cniAddServerCalled = true
		if serverErr {
			res.WriteHeader(http.StatusInternalServerError)
			res.Write([]byte("server not happy"))
			return
		}
		res.WriteHeader(http.StatusOK)
		res.Write([]byte("server happy"))
	}))

	return testServer.URL, func() bool {
		testServer.Close()
		return cniAddServerCalled
	}
}