[Numpy-discussion] Running tests that are marked as KNOWNFAIL

Is there a way to execute tests even if they are marked as KNOWNFAIL? For example, the module scipy.sparse.linalg has a few tests that are marked as such on my architecture (OS-X 64 bit). Running scipy.sparse.linalg(extra_argv=["--no-knownfail"]) changes the test result to ERROR, but it looks the actual test is still not run. The reason I'm asking is that when I remove the @dec.knownfailureif decorator from these tests by hand, they actually pass on my machine. Thanks, Lutz