using System;
using System.Diagnostics;
using System.Threading;

using NUnit.Framework;

using Python.Runtime;

namespace Python.EmbeddingTest;

public class Events
{
 [OneTimeSetUp]
 public void SetUp()
 {
 PythonEngine.Initialize();
 }

 [OneTimeTearDown]
 public void Dispose()
 {
 PythonEngine.Shutdown();
 }

 [Test]
 public void UsingDoesNotLeak()
 {
 using var scope = Py.CreateScope();
 scope.Exec(@"
import gc

from Python.EmbeddingTest import ClassWithEventHandler

def event_handler():
 pass

for _ in range(2000):
 example = ClassWithEventHandler()
 example.LeakEvent += event_handler
 example.LeakEvent -= event_handler
 del example

gc.collect()
");
 Runtime.Runtime.TryCollectingGarbage(10);
 Assert.AreEqual(0, ClassWithEventHandler.alive);
 }
}

public class ClassWithEventHandler
{
 internal static int alive;

 public event EventHandler LeakEvent;
 private Array arr; // dummy array to exacerbate memory leak

 public ClassWithEventHandler()
 {
 Interlocked.Increment(ref alive);
 this.arr = new int[800];
 }

 ~ClassWithEventHandler()
 {
 Interlocked.Decrement(ref alive);
 }
}