public function dataProviderForPowersOfTen() { return [[-1, []], [0, []], [1, [1]], [2, [1, 10]], [3, [1, 10, 100]], [10, [1, 10, 100, 1000, 10000, 100000, 1000000, 10000000, 100000000, 1000000000]]]; }