Added message string for require() (#1704)

* Error handling in ERC20 and ERC721

* Added message string for require.

* Fixed solhint errors.

* Updated PR as per issue #1709

* changes as per #1709 and openzeppelin forum.

* Changes in require statement

* Changes in require statement

* build pipeline fix

* Changes as per @nventuro's comment.

* Update revert reason strings.

* Fianal update of revert reason strings.

* WIP: Updating reason strings in test cases

* WIP: Added changes to ERC20 and ERC721

* Fixes linting errors in *.tes.js files

* Achieved 100% code coverage

* Updated the test cases with shouldFail.reverting.withMessage()

* Fix package-lock.

* address review comments

* fix linter issues

* fix remaining revert reasons

contracts/access/Roles.sol

@@ -13,8 +13,7 @@ library Roles {
      * @dev Give an account access to this role.
      */
     function add(Role storage role, address account) internal {
-        require(!has(role, account));
-
+        require(!has(role, account), "Roles: account already has role");
         role.bearer[account] = true;
     }
 
@@ -22,8 +21,7 @@ library Roles {
      * @dev Remove an account's access to this role.
      */
     function remove(Role storage role, address account) internal {
-        require(has(role, account));
-
+        require(has(role, account), "Roles: account does not have role");
         role.bearer[account] = false;
     }
 
@@ -32,7 +30,7 @@ library Roles {
      * @return bool
      */
     function has(Role storage role, address account) internal view returns (bool) {
-        require(account != address(0));
+        require(account != address(0), "Roles: account is the zero address");
         return role.bearer[account];
     }
 }

contracts/access/roles/CapperRole.sol

@@ -15,7 +15,7 @@ contract CapperRole {
     }
 
     modifier onlyCapper() {
-        require(isCapper(msg.sender));
+        require(isCapper(msg.sender), "CapperRole: caller does not have the Capper role");
         _;
     }
 

contracts/access/roles/MinterRole.sol

@@ -15,7 +15,7 @@ contract MinterRole {
     }
 
     modifier onlyMinter() {
-        require(isMinter(msg.sender));
+        require(isMinter(msg.sender), "MinterRole: caller does not have the Minter role");
         _;
     }
 

contracts/access/roles/PauserRole.sol

@@ -15,7 +15,7 @@ contract PauserRole {
     }
 
     modifier onlyPauser() {
-        require(isPauser(msg.sender));
+        require(isPauser(msg.sender), "PauserRole: caller does not have the Pauser role");
         _;
     }
 

contracts/access/roles/SignerRole.sol

@@ -15,7 +15,7 @@ contract SignerRole {
     }
 
     modifier onlySigner() {
-        require(isSigner(msg.sender));
+        require(isSigner(msg.sender), "SignerRole: caller does not have the Signer role");
         _;
     }
 

contracts/access/roles/WhitelistAdminRole.sol

@@ -19,7 +19,7 @@ contract WhitelistAdminRole {
     }
 
     modifier onlyWhitelistAdmin() {
-        require(isWhitelistAdmin(msg.sender));
+        require(isWhitelistAdmin(msg.sender), "WhitelistAdminRole: caller does not have the WhitelistAdmin role");
         _;
     }
 

contracts/access/roles/WhitelistedRole.sol

@@ -18,7 +18,7 @@ contract WhitelistedRole is WhitelistAdminRole {
     Roles.Role private _whitelisteds;
 
     modifier onlyWhitelisted() {
-        require(isWhitelisted(msg.sender));
+        require(isWhitelisted(msg.sender), "WhitelistedRole: caller does not have the Whitelisted role");
         _;
     }