'Evaluate function definition.'

def test_FunctionDefinition(self):

    done = self.recvlineClient.expect('done')
    self._testwrite('def    foo(bar):\n DCTB print(bar)\n\nfoo(42)\ndone')
    def finished(ign):
        self._assertBuffer(['>>>    def    foo(bar):', '...                    print(bar)', '...    ', '>>>    foo(42)', '42', '>>>    done'])
    return done.addCallback(finished)
