Merge pull request github#14325 from michaelnebel/csharp/stubgentests

C#: Add a couple of stub generator unit tests

Author: michaelnebel

csharp/extractor/Semmle.Extraction.CSharp.StubGenerator/IRelevantSymbol.cs

@@ -0,0 +1,9 @@
+using Microsoft.CodeAnalysis;
+
+namespace Semmle.Extraction.CSharp.StubGenerator;
+
+internal interface IRelevantSymbol
+{
+    bool IsRelevantNamedType(INamedTypeSymbol symbol);
+    bool IsRelevantNamespace(INamespaceSymbol symbol);
+}

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

@@ -0,0 +1,39 @@
+using System.Reflection;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+// General Information about an assembly is controlled through the following
+// set of attributes. Change these attribute values to modify the information
+// associated with an assembly.
+[assembly: AssemblyTitle("Semmle.Extraction.CSharp.StubGenerator")]
+[assembly: AssemblyDescription("Stub generator for C#")]
+[assembly: AssemblyConfiguration("")]
+[assembly: AssemblyCompany("")]
+[assembly: AssemblyProduct("Semmle.Extraction.CSharp.StubGenerator")]
+[assembly: AssemblyCopyright("Copyright ©  2023")]
+[assembly: AssemblyTrademark("")]
+[assembly: AssemblyCulture("")]
+
+// 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.
+[assembly: ComVisible(false)]
+
+// The following GUID is for the ID of the typelib if this project is exposed to COM
+[assembly: Guid("6d55ca39-615a-4c1b-a648-a4010995e1ea")]
+
+// Expose internals for testing purposes.
+[assembly: InternalsVisibleTo("Semmle.Extraction.Tests")]
+
+// Version information for an assembly consists of the following four values:
+//
+//      Major Version
+//      Minor Version
+//      Build Number
+//      Revision
+//
+// You can specify all the values or you can default the Build and Revision Numbers
+// by using the '*' as shown below:
+// [assembly: AssemblyVersion("1.0.*")]
+[assembly: AssemblyVersion("1.0.0.0")]
+[assembly: AssemblyFileVersion("1.0.0.0")]

csharp/extractor/Semmle.Extraction.CSharp.StubGenerator/RelevantSymbol.cs

@@ -1,13 +1,10 @@
 using System.Linq;
-
 using Microsoft.CodeAnalysis;
-using Microsoft.CodeAnalysis.CSharp;
-
 using Semmle.Util;
 
 namespace Semmle.Extraction.CSharp.StubGenerator;
 
-internal class RelevantSymbol
+internal class RelevantSymbol : IRelevantSymbol
 {
     private readonly IAssemblySymbol assembly;
     private readonly MemoizedFunc<INamedTypeSymbol, bool> isRelevantNamedType;

csharp/extractor/Semmle.Extraction.CSharp.StubGenerator/StubVisitor.cs

@@ -12,9 +12,9 @@ namespace Semmle.Extraction.CSharp.StubGenerator;
 internal sealed class StubVisitor : SymbolVisitor
 {
     private readonly TextWriter stubWriter;
-    private readonly RelevantSymbol relevantSymbol;
+    private readonly IRelevantSymbol relevantSymbol;
 
-    public StubVisitor(TextWriter stubWriter, RelevantSymbol relevantSymbol)
+    public StubVisitor(TextWriter stubWriter, IRelevantSymbol relevantSymbol)
     {
         this.stubWriter = stubWriter;
         this.relevantSymbol = relevantSymbol;

csharp/extractor/Semmle.Extraction.Tests/Semmle.Extraction.Tests.csproj

@@ -16,6 +16,7 @@
 		<PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.4.0" />
 	</ItemGroup>
 	<ItemGroup>
+		<ProjectReference Include="..\Semmle.Extraction.CSharp.StubGenerator\Semmle.Extraction.CSharp.StubGenerator.csproj" />
 		<ProjectReference Include="..\Semmle.Extraction.CSharp.Standalone\Semmle.Extraction.CSharp.Standalone.csproj" />
 		<ProjectReference Include="..\Semmle.Extraction.CSharp\Semmle.Extraction.CSharp.csproj" />
 		<ProjectReference Include="..\Semmle.Extraction\Semmle.Extraction.csproj" />

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

@@ -0,0 +1,74 @@
+using Xunit;
+using System.IO;
+using System.Text;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp;
+using Semmle.Extraction.CSharp.StubGenerator;
+
+namespace Semmle.Extraction.Tests;
+/// <summary>
+/// Tests for the stub generator.
+/// 
+/// These tests can be used to more easily step debug the stub generator SymbolVisitor.
+/// </summary>
+public class StubGeneratorTests
+{
+    [Fact]
+    public void StubGeneratorFieldTest()
+    {
+        // Setup
+        const string source = @"
+public class MyTest {
+    public static readonly int MyField1;
+    public const string MyField2 = ""hello"";
+    }
+";
+
+        // Execute
+        var stub = GenerateStub(source);
+
+        // Verify
+        const string expected = @"public class MyTest {
+public static readonly int MyField1;
+public const string MyField2 = default;
+}
+";
+        Assert.Equal(expected, stub);
+    }
+
+    [Fact]
+    public void StubGeneratorMethodTest()
+    {
+        // Setup
+        const string source = @"
+public class MyTest {
+    public int M1(string arg1) { return 0;}
+}";
+
+        // Execute
+        var stub = GenerateStub(source);
+
+        // Verify
+        const string expected = @"public class MyTest {
+public int M1(string arg1) => throw null;
+}
+";
+        Assert.Equal(expected, stub);
+    }
+
+    private static string GenerateStub(string source)
+    {
+        var st = CSharpSyntaxTree.ParseText(source);
+        var compilation = CSharpCompilation.Create(null, new[] { st });
+        var sb = new StringBuilder();
+        var visitor = new StubVisitor(new StringWriter(sb), new RelevantSymbolStub());
+        compilation.GlobalNamespace.Accept(visitor);
+        return sb.ToString();
+    }
+
+    private class RelevantSymbolStub : IRelevantSymbol
+    {
+        public bool IsRelevantNamedType(INamedTypeSymbol symbol) => true;
+        public bool IsRelevantNamespace(INamespaceSymbol symbol) => true;
+    }
+}