CBSE Blockchain System Testing 3

Question 1

Which consensus-layer test verifies that a Byzantine node cannot force honest nodes to accept an invalid block?

Accepted Answer

Byzantine fault tolerance (BFT) test

Answer

Sybil resistance test

Answer

Throughput benchmark

Answer

Peer discovery test

Question 2

What is the primary goal of 'state explosion testing' in blockchain smart contract analysis?

Accepted Answer

Identifying all reachable contract states to uncover hidden execution paths

Answer

Measuring transaction throughput under high load

Answer

Testing that contract storage is wiped after self-destruct

Answer

Verifying EVM opcode gas costs

Question 3

During a blockchain node stress test, which metric best indicates the onset of a memory exhaustion denial-of-service condition?

Accepted Answer

Mempool size growing unbounded while node RAM utilization spikes

Answer

Block propagation latency

Answer

Peer count dropping below minimum

Answer

Hash rate fluctuation

Question 4

A smart contract allows the owner to withdraw all Ether with a single function call with no time-lock. Which test case best captures the associated risk?

Accepted Answer

Test that the owner can drain all funds instantly, simulating a rug-pull scenario

Answer

Call the withdraw function as a non-owner and verify it reverts

Answer

Test that the contract balance matches expected deposits

Answer

Verify that the function emits a Transfer event

Question 5

In blockchain interoperability testing, what does a 'cross-chain replay attack' test verify?

Accepted Answer

That signed transactions on one chain cannot be rebroadcast and executed on a different chain

Answer

That bridge contracts correctly validate Merkle proofs

Answer

That relayer nodes forward messages within acceptable latency

Answer

That chain IDs are correctly embedded in block headers

Question 6

Which testing approach is most appropriate for validating that a permissioned blockchain's access control policies are correctly enforced at the network layer?

Accepted Answer

Network-level penetration testing with unauthorized node identities

Answer

Unit testing of smart contract modifiers

Answer

Gas profiling of transactions

Answer

Merkle root verification

Question 7

What does 'differential testing' between two Ethereum client implementations (e.g., Geth and Nethermind) primarily detect?

Accepted Answer

Consensus bugs where clients disagree on the canonical chain

Answer

Performance regressions in a single client

Answer

Memory leaks in JSON-RPC handlers

Answer

Differences in default gas price settings