multiple_contract_test

This illustrates how to use one contract with in another contract.

Files and Descriptions

contract/Add.sol

addValue add the passed value to state variable _currentValue

contract/Math.sol

Constructor receive the address of the Add class squareValue square the passed value and store in state variable _currentValue To square the value, Math contract use addValue function in Add contract

senderCheck function

• This take one parameter, which is the address of the function invoker (userAcc2)

• In the context of Math.senderCheck, sender is the one who invoked the contract function (refer TestAddSquare.js)

  • require (msg.sender == addr); // Sender is invoked user's address

• In the context of Add.senderCheck, sender is the Math contract who invoked the Add.sendChecker functon in Math.sol

  • require (msg.sender == conAddr); // Sender is Math contract address
  • require (msg.sender != accAddr); // Sender NOT the user who invoked the function

• In the context of Add.senderCheck, tx.origin is the one who invoked the contract function
  • require (tx.origin == accAddr); // tx.origin is the user who invoked the function

test/TestAddSquare.js

Set of unit tests to check the functionality

Setting up contracts

• Deploy contract Add to a testnet and obtain the contract address (add_address)
• Deploy contract Math to the same testnet with the add_address as a constructor parameter

Contract call another contract

• When you invoke Math.squareValue it internally calls Add.addValue