1  //SPDX-License-Identifier: MIT
  2  pragma solidity >= 0.4.15 < 0.9.0;
  3  
  4  library AssertBalance {
  5  
  6      /*
  7          Event: TestEvent
  8  
  9          Fired when an assertion is made.
 10  
 11          Params:
 12              result (bool) - Whether or not the assertion holds.
 13              message (string) - A message to display if the assertion does not hold.
 14      */
 15      event TestEvent(bool indexed result, string message);
 16  
 17      // ************************************** balances **************************************
 18  
 19      /*
 20          Function: balanceEqual
 21  
 22          Assert that the balance of an account 'A' is equal to a given number 'b'.
 23  
 24          : A.balance = b
 25  
 26          Params:
 27              A (address) - The first address.
 28              b (uint) - The balance.
 29              message (string) - A message that is sent if the assertion fails.
 30  
 31          Returns:
 32              result (bool) - The result.
 33      */
 34      function balanceEqual(address a, uint b, string memory message) public returns (bool result) {
 35          result = (a.balance == b);
 36          _report(result, message);
 37      }
 38  
 39      /*
 40          Function: balanceNotEqual
 41  
 42          Assert that the balance of an account 'A' is not equal to a given number 'b'.
 43  
 44          : A.balance != b
 45  
 46          Params:
 47              A (address) - The first address.
 48              b (uint) - The balance.
 49              message (string) - A message that is sent if the assertion fails.
 50  
 51          Returns:
 52              result (bool) - The result.
 53      */
 54      function balanceNotEqual(address a, uint b, string memory message) public returns (bool result) {
 55          result = (a.balance != b);
 56          _report(result, message);
 57      }
 58  
 59      /*
 60          Function: balanceIsZero
 61  
 62          Assert that the balance of an account 'A' is zero.
 63  
 64          : A.balance == 0
 65  
 66          Params:
 67              A (address) - The first address.
 68              message (string) - A message that is sent if the assertion fails.
 69  
 70          Returns:
 71              result (bool) - The result.
 72      */
 73      function balanceIsZero(address a, string memory message) public returns (bool result) {
 74          result = (a.balance == 0);
 75          _report(result, message);
 76      }
 77  
 78      /*
 79          Function: balanceIsNotZero
 80  
 81          Assert that the balance of an account 'A' is not zero.
 82  
 83          : A.balance != 0
 84  
 85          Params:
 86              A (address) - The first address.
 87              message (string) - A message that is sent if the assertion fails.
 88  
 89          Returns:
 90              result (bool) - The result.
 91      */
 92      function balanceIsNotZero(address a, string memory message) public returns (bool result) {
 93          result = (a.balance != 0);
 94          _report(result, message);
 95      }
 96  
 97      /******************************** internal ********************************/
 98  
 99          /*
100              Function: _report
101  
102              Internal function for triggering <TestEvent>.
103  
104              Params:
105                  result (bool) - The test result (true or false).
106                  message (string) - The message that is sent if the assertion fails.
107          */
108      function _report(bool result, string memory message) internal {
109          if(result)
110              emit TestEvent(true, "");
111          else
112              emit TestEvent(false, message);
113      }
114  
115  }