Alternative to SemaphoreSlim added

PerfectNumbers.Core.Tests/PollingSemaphoreTests.cs

@@ -0,0 +1,56 @@
+using FluentAssertions;
+using PerfectNumbers.Core;
+using Xunit;
+
+namespace PerfectNumbers.Core.Tests;
+
+public class PollingSemaphoreTests
+{
+    [Fact]
+    [Trait("Category", "Fast")]
+    public void TryEnter_AllowsConfiguredConcurrency()
+    {
+        var semaphore = new PollingSemaphore(2, TimeSpan.Zero);
+
+        semaphore.TryEnter().Should().BeTrue();
+        semaphore.TryEnter().Should().BeTrue();
+        semaphore.TryEnter().Should().BeFalse();
+
+        semaphore.Release();
+        semaphore.Release();
+    }
+
+    [Fact]
+    [Trait("Category", "Fast")]
+    public async Task Wait_BlocksUntilRelease()
+    {
+        var semaphore = new PollingSemaphore(1, TimeSpan.FromMilliseconds(1));
+
+        semaphore.TryEnter().Should().BeTrue();
+
+        Task<bool> waiter = Task.Run(() => semaphore.Wait(TimeSpan.FromMilliseconds(200)));
+
+        await Task.Delay(20);
+        semaphore.Release();
+
+        bool entered = await waiter;
+        entered.Should().BeTrue();
+
+        semaphore.Release();
+    }
+
+    [Fact]
+    [Trait("Category", "Fast")]
+    public void Wait_ReturnsFalseWhenTimeoutHits()
+    {
+        var semaphore = new PollingSemaphore(1, TimeSpan.FromMilliseconds(2));
+
+        semaphore.TryEnter().Should().BeTrue();
+
+        bool acquired = semaphore.Wait(TimeSpan.FromMilliseconds(30));
+
+        acquired.Should().BeFalse();
+
+        semaphore.Release();
+    }
+}