public function testApiReduce_AllowsSparseInputValues_WithoutInitialValue()
{
$test = $this->getTest();
$mock = $test->createCallableMock();
$mock->expects($test->once())->method('__invoke')->with($test->identicalTo(3));
Promise::reduce([null, null, 1, null, 1, 1], $this->plus())->then($mock);
}