Debugging unit tests that fail due to a StackOverflow exception

Question

Whenever a unit test fails due to a StackOverflowException the unit test process immediately exits - the only way to find out what happened (that I am aware of) is to debug a crash dump of the unit test process obtained by following the steps found here

• Collecting User-Mode Dumps

What is the easiest way of getting the name of the unit test that was running at the time that the StackOverflowException was thrown? Even when debugging the unit test I'm struggling to find the name of the current unit test as its at the bottom of the stack and Visual Studio wont' shown the entire stack in the debugging window because its too large.

Is there some way to find out which unit test failed without collecting and debugging crash dumps?

Answer 1

As mentioned in this other question, you can't really catch a stack overflow exception unless you throw it yourself.

So, as a workaround to your problem (not really a solution) you can insert a method call in you code to detect a stack overflow, then throw the exception manually and catch it later.

[TestClass]
public class TestStackOverflowDetection
{
    [TestMethod]
    public void TestDetectStackOverflow()
    {
        try
        {
            InfiniteRecursion();
        }
        catch (StackOverflowException e)
        {
            Debug.WriteLine(e);
        }
    }

    private static int InfiniteRecursion(int i = 0)
    {
        // Insert the following call in all methods that
        // we suspect could be part of an infinite recursion 
        CheckForStackOverflow(); 

        // Force an infinite recursion
        var j = InfiniteRecursion(i) + 1;
        return j;
    }

    private static void CheckForStackOverflow()
    {
        var stack = new System.Diagnostics.StackTrace(true);
        if (stack.FrameCount > 1000) // Set stack limit to 1,000 calls
        {
            // Output last 10 frames in the stack
            foreach (var f in stack.GetFrames().Reverse().Take(30).Reverse())
                Debug.Write("\tat " + f);

            // Throw a stack overflow exception
            throw new StackOverflowException();
        }
    }