def test_make_imbalance_single_class():
 y_ = np.zeros((X.shape[0],))
 ratio = 0.5
 assert_raises(ValueError, make_imbalance, X, y_, ratio)

def test_make_imbalance_single_class ( ) : y_ = np . zeros ( ( X . shape [ 0 ] , ) ) ratio = 0.5 assert_raises ( ValueError , make_imbalance , X , y_ , ratio )
test either if an error when there is a single class .