Add validators amount limit (#239)

contracts/upgradeable_contracts/BaseBridgeValidators.sol

@@ -9,6 +9,7 @@ contract BaseBridgeValidators is EternalStorage, Ownable {
     using SafeMath for uint256;
 
     address public constant F_ADDR = 0xFFfFfFffFFfffFFfFFfFFFFFffFFFffffFfFFFfF;
+    uint256 internal constant MAX_VALIDATORS = 100;
 
     event ValidatorAdded (address indexed validator);
     event ValidatorRemoved (address indexed validator);

contracts/upgradeable_contracts/BridgeValidators.sol

@@ -18,6 +18,7 @@ contract BridgeValidators is BaseBridgeValidators {
         setOwner(_owner);
         require(_requiredSignatures != 0);
         require(_initialValidators.length >= _requiredSignatures);
+        require(_initialValidators.length <= MAX_VALIDATORS);
 
         for (uint256 i = 0; i < _initialValidators.length; i++) {
             require(_initialValidators[i] != address(0) && _initialValidators[i] != F_ADDR);

contracts/upgradeable_contracts/RewardableValidators.sol

@@ -19,6 +19,7 @@ contract RewardableValidators is BaseBridgeValidators {
         setOwner(_owner);
         require(_requiredSignatures != 0);
         require(_initialValidators.length >= _requiredSignatures);
+        require(_initialValidators.length <= MAX_VALIDATORS);
         require(_initialValidators.length == _initialRewards.length);
 
         for (uint256 i = 0; i < _initialValidators.length; i++) {

test/helpers/helpers.js

@@ -162,3 +162,13 @@ function isBN(object) {
 }
 
 module.exports.expectEventInLogs = expectEventInLogs
+
+function createAccounts(web3, amount) {
+  const array = []
+  for (let i = 0; i < amount; i++) {
+    array[i] = web3.eth.accounts.create().address
+  }
+  return array
+}
+
+module.exports.createAccounts = createAccounts

test/rewardable_validators_test.js

@@ -3,7 +3,7 @@ const EternalStorageProxy = artifacts.require('EternalStorageProxy.sol')
 
 const { expect } = require('chai')
 const { ERROR_MSG, ZERO_ADDRESS, F_ADDRESS, BN } = require('./setup')
-const { expectEventInLogs } = require('./helpers/helpers')
+const { expectEventInLogs, createAccounts } = require('./helpers/helpers')
 
 const ZERO = new BN(0)
 
@@ -60,6 +60,21 @@ contract('RewardableValidators', async accounts => {
       expect(minor).to.be.bignumber.gte(ZERO)
       expect(patch).to.be.bignumber.gte(ZERO)
     })
+    it('should fail if exceed amount of validators', async () => {
+      // Given
+      const validators = createAccounts(web3, 101)
+
+      // When
+      await bridgeValidators
+        .initialize(99, validators, validators, accounts[2], { from: accounts[2] })
+        .should.be.rejectedWith(ERROR_MSG)
+      await bridgeValidators.initialize(99, validators.slice(0, 100), validators.slice(0, 100), accounts[2], {
+        from: accounts[2]
+      }).should.be.fulfilled
+
+      // Then
+      expect(await bridgeValidators.validatorCount()).to.be.bignumber.equal('100')
+    })
   })
 
   describe('#addValidator', async () => {

test/validators_test.js

@@ -3,7 +3,7 @@ const EternalStorageProxy = artifacts.require('EternalStorageProxy.sol')
 
 const { expect } = require('chai')
 const { ERROR_MSG, ZERO_ADDRESS, F_ADDRESS, BN } = require('./setup')
-const { expectEventInLogs } = require('./helpers/helpers')
+const { expectEventInLogs, createAccounts } = require('./helpers/helpers')
 
 const ZERO = new BN(0)
 
@@ -48,6 +48,20 @@ contract('BridgeValidators', async accounts => {
       expect(minor).to.be.bignumber.gte(ZERO)
       expect(patch).to.be.bignumber.gte(ZERO)
     })
+    it('should fail if exceed amount of validators', async () => {
+      // Given
+      const validators = createAccounts(web3, 101)
+
+      // When
+      await bridgeValidators
+        .initialize(99, validators, accounts[2], { from: accounts[2] })
+        .should.be.rejectedWith(ERROR_MSG)
+      await bridgeValidators.initialize(99, validators.slice(0, 100), accounts[2], { from: accounts[2] }).should.be
+        .fulfilled
+
+      // Then
+      expect(await bridgeValidators.validatorCount()).to.be.bignumber.equal('100')
+    })
   })
 
   describe('#addValidator', async () => {