MbUnit Icarus self-destructs on this test - multithreading

Question

I'm trying to test a multi-threaded IO class using MbUnit. My goal is to have the test fixture constructor execute 3 times, once for each row on the class. Then, for each instance, execute the tests multiple times on parallell threads.
However, Icarus blows up with an 'index out of range' on TaskRunner. I can't get the full stack, it spawns message boxes too fast.
What am I doing wrong, or is this a bug in MbUnit/Gallio?
using System;
using System.Collections.Generic;
using System.Text;
using Gallio.Framework;
using MbUnit.Framework;
using MbUnit.Framework.ContractVerifiers;
using System.IO;
namespace ImageResizer.Plugins.DiskCache.Tests {
[TestFixture]
[Row(0,50,false)]
[Row(0,50,true)]
[Row(8000,100,true)]
public class CustomDiskCacheTest {
public CustomDiskCacheTest(int subfolders, int totalFiles, bool hashModifiedDate) {
char c = System.IO.Path.DirectorySeparatorChar;
string folder = System.IO.Path.GetTempPath().TrimEnd(c) + c + System.IO.Path.GetRandomFileName();
cache = new CustomDiskCache(folder,subfolders,hashModifiedDate);
this.quantity = totalFiles;
for (int i = 0; i < quantity;i++){
cache.GetCachedFile(i.ToString(),"test",delegate(Stream s){
s.WriteByte(32); //Just one space
},defaultDate, 10);
}
}
int quantity;
CustomDiskCache cache = null;
DateTime defaultDate = new DateTime(2011, 1, 1);
[ThreadedRepeat(150)]
[Test(Order=1)]
public void TestAccess() {
CacheResult r =
cache.GetCachedFile(new Random().Next(0, quantity).ToString(), "test",
delegate(Stream s) { Assert.Fail("No files have been modified, this should not execute"); }, defaultDate, 100);
Assert.IsTrue(System.IO.File.Exists(r.PhysicalPath));
Assert.IsTrue(r.Result == CacheQueryResult.Hit);
}
volatile int seed = 0;
[Test (Order=2)]
[ThreadedRepeat(20)]
public void TestUpdate() {
//try to get a unique date time value
DateTime newTime = DateTime.UtcNow.AddDays(seed++);
CacheResult r =
cache.GetCachedFile(new Random().Next(0, quantity).ToString(), "test",
delegate(Stream s) {
s.WriteByte(32); //Just one space
}, newTime, 100);
Assert.AreEqual<DateTime>(newTime, System.IO.File.GetLastWriteTimeUtc(r.PhysicalPath));
Assert.IsTrue(r.Result == CacheQueryResult.Miss);
}
[Test(Order=3)]
public void TestClear() {
System.IO.Directory.Delete(cache.PhysicalCachePath, true);
}
}
}

Answer 1

I wont answer direct question about bug but I think following steps will help find the error and not get lost in popping message boxes
decrease numbers of totalfiles ,
subfolders to much lower values to
see if error persists in 2 or even 1
file counts
your tests code isn't
super easy, as it should be,
write tests for tests
so you know they are running
correct, maybe those random nexts
are the problem, maybe something
else, tests should be easy.
figure out what test breaks the
system, your code contains 3 tests,
and constructor, comment two other
tests and see which one produces
error
your threaded repeat 150
looks pretty sick, maybe try smaller
number like 2 or 3 if error is basic
even 2 threads might break, if you
run 150 threads I can understand
your trouble with message boxes
add logging and try catch - catch
that index exception and log your
class state carefully, after
inspecting it I think youll see
problem much more clearly.
Right now you cant figure out the problem I think, you got too many variables , not to mention you didnt provide code for your Cache class which might contain some simple error that is causing it, before MBunit features even begin to show up.