convert AllowanceCrowdsale to initializers

contracts/crowdsale/emission/AllowanceCrowdsale.sol

 pragma solidity ^0.4.24;
 
+import "../../Initializable.sol";
 import "../Crowdsale.sol";
 import "../../token/ERC20/IERC20.sol";
 import "../../token/ERC20/SafeERC20.sol";
@@ -10,17 +11,20 @@ import "../../math/SafeMath.sol";
  * @title AllowanceCrowdsale
  * @dev Extension of Crowdsale where tokens are held by a wallet, which approves an allowance to the crowdsale.
  */
-contract AllowanceCrowdsale is Crowdsale {
+contract AllowanceCrowdsale is Initializable, Crowdsale {
   using SafeMath for uint256;
   using SafeERC20 for IERC20;
 
   address private _tokenWallet;
 
+  constructor(address tokenWallet) public {
+  }
+
   /**
    * @dev Constructor, takes token wallet address.
    * @param tokenWallet Address holding the tokens, which has approved allowance to the crowdsale
    */
-  constructor(address tokenWallet) public {
+  function initialize(address tokenWallet) public initializer {
     require(tokenWallet != address(0));
     _tokenWallet = tokenWallet;
   }

contracts/mocks/AllowanceCrowdsaleImpl.sol

 pragma solidity ^0.4.24;
 
+import "../Initializable.sol";
 import "../token/ERC20/IERC20.sol";
 import "../crowdsale/emission/AllowanceCrowdsale.sol";
 
 
-contract AllowanceCrowdsaleImpl is AllowanceCrowdsale {
+contract AllowanceCrowdsaleImpl is Initializable, Crowdsale, AllowanceCrowdsale {
 
   constructor (
     uint256 rate,
@@ -16,6 +17,8 @@ contract AllowanceCrowdsaleImpl is AllowanceCrowdsale {
     Crowdsale(rate, wallet, token)
     AllowanceCrowdsale(tokenWallet)
   {
+    Crowdsale.initialize(rate, wallet, token);
+    AllowanceCrowdsale.initialize(tokenWallet);
   }
 
 }

test/crowdsale/AllowanceCrowdsale.test.js

@@ -9,7 +9,7 @@ const should = require('chai')
   .should();
 
 const AllowanceCrowdsale = artifacts.require('AllowanceCrowdsaleImpl');
-const SimpleToken = artifacts.require('SimpleToken');
+const SimpleToken = artifacts.require('SimpleTokenMock');
 
 contract('AllowanceCrowdsale', function ([_, investor, wallet, purchaser, tokenWallet]) {
   const rate = new BigNumber(1);