Unit tests for the logger command-line argument when telemetry is enabled or disabled

test/dotnet-msbuild.Tests/GivenDotnetMSBuildBuildsProjects.cs

@@ -1,9 +1,17 @@
 // 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.Linq;
+using System.Linq.Expressions;
+using System.Reflection;
 using FluentAssertions;
+using Microsoft.DotNet.Configurer;
+using Microsoft.DotNet.Tools.MSBuild;
 using Microsoft.DotNet.Tools.Test.Utilities;
+using NuGet.Protocol;
 using Xunit;
+using MSBuildCommand = Microsoft.DotNet.Tools.Test.Utilities.MSBuildCommand;
 
 namespace Microsoft.DotNet.Cli.MSBuild.Tests
 {
@@ -69,5 +77,60 @@ namespace Microsoft.DotNet.Cli.MSBuild.Tests
             }
         }
 
+        [Fact]
+        public void WhenTelemetryIsEnabledTheLoggerIsAddedToTheCommandLine()
+        {
+            string[] allArgs = GetArgsForMSBuild(() => true);
+
+            allArgs.Should().NotBeNull();
+
+            allArgs.Should().Contain(value => value.StartsWith("\"/Logger:"), "The MSBuild logger argument should be specified when telemetry is enabled.");
+        }
+
+        [Fact]
+        public void WhenTelemetryIsDisabledTheLoggerIsNotAddedToTheCommandLine()
+        {
+            string[] allArgs = GetArgsForMSBuild(() => false);
+
+            allArgs.Should().NotBeNull();
+
+            allArgs.Should().NotContain(value => value.IndexOf("/Logger", StringComparison.OrdinalIgnoreCase) >= 0, $"The MSBuild logger argument should not be specified when telemetry is disabled.");
+        }
+
+        private string[] GetArgsForMSBuild(Func<bool> sentinelExists)
+        {
+            Telemetry telemetry = new Telemetry(new MockNuGetCacheSentinel(sentinelExists));
+
+            MSBuildForwardingApp msBuildForwardingApp = new MSBuildForwardingApp(Enumerable.Empty<string>());
+
+            FieldInfo forwardingAppFieldInfo = msBuildForwardingApp.GetType().GetField("_forwardingApp", BindingFlags.Instance | BindingFlags.NonPublic);
+
+            ForwardingApp forwardingApp = forwardingAppFieldInfo?.GetValue(msBuildForwardingApp) as ForwardingApp;
+
+            FieldInfo allArgsFieldinfo = forwardingApp?.GetType().GetField("_allArgs", BindingFlags.Instance | BindingFlags.NonPublic);
+
+            return allArgsFieldinfo?.GetValue(forwardingApp) as string[];
+        }
+    }
+
+    public sealed class MockNuGetCacheSentinel : INuGetCacheSentinel
+    {
+        private readonly Func<bool> _exists;
+
+        public MockNuGetCacheSentinel(Func<bool> exists = null)
+        {
+            _exists = exists ?? (() => true);
+        }
+        public void Dispose()
+        {
+        }
+
+        public bool InProgressSentinelAlreadyExists() => false;
+
+        public bool Exists() => _exists();
+
+        public void CreateIfNotExists()
+        {
+        }
     }
 }

test/dotnet-msbuild.Tests/project.json

@@ -10,7 +10,10 @@
       "target": "project"
     },
     "xunit": "2.2.0-beta3-build3330",
-    "dotnet-test-xunit": "1.0.0-rc2-350904-49"
+    "dotnet-test-xunit": "1.0.0-rc2-350904-49",
+    "dotnet": {
+      "target": "project"
+    }
   },
   "frameworks": {
     "netcoreapp1.0": {