Nosetests not seeing test classes that unittest discover does

I have what I can only consider a very odd problem with the way nosetests identifies classes that are valid tests classes.

I'm initialising a test class as a generic type with specific inheritance from a base tests class by using:

def random_test_class(n):
    print "Generating %d random test cases..." % n
    def make_test(genre, ss, ps):
        return lambda self: self.compose(genre, ss, ps)
    return type('TestEverything', (TestBase,),
                { 'test_%d' % i: make_test(genre, ss, ps)
                  for (i, (genre, ss, ps)) in zip(xrange(n), generate_settings())
                })

and then initialising the class proper with

class TestEverything(random_test_class(100)):
    pass

Now, when I call my standard testing framework with python -m unittest discover, the testing is all very happy and it sees the TestEverything class as a test class defining 100 test methods (test_1, test_2, etc...). However, if I use nosetests ./ -m "test_*" it refuses to see TestEverything as a valid test class, and doesn't run any of its test methods.

How can I solve this? I really need the xunit output framework that nosetests provide, but I would very much like to avoid going through all the metaclass faff that is required to properly initialise a class with a specific test metaclass.