Severity: Info
File: tests/Servy.Manager.UnitTests/Utils/LogTailerTests.cs lines 76–89

Description:
RunFromPosition_ShouldHandleFileRotation coordinates with the SUT exclusively via fixed Task.Delay:

// Wait for the tailer to actually enter its inner loop
await Task.Delay(300, TestContext.Current.CancellationToken);

// Simulate Rotation: Truncate and write fresh content …
using (var fs = new FileStream(initialPath, FileMode.Truncate, …))
using (var sw = new StreamWriter(fs) { AutoFlush = true })
{
    await sw.WriteLineAsync("ROTATED_CONTENT");
}

// Give the polling loop (150ms) and ReadLineAsync enough time to process the truncation
await Task.Delay(1000, TestContext.Current.CancellationToken);

Both delays are tuned to the current polling interval (150ms). The comment acknowledges the timing assumption. On a slow CI agent, a noisy VM, or under parallel-test load, 300ms may not be enough for the tailer to enter its inner loop; 1000ms may not be enough for the poll + ReadLineAsync to catch the truncated file. Failure mode: the test asserts Assert.Contains(capturedLines, …) on an empty list — red CI for reasons unrelated to product behaviour.

Suggested fix:
Replace both delays with deterministic waits:

• For "enter inner loop": have LogTailer expose a TaskCompletionSource signalling "first poll started" (an internal or testing-only property), and await that from the test.
• For "poll has observed rotation": wait on capturedLines reaching count >= 1 via a polling helper with a generous timeout (e.g., 10s) that exits as soon as the assertion becomes true, rather than sleeping unconditionally for 1000ms.

static async Task WaitUntilAsync(Func<bool> predicate, TimeSpan timeout) {
    var deadline = DateTime.UtcNow + timeout;
    while (DateTime.UtcNow < deadline) {
        if (predicate()) return;
        await Task.Delay(50);
    }
    throw new TimeoutException();
}

That pattern keeps the test fast on healthy agents and tolerant on slow ones.