public void TestProofOfWork()
{
// This params accepts any difficulty target.
var @params = NetworkParameters.UnitTests();
var block = new Block(@params, _blockBytes);
block.Nonce = 12346;
try
{
block.Verify();
Assert.Fail();
}
catch (VerificationException)
{
// Expected.
}
// Blocks contain their own difficulty target. The BlockChain verification mechanism is what stops real blocks
// from containing artificially weak difficulties.
block.TargetDifficulty = Block.EasiestDifficultyTarget;
// Now it should pass.
block.Verify();
// Break the nonce again at the lower difficulty level so we can try solving for it.
block.Nonce = 1;
try
{
block.Verify();
Assert.Fail();
}
catch (VerificationException)
{
// Expected to fail as the nonce is no longer correct.
}
// Should find an acceptable nonce.
block.Solve();
block.Verify();
Assert.AreEqual(block.Nonce, 2U);
}
/// <summary>
/// Returns a solved block that builds on top of this one. This exists for unit tests.
/// </summary>
internal Block CreateNextBlock(Address toAddress, uint time)
{
var block = new Block(NetworkParameters) {TargetDifficulty = _targetDifficulty};
block.AddCoinbaseTransaction(EmptyBytes);
// Add a transaction paying 50 coins to the "to" address.
var transaction = new Transaction(NetworkParameters);
transaction.AddOutput(new TransactionOutput(NetworkParameters, transaction, Utils.ToNanoCoins(50, 0),
toAddress));
// The input does not really need to be a valid signature, as long as it has the right general form.
var input = new TransactionInput(NetworkParameters, transaction,
Script.CreateInputScript(EmptyBytes, EmptyBytes));
// Importantly the outpoint hash cannot be zero as that's how we detect a coinbase transaction in isolation
// but it must be unique to avoid 'different' transactions looking the same.
var counter = new byte[32];
counter[0] = (byte) _transactionCounter++;
input.Outpoint.Hash = new Sha256Hash(counter);
transaction.AddInput(input);
block.AddTransaction(transaction);
block.PreviousBlockHash = Hash;
block.TimeSeconds = time;
block.Solve();
block.VerifyHeader();
return block;
}