public function testInputFunctionsAreNotCallableException()
{
$intervals = [[-100, -2, false, true], [-2, 2], [2, 100, true, false]];
$functions = [new Polynomial([-1, 0]), 2, new Polynomial([1, 0])];
$this->setExpectedException('MathPHP\\Exception\\BadDataException');
$piecewise = new Piecewise($intervals, $functions);
}