def test_block_valid():
"""Test validation of a block"""
block = Block(0, 'Test Data', timestamp=0)
assert block.hash_satisfies_difficulty
assert block.is_valid
block.difficulty = 4
assert block.hash_satisfies_difficulty is False
assert block.is_valid is False
block.proof = 49
assert block.proof == 49
assert block.hash_satisfies_difficulty
assert block.is_valid
# Introduce a fake hash
block.hash = '0f59bbd5a22a6484cc206b7ee9d4bc1744bed9c5649ff332f88a0eec461f58c8'
assert block.hash == '0f59bbd5a22a6484cc206b7ee9d4bc1744bed9c5649ff332f88a0eec461f58c8'
assert block.hash_satisfies_difficulty
assert block.is_valid is False
def test_block_difficulty():
"""Test proof-of-work validation"""
block = Block(0, 'Test Data', timestamp=0)
assert block.hash_satisfies_difficulty
block.difficulty = 4
assert block.hash_satisfies_difficulty is False
block.proof = 49
assert block.proof == 49
assert block.hash_satisfies_difficulty
block.proof = 5
assert block.proof == 5
assert block.hash_satisfies_difficulty is False