This commit adds one more underlying implementation of MockPersistedState.
Previously only InMemoryPersistentState was used, not GatewayMetaState
is used rarely.
When adding GatewayMetaState support the main question was: do we want to
emulate exceptions as we do today in MockPersistedState before
delegating to GatewayMetaState or do we want these exceptions to
propagate from the lower level, i.e. file system exceptions?
On the one hand, lower level exception propagation is already tested in
GatewayMetaStateTests, so this won't improve the coverage.
On the other hand, the benefit of low-level exceptions is to see how all these
components work in conjunction. Finally, we abandoned the idea of low-level
exceptions because we don't have a way to deal with IOError today in
CoordinatorTests, but hacking GatewayMetaState not to throw
IOError seems unnatural.
So MockPersistedState rarely throws an exception before delegating to
GatewayMetaState, which is not supposed to throw the exception.
This commit required two changes:
Move GatewayMetaStateUT to upper-level from
GatewayMetaStatePersistedStateTests, because otherwise, it's not easy
to construct GatewayMetaState instance in CoordinatorTests.
Move addition of STATE_NOT_RECOVERED_BLOCK from GatewayMetaState
constructor to GatewayMetaState.applyClusterUpdaters, because
CoordinatorTests class assumes that there is no such block and most of
them fail.
42fd68ed38