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2) Examine the current tests (i.e. org.apache.kafka.streams.TopologyTest ), remove complicate and refactor the testing code logics and refactor with the new MockStateStores.

Rejected Alternatives

1) Rebuilding a MockStateStores vs extending an InMemoryStore

• If we are rebuilding the functionality of a store from scratch in memory, it will basically act like an InMemoryStore.

2) Track all calls in a total order.

• Now I haven't got a feature request to track calls within a total order, so now we track the order separately. If there is a need, we can definitely adjust it.

3）Using the MockStateStoreFactory as a main entry point to access stores. (Keeping the state of all StoreBuilder)

...

1. Using the current EasyMock implementation. There is no strong argument against the current EasyMock implementation, it is easy to use and lightweight. The main argument for this KIP is to write better tests with a in-house mock state store support.