1 files changed, 93 insertions, 0 deletions
diff --git a/tests/Jellyfin.Server.Implementations.Tests/Users/UserManagerLockHelperTests.cs b/tests/Jellyfin.Server.Implementations.Tests/Users/UserManagerLockHelperTests.cs
new file mode 100644
index 0000000000..8149938b4d
--- /dev/null
+++ b/tests/Jellyfin.Server.Implementations.Tests/Users/UserManagerLockHelperTests.cs
@@ -0,0 +1,93 @@
+using System;
+using System.Threading.Tasks;
+using Jellyfin.Server.Implementations.Users;
+using Xunit;
+
+namespace Jellyfin.Server.Implementations.Tests.Users
+{
+    public class UserManagerLockHelperTests
+    {
+        [Fact]
+        public async Task LockAsync_WhenNested_DoesNotAcquireSecondLockAndRestoresStateOnDispose()
+        {
+            UserManager.LockHelper.IsNestedLock.Value = 0;
+            using var helper = new UserManager.LockHelper();
+            var key = Guid.NewGuid();
+
+            Assert.True(helper.ShouldLock());
+
+            var outerHandle = await helper.LockAsync(key);
+            Assert.False(helper.ShouldLock());
+
+            var innerHandle = await helper.LockAsync(key);
+            Assert.False(helper.ShouldLock());
+
+            innerHandle.Dispose();
+            Assert.False(helper.ShouldLock());
+
+            outerHandle.Dispose();
+            Assert.True(helper.ShouldLock());
+        }
+
+        [Fact]
+        public async Task LockAsync_WithSameKey_BlocksSecondLockUntilFirstIsReleased()
+        {
+            UserManager.LockHelper.IsNestedLock.Value = 0;
+            using var helper = new UserManager.LockHelper();
+            var key = Guid.NewGuid();
+
+            var firstAcquired = new TaskCompletionSource<bool>(TaskCreationOptions.RunContinuationsAsynchronously);
+            var releaseFirst = new TaskCompletionSource<bool>(TaskCreationOptions.RunContinuationsAsynchronously);
+            var secondEntered = false;
+
+            var firstTask = Task.Run(
+                async () =>
+                {
+                    using var firstHandle = await helper.LockAsync(key);
+                    firstAcquired.SetResult(true);
+                    await releaseFirst.Task;
+                },
+                TestContext.Current.CancellationToken);
+
+            await firstAcquired.Task;
+
+            var secondTask = Task.Run(
+                async () =>
+                {
+                    using var secondHandle = await helper.LockAsync(key);
+                    secondEntered = true;
+                },
+                TestContext.Current.CancellationToken);
+
+            await Task.Delay(100, TestContext.Current.CancellationToken);
+            Assert.False(secondEntered);
+
+            releaseFirst.SetResult(true);
+
+            await Task.WhenAll(firstTask, secondTask);
+            Assert.True(secondEntered);
+        }
+
+        [Fact]
+        public async Task LockAsync_WhenDisposed_ThrowsObjectDisposedException()
+        {
+            UserManager.LockHelper.IsNestedLock.Value = 0;
+            using var helper = new UserManager.LockHelper();
+            helper.Dispose();
+
+            await Assert.ThrowsAsync<ObjectDisposedException>(async () => await helper.LockAsync(Guid.NewGuid()));
+        }
+
+        [Fact]
+        public void Dispose_WhenCalledMultipleTimes_DoesNotThrow()
+        {
+            UserManager.LockHelper.IsNestedLock.Value = 0;
+            using var helper = new UserManager.LockHelper();
+
+            helper.Dispose();
+            var ex = Record.Exception(() => helper.Dispose());
+
+            Assert.Null(ex);
+        }
+    }
+}