assert_raises_ctx.py

class assert_raises(object):

    def __init__(self, exc_type):
        self.exc_type = exc_type

    def __enter__(self):
        pass

    def __exit__(self, exc_type, exc_value, traceback):
        assert self.exc_type == exc_type, "Expected exception not raised"
        return True
        
# Usage
with assert_raises(Exception):
    raise Exception("Error")