I need to write a test which verifies that my code can handle an AccessViolationException (or any other WIN32 Corrupted State Exception - CSE), which occours in an unsafe context, typically by calling a 3rd party lib. This should all be done using C# on .net 4.0.
I found this related question How to handle AccessViolationException and this related article http://dotnetslackers.com/articles/net/All-about-Corrupted-State-Exceptions-in-NET4.aspx, which explains how to catch these CSE's and their background.
So i would like to provoke a WIN32 CSE in a test, to ensure correct handling in my application. Something like:
Some example class to test:
public class MyExceptionHandler
{
[HandleProcessCorruptedStateExceptions]
public void HandleCorruptedStateException()
{
try
{
//Force genuine unsafe AccessViolationException
//not just a throw new AccessViolationException
}
catch(Exception e)
{
//Log/cleanup/other
}
}
public void DoesNotHandleCorruptedStateException()
{
try
{
//Force genuine unsafe AccessViolationException
//not just a throw new AccessViolationException
}
catch (Exception e)
{
//Log/cleanup/other
}
}
}
A Test:
class MyTest
{
[Test]
public void ShouldVerifyThatAnAccessViolationExceptionIsHandledCorrectly()
{
var handler = new MyExceptionHandler();
Assert.DoesNotThrow(() => handler.HandleCorruptedStateException());
}
[Test]
public void ShouldVerifyThatAnAccessViolationExceptionIsNotHandledCorrectly()
{
var handler = new MyExceptionHandler();
Assert.Throws<AccessViolationException>(() => handler.DoesNotHandleCorruptedStateException());
}
}
Does anyone have a suggestion of how to achive this without to much work (ex. writting a unsafe lib which causes this exception).
Kind regards
UPDATED: To match my final solution, thanks to JaredPar.
public class MyExceptionHandler
{
[HandleProcessCorruptedStateExceptions]
public void HandleCorruptedStateException()
{
try
{
var ptr = new IntPtr(42);
Marshal.StructureToPtr(42, ptr, true);
}
catch(Exception e)
{
//Log/cleanup/other
}
}
public void DoesNotHandleCorruptedStateException()
{
try
{
var ptr = new IntPtr(42);
Marshal.StructureToPtr(42, ptr, true);
}
catch (Exception e)
{
//Log/cleanup/other
}
}
}
TIP: To verify this manually use a simple console app, from the commandline:
class Program
{
static void Main(string[] args)
{
var handler = new MyExceptionHandler();
if (args.Length > 1)
{
handler.HandleCorruptedStateException();
}
else
{
handler.DoesNotHandleCorruptedStateException();
}
}
}
Try the following
var ptr = new IntPtr(42);
Marshal.StructureToPtr(42, ptr, true);
This isn't guaranteed to throw an AccessViolationException
by the CLI spec but it will on every platform I'm aware of
private static unsafe void AccessViolation()
{
int* p = (int*)0xFF004324;
int q = *p;
}
Edited out the unsafe write. Reading from that address should still generate an AccessViolationException unless coincidentally that is within your address space.
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