Unit tests for the Blockstore

[AlexandraRoatis]

Type of change

• Bug fix.
• New feature.
• Enhancement.
• Unit test.
• Breaking change (a fix or feature that causes existing functionality to not work as expected).
• Requires documentation update.

[AionJayT]

I think this change will let AionBlockChainImpl.isValid() throw null exception. Please have a check.

[AlexandraRoatis]

I updated the null check in AionBlockchainImpl.isValid to exit if the parent block is null.

[AionJayT]

Cool.

[AionJayT]

Will let AionBlockChainImpl.createNewMiningBlockInternal() throw NPE

[AlexandraRoatis]

It would already throw an NPE because the blockFamily is accessed without a null check. The reason for the NPE differs but it will be thown in either case. If that happens I think we should allows the failure and fix the cause when we find one.

[AionJayT]

So We should just throw NPE if the input hash equal to null. instead of return values (or return null)

Same as the other method.

[AlexandraRoatis]

Ok. I made the update.