Rename test projects

test/dotnet-build.Tests/BuildProjectToProjectTests.cs

@@ -0,0 +1,77 @@
+// 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" };
+
+        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);
+        }
+    }
+}