFile = Path.Combine(_tempProjectRoot.Path, "project.lock.json");
+            Assert.True(File.Exists(lockFile));
+
+            File.Delete(lockFile);
+            Assert.False(File.Exists(lockFile));
+
+            buildResult = BuildProject(expectBuildFailure : true);
+            Assert.Contains("does not have a lock file", buildResult.StdErr);
+        }
+
+        [Fact]
+        public void TestRebuildChangedLockFile()
+        {
+
+            var buildResult = BuildProject();
+            AssertProjectCompiled(_mainProject, buildResult);
+
+            var lockFile = Path.Combine(_tempProjectRoot.Path, "project.lock.json");
+            TouchFile(lockFile);
+
+            buildResult = BuildProject();
+            AssertProjectCompiled(_mainProject, buildResult);
+        }
+
+        [Fact]
+        public void TestRebuildChangedProjectFile()
+        {
+
+            var buildResult = BuildProject();
+            AssertProjectCompiled(_mainProject, buildResult);
+
+            TouchFile(GetProjectFile(_mainProject));
+
+            buildResult = BuildProject();
+            AssertProjectCompiled(_mainProject, buildResult);
+        }
+
+        private void TestDeleteOutputWithExtension(string extension)
+        {
+
+            var buildResult = BuildProject();
+            AssertProjectCompiled(_mainProject, buildResult);
+
+            Reporter.Verbose.WriteLine($"Files in {GetBinDirectory()}");
+            foreach (var file in Directory.EnumerateFiles(GetBinDirectory()))
+            {
+                Reporter.Verbose.Write($"\t {file}");
+            }
+
+            // delete output files with extensions
+            foreach (var outputFile in Directory.EnumerateFiles(GetBinDirectory()).Where(f =>
+            {
+                var fileName = Path.GetFileName(f);
+                return fileName.StartsWith(_mainProject, StringComparison.OrdinalIgnoreCase) &&
+                       fileName.EndsWith(extension, StringComparison.OrdinalIgnoreCase);
+            }))
+            {
+                Reporter.Output.WriteLine($"Deleted {outputFile}");
+
+                File.Delete(outputFile);
+                Assert.False(File.Exists(outputFile));
+            }
+
+            // second build; should get rebuilt since we deleted an output item
+            buildResult = BuildProject();
+            AssertProjectCompiled(_mainProject, buildResult);
+        }
+    }
+}

test/Microsoft.DotNet.Tools.Builder.Tests/Microsoft.DotNet.Tools.Builder.Tests.xproj

@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="14.0.23107" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup>
+    <VisualStudioVersion Condition="'$(VisualStudioVersion)' == ''">14.0.23107</VisualStudioVersion>
+    <VSToolsPath Condition="'$(VSToolsPath)' == ''">$(MSBuildExtensionsPath32)\Microsoft\VisualStudio\v$(VisualStudioVersion)</VSToolsPath>
+  </PropertyGroup>
+  <Import Project="$(VSToolsPath)\DNX\Microsoft.DNX.Props" Condition="'$(VSToolsPath)' != ''" />
+  <PropertyGroup Label="Globals">
+    <ProjectGuid>833ffee1-7eed-4f51-8dfd-946d48833333</ProjectGuid>
+    <RootNamespace>Microsoft.DotNet.Tools.Builder.Tests</RootNamespace>
+    <BaseIntermediateOutputPath Condition="'$(BaseIntermediateOutputPath)'=='' ">..\..\artifacts\obj\$(MSBuildProjectName)</BaseIntermediateOutputPath>
+    <OutputPath Condition="'$(OutputPath)'=='' ">..\..\artifacts\bin\$(MSBuildProjectName)\</OutputPath>
+  </PropertyGroup>
+
+  <PropertyGroup>
+    <SchemaVersion>2.0</SchemaVersion>
+  </PropertyGroup>
+  <Import Project="$(VSToolsPath)\DNX\Microsoft.DNX.targets" Condition="'$(VSToolsPath)' != ''" />
+</Project>

test/Microsoft.DotNet.Tools.Builder.Tests/project.json

@@ -0,0 +1,23 @@
+{
+  "version": "1.0.0-*",  
+  
+  "dependencies": {
+    "NETStandard.Library": "1.0.0-rc2-23704",
+    "Microsoft.NETCore.TestHost" : "1.0.0-*",
+
+    "xunit": "2.1.0",
+    "xunit.console.netcore": "1.0.2-prerelease-00101",
+    "xunit.netcore.extensions": "1.0.0-prerelease-*",
+    "xunit.runner.utility": "2.1.0",
+
+    "Microsoft.DotNet.Tools.Tests.Utilities": { "target": "project" },
+    "Microsoft.DotNet.Cli.Utils": {
+        "target": "project",
+        "type": "build"
+    }
+  },
+
+    "frameworks": {
+        "dnxcore50": { }
+    }
+}

test/Microsoft.DotNet.Tools.Tests.Utilities/Commands/BuildCommand.cs

@@ -201,7 +201,7 @@ namespace Microsoft.DotNet.Tools.Test.Utilities
 
         public override CommandResult ExecuteWithCapturedOutput(string args = "")
         {
-            args = $"build {BuildArgs()} {args}";
+            args = $"--verbose build {BuildArgs()} {args}";
             return base.ExecuteWithCapturedOutput(args);
         }
 

test/Microsoft.DotNet.Tools.Tests.Utilities/TempFileSystem/TempDirectory.cs

@@ -70,6 +70,31 @@ namespace Microsoft.DotNet.Tools.Test.Utilities
             return _root.AddFile(new DisposableFile(filePath));
         }
 
+        /// <summary>
+        /// Recursively copy the provided directory into this TempDirectory.
+        /// Does not handle links.
+        /// </summary>
+        /// <param name="sourceDirectory"></param>
+        /// <returns></returns>
+        public TempDirectory CopyDirectory(string sourceDirectory)
+        {
+            Debug.Assert(Directory.Exists(sourceDirectory));
+             
+            var tempCopy = CreateDirectory(new DirectoryInfo(sourceDirectory).Name);
+
+            foreach(var file in Directory.EnumerateFiles(sourceDirectory))
+            {
+                tempCopy.CopyFile(file);
+            }
+
+            foreach(var directory in Directory.EnumerateDirectories(sourceDirectory))
+            {
+                tempCopy.CopyDirectory(directory);
+            }
+
+            return tempCopy;
+        }
+ 
         /// <summary>
         /// Creates a subdirectory in this directory.
         /// </summary>

test/Microsoft.DotNet.Tools.Tests.Utilities/TestBase.cs

@@ -3,8 +3,10 @@
 
 using System;
 using System.Collections.Generic;
+using System.IO;
 using System.Linq;
 using System.Threading.Tasks;
+using Microsoft.DotNet.Cli.Utils;
 
 namespace Microsoft.DotNet.Tools.Test.Utilities
 {
@@ -55,5 +57,18 @@ namespace Microsoft.DotNet.Tools.Test.Utilities
                 string.Equals("1", val, StringComparison.OrdinalIgnoreCase) ||
                 string.Equals("on", val, StringComparison.OrdinalIgnoreCase));
         }
+
+        protected void TestOutputExecutable(string outputDir, string executableName, string expectedOutput)
+        {
+            var executablePath = Path.Combine(outputDir, executableName);
+
+            var executableCommand = new TestCommand(executablePath);
+
+            var result = executableCommand.ExecuteWithCapturedOutput("");
+
+            result.Should().HaveStdOut(expectedOutput);
+            result.Should().NotHaveStdErr();
+            result.Should().Pass();
+        }
     }
 }

test/TestProjects/TestProjectToProjectDependencies/TestProjectToProjectDependencies.xproj

@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="14.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup>
+    <VisualStudioVersion Condition="'$(VisualStudioVersion)' == ''">14.0</VisualStudioVersion>
+    <VSToolsPath Condition="'$(VSToolsPath)' == ''">$(MSBuildExtensionsPath32)\Microsoft\VisualStudio\v$(VisualStudioVersion)</VSToolsPath>
+  </PropertyGroup>
+  <Import Project="$(VSToolsPath)\DNX\Microsoft.DNX.Props" Condition="'$(VSToolsPath)' != ''" />
+  <PropertyGroup Label="Globals">
+    <ProjectGuid>947dd232-8d9b-4b78-9c6a-94f807d22222</ProjectGuid>
+    <RootNamespace>TestProjectToProjectDependencies</RootNamespace>
+    <BaseIntermediateOutputPath Condition="'$(BaseIntermediateOutputPath)'=='' ">..\..\artifacts\obj\$(MSBuildProjectName)</BaseIntermediateOutputPath>
+    <OutputPath Condition="'$(OutputPath)'=='' ">..\..\artifacts\bin\$(MSBuildProjectName)\</OutputPath>
+  </PropertyGroup>
+
+  <PropertyGroup>
+    <SchemaVersion>2.0</SchemaVersion>
+  </PropertyGroup>
+  <Import Project="$(VSToolsPath)\DNX\Microsoft.DNX.targets" Condition="'$(VSToolsPath)' != ''" />
+</Project>

test/TestProjects/TestProjectToProjectDependencies/global.json

@@ -0,0 +1,3 @@
+{
+    "projects": [ "src" ]
+}

test/TestProjects/TestProjectToProjectDependencies/src/L0/NuGet.Config

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="utf-8"?>
+<configuration>
+  <packageSources>
+    <!--To inherit the global NuGet package sources remove the <clear/> line below -->
+    <clear />
+    <add key="dotnet-core" value="https://www.myget.org/F/dotnet-core/api/v3/index.json" />
+    <add key="api.nuget.org" value="https://api.nuget.org/v3/index.json" />
+  </packageSources>
+</configuration>

test/TestProjects/TestProjectToProjectDependencies/src/L0/Program.cs

@@ -0,0 +1,12 @@
+using System;
+
+namespace ConsoleApplication
+{
+    public class L0
+    {
+        public static void Main(string[] args)
+        {
+            Console.WriteLine("L0 " + L11.Value() + L12.Value());
+        }
+    }
+}

test/TestProjects/TestProjectToProjectDependencies/src/L0/project.json

@@ -0,0 +1,17 @@
+{
+    "version": "1.0.0-*",
+    "compilationOptions": {
+        "emitEntryPoint": true
+    },
+
+    "dependencies": {
+        "L11": "1.0.0-*",
+        "L12": "1.0.0-*",
+        
+        "NETStandard.Library": "1.0.0-rc2-23704"
+    },
+
+    "frameworks": {
+        "dnxcore50": { }
+    }
+}

test/TestProjects/TestProjectToProjectDependencies/src/L11/NuGet.Config

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="utf-8"?>
+<configuration>
+  <packageSources>
+    <!--To inherit the global NuGet package sources remove the <clear/> line below -->
+    <clear />
+    <add key="dotnet-core" value="https://www.myget.org/F/dotnet-core/api/v3/index.json" />
+    <add key="api.nuget.org" value="https://api.nuget.org/v3/index.json" />
+  </packageSources>
+</configuration>

test/TestProjects/TestProjectToProjectDependencies/src/L11/Program.cs

@@ -0,0 +1,12 @@
+using System;
+
+namespace ConsoleApplication
+{
+    public class L11
+    {
+        public static string Value()
+        {
+            return "L11 " + L12.Value() + L21.Value();
+        }
+    }
+}

test/TestProjects/TestProjectToProjectDependencies/src/L11/project.json

@@ -0,0 +1,14 @@
+{
+    "version": "1.0.0-*",
+
+    "dependencies": {
+		"L12": "1.0.0-*",
+		"L21": "1.0.0-*",
+
+        "NETStandard.Library": "1.0.0-rc2-23704"
+    },
+
+    "frameworks": {
+        "dnxcore50": { }
+    }
+}

test/TestProjects/TestProjectToProjectDependencies/src/L12/NuGet.Config

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="utf-8"?>
+<configuration>
+  <packageSources>
+    <!--To inherit the global NuGet package sources remove the <clear/> line below -->
+    <clear />
+    <add key="dotnet-core" value="https://www.myget.org/F/dotnet-core/api/v3/index.json" />
+    <add key="api.nuget.org" value="https://api.nuget.org/v3/index.json" />
+  </packageSources>
+</configuration>

test/TestProjects/TestProjectToProjectDependencies/src/L12/Program.cs

@@ -0,0 +1,12 @@
+using System;
+
+namespace ConsoleApplication
+{
+    public class L12
+    {
+        public static string Value()
+        {
+            return "L12 " + L22.Value();
+        }
+    }
+}

test/TestProjects/TestProjectToProjectDependencies/src/L12/project.json

@@ -0,0 +1,13 @@
+{
+    "version": "1.0.0-*",
+
+    "dependencies": {
+        "L22": "1.0.0-*",
+
+        "NETStandard.Library": "1.0.0-rc2-23704"
+    },
+
+    "frameworks": {
+        "dnxcore50": { }
+    }
+}

test/TestProjects/TestProjectToProjectDependencies/src/L21/NuGet.Config

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="utf-8"?>
+<configuration>
+  <packageSources>
+    <!--To inherit the global NuGet package sources remove the <clear/> line below -->
+    <clear />
+    <add key="dotnet-core" value="https://www.myget.org/F/dotnet-core/api/v3/index.json" />
+    <add key="api.nuget.org" value="https://api.nuget.org/v3/index.json" />
+  </packageSources>
+</configuration>

test/TestProjects/TestProjectToProjectDependencies/src/L21/Program.cs

@@ -0,0 +1,12 @@
+using System;
+
+namespace ConsoleApplication
+{
+    public class L21
+    {
+        public static string Value()
+        {
+            return "L21 ";
+        }
+    }
+}

test/TestProjects/TestProjectToProjectDependencies/src/L21/project.json

@@ -0,0 +1,11 @@
+{
+    "version": "1.0.0-*",
+
+    "dependencies": {
+        "NETStandard.Library": "1.0.0-rc2-23704"
+    },
+
+    "frameworks": {
+        "dnxcore50": { }
+    }
+}

test/TestProjects/TestProjectToProjectDependencies/src/L22/NuGet.Config

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="utf-8"?>
+<configuration>
+  <packageSources>
+    <!--To inherit the global NuGet package sources remove the <clear/> line below -->
+    <clear />
+    <add key="dotnet-core" value="https://www.myget.org/F/dotnet-core/api/v3/index.json" />
+    <add key="api.nuget.org" value="https://api.nuget.org/v3/index.json" />
+  </packageSources>
+</configuration>

test/TestProjects/TestProjectToProjectDependencies/src/L22/Program.cs

@@ -0,0 +1,12 @@
+using System;
+
+namespace ConsoleApplication
+{
+    public class L22
+    {
+        public static string Value()
+        {
+            return "L22 ";
+        }
+    }
+}

test/TestProjects/TestProjectToProjectDependencies/src/L22/project.json

@@ -0,0 +1,11 @@
+{
+    "version": "1.0.0-*",
+
+    "dependencies": {
+        "NETStandard.Library": "1.0.0-rc2-23704"
+    },
+
+    "frameworks": {
+        "dnxcore50": { }
+    }
+}

test/TestProjects/TestSimpleIncrementalApp/NuGet.Config

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="utf-8"?>
+<configuration>
+  <packageSources>
+    <!--To inherit the global NuGet package sources remove the <clear/> line below -->
+    <clear />
+    <add key="dotnet-core" value="https://www.myget.org/F/dotnet-core/api/v3/index.json" />
+    <add key="api.nuget.org" value="https://api.nuget.org/v3/index.json" />
+  </packageSources>
+</configuration>

test/TestProjects/TestSimpleIncrementalApp/Program.cs

@@ -0,0 +1,12 @@
+using System;
+
+namespace ConsoleApplication
+{
+    public class Program
+    {
+        public static void Main(string[] args)
+        {
+            Console.WriteLine("Hello World!");
+        }
+    }
+}

test/TestProjects/TestSimpleIncrementalApp/TestApp.xproj

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="14.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup>
+    <VisualStudioVersion Condition="'$(VisualStudioVersion)' == ''">14.0</VisualStudioVersion>
+    <VSToolsPath Condition="'$(VSToolsPath)' == ''">$(MSBuildExtensionsPath32)\Microsoft\VisualStudio\v$(VisualStudioVersion)</VSToolsPath>
+  </PropertyGroup>
+
+  <Import Project="$(VSToolsPath)\DNX\Microsoft.DNX.Props" Condition="'$(VSToolsPath)' != ''" />
+  <PropertyGroup Label="Globals">
+    <ProjectGuid>58808bbc-371e-47d6-a3d0-4902145edaaa</ProjectGuid>
+    <RootNamespace>TestSimpleIncrementalApp</RootNamespace>
+    <BaseIntermediateOutputPath Condition="'$(BaseIntermediateOutputPath)'=='' ">..\..\artifacts\obj\$(MSBuildProjectName)</BaseIntermediateOutputPath>
+    <OutputPath Condition="'$(OutputPath)'=='' ">..\..\artifacts\bin\$(MSBuildProjectName)\</OutputPath>
+  </PropertyGroup>
+
+  <PropertyGroup>
+    <SchemaVersion>2.0</SchemaVersion>
+  </PropertyGroup>
+  <Import Project="$(VSToolsPath)\DNX\Microsoft.DNX.targets" Condition="'$(VSToolsPath)' != ''" />
+</Project>

test/TestProjects/TestSimpleIncrementalApp/project.json

@@ -0,0 +1,15 @@
+{
+    "version": "1.0.0-*",
+    "compilationOptions": {
+        "emitEntryPoint": true,
+        "xmlDoc": true
+    },
+
+    "dependencies": {
+        "NETStandard.Library": "1.0.0-rc2-23704"
+    },
+
+    "frameworks": {
+        "dnxcore50": { }
+    }
+}