C#: Add unit tests for runtime version fetching.

Author: michaelnebel

csharp/extractor/Semmle.Extraction.CSharp.Standalone/DotNet.cs

@@ -5,10 +5,18 @@
 
 namespace Semmle.BuildAnalyser
 {
+    internal interface IDotNet
+    {
+        bool RestoreToDirectory(string project, string directory);
+        bool New(string folder);
+        bool AddPackage(string folder, string package);
+        public IList<string> GetListedRuntimes();
+    }
+
     /// <summary>
     /// Utilities to run the "dotnet" command.
     /// </summary>
-    internal class DotNet
+    internal class DotNet : IDotNet
     {
         private const string dotnet = "dotnet";
         private readonly ProgressMonitor progressMonitor;

csharp/extractor/Semmle.Extraction.CSharp.Standalone/Properties/AssemblyInfo.cs

@@ -1,4 +1,5 @@
 using System.Reflection;
+using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 
 // General Information about an assembly is controlled through the following
@@ -13,6 +14,9 @@
 [assembly: AssemblyTrademark("")]
 [assembly: AssemblyCulture("")]
 
+// Expose internals for testing purposes.
+[assembly: InternalsVisibleTo("Semmle.Extraction.Tests")]
+
 // Setting ComVisible to false makes the types in this assembly not visible
 // to COM components.  If you need to access a type in this assembly from
 // COM, set the ComVisible attribute to true on that type.

csharp/extractor/Semmle.Extraction.CSharp.Standalone/Runtime.cs

@@ -17,12 +17,12 @@ internal partial class Runtime
         private const string netCoreApp = "Microsoft.NETCore.App";
         private const string aspNetCoreApp = "Microsoft.AspNetCore.App";
 
-        private readonly DotNet dotNet;
+        private readonly IDotNet dotNet;
         private static string ExecutingRuntime => RuntimeEnvironment.GetRuntimeDirectory();
 
-        public Runtime(DotNet dotNet) => this.dotNet = dotNet;
+        public Runtime(IDotNet dotNet) => this.dotNet = dotNet;
 
-        private sealed class RuntimeVersion : IComparable<RuntimeVersion>
+        internal sealed class RuntimeVersion : IComparable<RuntimeVersion>
         {
             private readonly string dir;
             private Version Version { get; }
@@ -97,7 +97,10 @@ private static Dictionary<string, RuntimeVersion> ParseRuntimes(IList<string> li
             return runtimes;
         }
 
-        private Dictionary<string, RuntimeVersion> GetNewestRuntimes()
+        /// <summary>
+        /// Returns a dictionary mapping runtimes to their newest version.
+        /// </summary>
+        internal Dictionary<string, RuntimeVersion> GetNewestRuntimes()
         {
             var listed = dotNet.GetListedRuntimes();
             return ParseRuntimes(listed);

csharp/extractor/Semmle.Extraction.Tests/Runtime.cs

@@ -0,0 +1,78 @@
+using Xunit;
+using System.Collections.Generic;
+using Semmle.BuildAnalyser;
+using Semmle.Extraction.CSharp.Standalone;
+
+namespace Semmle.Extraction.Tests
+{
+    internal class DotNetStub : IDotNet
+    {
+        private readonly IList<string> runtimes;
+
+        public DotNetStub(IList<string> runtimes) => this.runtimes = runtimes;
+
+        public bool AddPackage(string folder, string package) => true;
+
+        public bool New(string folder) => true;
+
+        public bool RestoreToDirectory(string project, string directory) => true;
+
+        public IList<string> GetListedRuntimes() => runtimes;
+    }
+
+    public class RuntimeTests
+    {
+        [Fact]
+        public void TestRuntime1()
+        {
+            // Setup
+            var listedRuntimes = new List<string> {
+                "Microsoft.AspNetCore.App 5.0.12 [/path/dotnet/shared/Microsoft.AspNetCore.App]",
+                "Microsoft.AspNetCore.App 6.0.4 [/path/dotnet/shared/Microsoft.AspNetCore.App]",
+                "Microsoft.AspNetCore.App 7.0.0 [/path/dotnet/shared/Microsoft.AspNetCore.App]",
+                "Microsoft.AspNetCore.App 7.0.2 [/path/dotnet/shared/Microsoft.AspNetCore.App]",
+                "Microsoft.NETCore.App 5.0.12 [/path/dotnet/shared/Microsoft.NETCore.App]",
+                "Microsoft.NETCore.App 6.0.4 [/path/dotnet/shared/Microsoft.NETCore.App]",
+                "Microsoft.NETCore.App 7.0.0 [/path/dotnet/shared/Microsoft.NETCore.App]",
+                "Microsoft.NETCore.App 7.0.2 [/path/dotnet/shared/Microsoft.NETCore.App]"
+                };
+            var dotnet = new DotNetStub(listedRuntimes);
+            var runtime = new Runtime(dotnet);
+
+            // Execute
+            var runtimes = runtime.GetNewestRuntimes();
+
+            // Verify
+            Assert.Equal(2, runtimes.Count);
+
+            Assert.True(runtimes.TryGetValue("Microsoft.AspNetCore.App", out var aspNetCoreApp));
+            Assert.Equal("/path/dotnet/shared/Microsoft.AspNetCore.App/7.0.2", aspNetCoreApp.FullPath);
+
+            Assert.True(runtimes.TryGetValue("Microsoft.NETCore.App", out var netCoreApp));
+            Assert.Equal("/path/dotnet/shared/Microsoft.NETCore.App/7.0.2", netCoreApp.FullPath);
+        }
+
+        [Fact]
+        public void TestRuntime2()
+        {
+            // Setup
+            var listedRuntimes = new List<string>
+            {
+                "Microsoft.NETCore.App 7.0.2 [/path/dotnet/shared/Microsoft.NETCore.App]",
+                "Microsoft.NETCore.App 8.0.0-preview.5.23280.8 [/path/dotnet/shared/Microsoft.NETCore.App]",
+                "Microsoft.NETCore.App 8.0.0-preview.5.43280.8 [/path/dotnet/shared/Microsoft.NETCore.App]"
+            };
+            var dotnet = new DotNetStub(listedRuntimes);
+            var runtime = new Runtime(dotnet);
+
+            // Execute
+            var runtimes = runtime.GetNewestRuntimes();
+
+            // Verify
+            Assert.Single(runtimes);
+
+            Assert.True(runtimes.TryGetValue("Microsoft.NETCore.App", out var netCoreApp));
+            Assert.Equal("/path/dotnet/shared/Microsoft.NETCore.App/8.0.0-preview.5.43280.8", netCoreApp.FullPath);
+        }
+    }
+}