Test Token Withdrawal

[mialbu]

Precondition: Deploy a simple NEP-17 token, register it in the bridge and allocate funds of the NEP-17 token to the bridge contract.

Successful

• Use withdrawToken() with the deployed NEP-17 token and to as an EOA (not a contract) -> check event TokenWithdrawal
• Use withdrawToken() with the deployed NEP-17 token and to a contract -> check event TokenClaimable
• Use withdrawToken() with withdrawals that exceed the bridge's balance -> check event TokenClaimable
• Check event GasWithdrawalRootUpdate for a successful withdrawal
• Check updated root and nonce after a successful withdrawal

Invalid Cases

• Fail to withdraw if token bridge is not registered
• Fail to withdraw if withdrawals list parameter has size 0
• Fail if first withdrawal in withdrawals list parameter has not the next nonce
• Fail if withdrawals in withdrawals list parameter have no subsequent nonces
• Fail if provided withdrawalRoot is not equal the computed new root
• Fail if verifyValidatorSignatures() returns false (e.g., not enough signatures)