Create MsilStructureTests.cs

Author: LPeter1997

src/Draco.Compiler.Tests/CodeGeneration/MsilStructureTests.cs

@@ -0,0 +1,77 @@
+using System.Reflection;
+using Draco.Compiler.Internal;
+
+namespace Draco.Compiler.Tests.CodeGeneration;
+
+public sealed class MsilStructureTests
+{
+    private readonly struct RelayDisposable(Action dispose) : IDisposable
+    {
+        public void Dispose() => dispose();
+    }
+
+    private const BindingFlags AllBindingFlags = BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Static;
+
+    private string? CurrentNamespace => this.namespaceStack.Count == 0
+        ? null
+        : string.Join(".", this.namespaceStack.Reverse());
+    private Type CurrentType => this.typeStack.Peek();
+
+    private Assembly assembly = null!;
+    private readonly Stack<Type> typeStack = new();
+    private readonly Stack<string> namespaceStack = new();
+
+    private void Compile(string source)
+    {
+        this.assembly = TestUtilities.CompileToAssembly(source);
+    }
+
+    private RelayDisposable Ns(string name)
+    {
+        this.namespaceStack.Push(name);
+        return new RelayDisposable(() => this.namespaceStack.Pop());
+    }
+
+    private RelayDisposable C(string name, Func<Type, bool> predicate)
+    {
+        var type = this.typeStack.Count == 0
+            // Look up in root assembly
+            ? this.assembly.GetType(name)
+            // Look up in current type
+            : this.CurrentType.GetNestedType(name, AllBindingFlags);
+
+        Assert.NotNull(type);
+        Assert.Equal(this.CurrentNamespace, type.Namespace);
+        Assert.True(predicate(type));
+        this.typeStack.Push(type);
+
+        return new RelayDisposable(() => this.typeStack.Pop());
+    }
+
+    private RelayDisposable StaticC(string name, Func<Type, bool> predicate) =>
+        this.C(name, t => t.IsAbstract && t.IsSealed && predicate(t));
+
+    private void M(string name, Func<MethodInfo, bool> predicate)
+    {
+        var method = this.CurrentType.GetMethod(name, AllBindingFlags);
+        Assert.NotNull(method);
+        Assert.True(predicate(method));
+    }
+
+    [Fact]
+    public void HelloWorld()
+    {
+        this.Compile("""
+            import System.Console;
+
+            func main() {
+                WriteLine("Hello, World!");
+            }
+            """);
+
+        using (this.StaticC(CompilerConstants.DefaultModuleName, t => !t.IsPublic))
+        {
+            this.M("main", m => !m.IsPublic && m.IsStatic);
+        }
+    }
+}