Hello.
I work for a small billing software company, which has
adopted NUNIT a couple of years back, and now every developer here writes NUINT
tests during development cycle – this is a great product. Our software
base is a combination of managed C#/C++ code and unmanaged COM code, which we
still via COM Interop.
Recently I encountered a small issue, which prompted
me to change UNIT framework a little bit, and I wanted to know if you think it
would be useful to integrate this change into the official version of
framework.
The
issue comes up when I write negative tests and want to use ExpectedException
attribute. Sometimes it is not enough to know the type of the exception when
the test runs, but rather compare the instances of exception. A classic example
of this would be testing on COM interop code, where every exception thrown is
an instance of COMException class. So I always had to write additional code to
examine the HRESULT on the exception, something like this:
[ExpectedException(typeof(System.Runtime.InteropServices.COMException))]
public void
MyNegativeUseCase()
{
try
{
...
}
catch(COMException e)
{
long MY_EXPECTED_HRESULT
= 0xEEBF004EL;
Assertion.AssertEquals(_EXPECTED_HRESULT, (long)e.ErrorCode);
throw;
}
}
Recently I introduced another class called
ExpectedComException, and things became much easier:
[ExpectedComException(0xEEBF004EL)]
public void
TestAddInvalidConstraintToPO()
{
Utils.TestComException(0xEEBF004EL();
}
Basically, if a COMException with the error code different
from the one that I expect, test suite throws an error indicating this.
Although COMException is the only case where I needed this, I am pretty sure
that it could be useful to create exception instance level attributes even for
managed exceptions. Sometimes you may want to examine more than the type of exception
to validate that your test succeeded.
If you think that this change may be useful, I will make
things nice and neat and send the mods along with test cases.
Please let me know.
Thank you very much.
Boris Partensky
