* Revert "Revert "Move mockito to 3.0.0-alpha. (#15949)" (#15979)"

This reverts commit e59651f9.

* More thenReturn to thenAnswer when mocking Futures

* Revert "More thenReturn to thenAnswer when mocking Futures"

This reverts commit 194d2cf41754ad171efd6bb5898cf73bce5a75ab as we are reverting engine roll.

* Revert "Revert "More thenReturn to thenAnswer when mocking Futures""

This reverts commit 52c9e96b304b220f66d78a252fccea0c8e0ef24c.

* Add dependency override

* Fix issue