thomhurst · thomhurst · Jan 27, 2026 · Jan 27, 2026
diff --git a/TUnit.Assertions.Tests/ThreadAssertionTests.cs b/TUnit.Assertions.Tests/ThreadAssertionTests.cs
@@ -1,5 +1,4 @@
 using TUnit.Assertions.Extensions;
-using TUnit.Assertions.Extensions;

 namespace TUnit.Assertions.Tests;

@@ -15,24 +14,25 @@ public async Task Test_Thread_IsAlive()
    [Test]
    public async Task Test_Thread_IsAlive_NewThread()
    {
-        var signal = new ManualResetEventSlim(false);
-        Thread? thread = null;
+        var startSignal = new ManualResetEventSlim(false);
+        var completeSignal = new ManualResetEventSlim(false);

-        thread = new Thread(() =>
+        var thread = new Thread(() =>
        {
-            signal.Set();
-            Thread.Sleep(100);
+            startSignal.Set();
+            completeSignal.Wait();
        });

        thread.Start();
-        signal.Wait();
+        startSignal.Wait();

        try
        {
            await Assert.That(thread).IsAlive();
        }
        finally
        {
+            completeSignal.Set();
            thread.Join();
        }
    }
@@ -61,19 +61,28 @@ public async Task Test_Thread_IsBackground()
    [Test]
    public async Task Test_Thread_IsBackground_Started()
    {
-        var thread = new Thread(() => Thread.Sleep(100))
+        var startSignal = new ManualResetEventSlim(false);
+        var completeSignal = new ManualResetEventSlim(false);
+
+        var thread = new Thread(() =>
+        {
+            startSignal.Set();
+            completeSignal.Wait();
+        })
        {
            IsBackground = true
        };

        thread.Start();
+        startSignal.Wait();

        try
        {
            await Assert.That(thread).IsBackground();
        }
        finally
        {
+            completeSignal.Set();
            thread.Join();
        }
    }
@@ -129,15 +138,25 @@ public async Task Test_Thread_IsNotThreadPoolThread()
    [Test]
    public async Task Test_Thread_IsNotThreadPoolThread_NewThread()
    {
-        var thread = new Thread(() => Thread.Sleep(50));
+        var startSignal = new ManualResetEventSlim(false);
+        var completeSignal = new ManualResetEventSlim(false);
+
+        var thread = new Thread(() =>
+        {
+            startSignal.Set();
+            completeSignal.Wait();
+        });
+
        thread.Start();
+        startSignal.Wait();

        try
        {
            await Assert.That(thread).IsNotThreadPoolThread();
        }
        finally
        {
+            completeSignal.Set();
            thread.Join();
        }
    }