[test] Mono.Debugger.Soft test for async I/O tasks

2 files changed, 43 insertions, 0 deletions

diff --git a/mcs/class/Mono.Debugger.Soft/Test/dtest-app.cs b/mcs/class/Mono.Debugger.Soft/Test/dtest-app.cs
index 4b9d569b1ad..f9d5df5af7f 100644
--- a/mcs/class/Mono.Debugger.Soft/Test/dtest-app.cs
+++ b/mcs/class/Mono.Debugger.Soft/Test/dtest-app.cs
@@ -9,6 +9,7 @@ using System.Reflection;
 using System.Reflection.Emit;
 using System.Diagnostics;
 using System.Threading;
+using System.Threading.Tasks;
 using System.Collections.Generic;
 using System.Linq;
 
@@ -311,6 +312,10 @@ public class Tests : TestsBase, ITest2
 			wait_one ();
 			return 0;
 		}
+		if (args.Length >0 && args [0] == "threadpool-io") {
+			threadpool_io ();
+			return 0;
+		}
 		breakpoints ();
 		single_stepping ();
 		arguments ();
@@ -1541,6 +1546,20 @@ public class Tests : TestsBase, ITest2
 	public override string virtual_method () {
 		return "V2";
 	}
+
+	[MethodImplAttribute (MethodImplOptions.NoInlining)]
+	public static void threadpool_io () {
+		Task<int> t = Task.Run (async () => {
+			var wc = new System.Net.WebClient ();
+			string filename = System.IO.Path.GetTempFileName ();
+
+			var dl = wc.DownloadFileTaskAsync ("http://www.mono-project.com/", filename);
+			await dl;
+			System.IO.File.Delete (filename);
+			return 1;
+			});
+		var n = t.Result;
+	}
 }
 
 class TypeLoadClass {
diff --git a/mcs/class/Mono.Debugger.Soft/Test/dtest.cs b/mcs/class/Mono.Debugger.Soft/Test/dtest.cs
index c0af12cb38a..6407b9eae71 100644
--- a/mcs/class/Mono.Debugger.Soft/Test/dtest.cs
+++ b/mcs/class/Mono.Debugger.Soft/Test/dtest.cs
@@ -4035,6 +4035,30 @@ public class DebuggerTests
 		// Make sure we are still in the cctor
 		Assert.AreEqual (".cctor", e.Thread.GetFrames ()[0].Location.Method.Name);
 	}
+
+	[Test]
+	public void ThreadpoolIOsinglestep () {
+		// This is a regression test for #42625.
+		// It tests the interaction (particularly in coop GC of
+		// the threadpool I/O mechanism and the soft debugger.
+		Start (new string [] { "dtest-app.exe", "threadpool-io" });
+
+		Event e = run_until ("threadpool_io");
+		var req = create_step (e);
+		req.Enable ();
+
+		// step to start the task
+		e = step_once ();
+		
+		req.Disable ();
+
+		// run until completion of the test method
+		e = step_out ();
+
+		vm.Resume ();
+
+		vm.Suspend ();
+	}
 }
 
 }