diff --git a/libs/remix-simulator/package.json b/libs/remix-simulator/package.json
index 098e5cfa81..62630ecadb 100644
--- a/libs/remix-simulator/package.json
+++ b/libs/remix-simulator/package.json
@@ -43,7 +43,7 @@
     "mocha": "^5.2.0"
   },
   "scripts": {
-    "test": "./../../node_modules/.bin/mocha --require tsconfig-paths/register test/"
+    "test": "./../../node_modules/.bin/ts-node --require tsconfig-paths/register ./../../node_modules/.bin/mocha test/*.ts"
   },
   "publishConfig": {
     "access": "public"
diff --git a/libs/remix-simulator/src/genesis.ts b/libs/remix-simulator/src/genesis.ts
index 84b97526ff..efd8e0f65d 100644
--- a/libs/remix-simulator/src/genesis.ts
+++ b/libs/remix-simulator/src/genesis.ts
@@ -1,7 +1,7 @@
 import EthJSBlock from 'ethereumjs-block'
 import { BN } from 'ethereumjs-util'
 
-function generateBlock (executionContext) {
+export function generateBlock (executionContext) {
   const block = new EthJSBlock({
     header: {
       timestamp: (new Date().getTime() / 1000 | 0),
@@ -19,4 +19,3 @@ function generateBlock (executionContext) {
   })
 }
 
-module.exports = generateBlock
diff --git a/libs/remix-simulator/src/index.ts b/libs/remix-simulator/src/index.ts
index 042022eef5..d09d8216a8 100644
--- a/libs/remix-simulator/src/index.ts
+++ b/libs/remix-simulator/src/index.ts
@@ -1,3 +1,3 @@
 import { Provider } from './provider'
 
-export { Provider }
+export default { Provider }
diff --git a/libs/remix-simulator/src/provider.ts b/libs/remix-simulator/src/provider.ts
index c735a66674..d125516e2e 100644
--- a/libs/remix-simulator/src/provider.ts
+++ b/libs/remix-simulator/src/provider.ts
@@ -9,11 +9,10 @@ import merge from 'merge'
 import { Accounts } from './methods/accounts'
 import { Filters } from './methods/filters'
 import { Misc } from './methods/misc'
-import { Net } from './methods/net.js'
-import { Transactions } from './methods/transactions.js'
-import { Debug } from './methods/debug.js'
-
-const generateBlock = require('./genesis.js')
+import { Net } from './methods/net'
+import { Transactions } from './methods/transactions'
+import { Debug } from './methods/debug'
+import { generateBlock } from './genesis'
 
 export class Provider {
   options
diff --git a/libs/remix-simulator/test/accounts.ts b/libs/remix-simulator/test/accounts.ts
index fbe0e6e1eb..28c4dffbba 100644
--- a/libs/remix-simulator/test/accounts.ts
+++ b/libs/remix-simulator/test/accounts.ts
@@ -1,12 +1,12 @@
 /* global describe, before, it */
-const Web3 = require('web3')
-const RemixSim = require('../index.js')
+import Web3 from 'web3'
+import RemixSim from '../src/index'
 const web3 = new Web3()
-const assert = require('assert')
+import * as assert from 'assert'
 
 describe('Accounts', () => {
   before(function () {
-    const provider = new RemixSim.Provider()
+    const provider: any = new RemixSim.Provider()
     web3.setProvider(provider)
   })
 
diff --git a/libs/remix-simulator/test/blocks.ts b/libs/remix-simulator/test/blocks.ts
index fb048764de..300774c79a 100644
--- a/libs/remix-simulator/test/blocks.ts
+++ b/libs/remix-simulator/test/blocks.ts
@@ -1,12 +1,12 @@
 /* global describe, before, it */
-const Web3 = require('web3')
-const RemixSim = require('../index.js')
+import Web3 from 'web3'
+import RemixSim from '../src/index'
 const web3 = new Web3()
-const assert = require('assert')
+import * as assert from 'assert'
 
 describe('blocks', () => {
   before(() => {
-    const provider = new RemixSim.Provider({
+    const provider: any = new RemixSim.Provider({
       coinbase: '0x0000000000000000000000000000000000000001'
     })
     web3.setProvider(provider)
@@ -21,7 +21,7 @@ describe('blocks', () => {
         extraData: '0x0',
         gasLimit: 8000000,
         gasUsed: 0,
-        hash: block.hash.toString('hex'),
+        hash: block.hash.toString(),
         logsBloom: '0xe670ec64341771606e55d6b4ca35a1a6b75ee3d5145a99d05921026d1527331',
         miner: '0x0000000000000000000000000000000000000001',
         nonce: '0x0000000000000000',
@@ -92,7 +92,7 @@ describe('blocks', () => {
     it('should get block given its hash', async () => {
       const correctBlock = await web3.eth.getBlock(0)
       const numberTransactions = await (new Promise((resolve, reject) => {
-        web3._requestManager.send({method: 'eth_getUncleCountByBlockHash', params: [correctBlock.hash]}, (err, numberTransactions) => {
+        web3['_requestManager'].send({method: 'eth_getUncleCountByBlockHash', params: [correctBlock.hash]}, (err, numberTransactions) => {
           if (err) return reject(err)
           resolve(numberTransactions)
         })
@@ -105,7 +105,7 @@ describe('blocks', () => {
     it('should get block given its number', async () => {
       const correctBlock = await web3.eth.getBlock(0)
       const numberTransactions = await (new Promise((resolve, reject) => {
-        web3._requestManager.send({method: 'eth_getUncleCountByBlockHash', params: [0]}, (err, numberTransactions) => {
+        web3['_requestManager'].send({method: 'eth_getUncleCountByBlockHash', params: [0]}, (err, numberTransactions) => {
           if (err) return reject(err)
           resolve(numberTransactions)
         })
@@ -116,7 +116,7 @@ describe('blocks', () => {
 
   describe('eth_getStorageAt', () => {
     it('should get storage at position at given address', async () => {
-      const abi = [
+      const abi: any = [
         {
           'constant': false,
           'inputs': [
@@ -203,7 +203,7 @@ describe('blocks', () => {
       const contract = new web3.eth.Contract(abi)
       const accounts = await web3.eth.getAccounts()
 
-      const contractInstance = await contract.deploy({ data: code, arguments: [100] }).send({ from: accounts[0], gas: 400000 })
+      const contractInstance: any = await contract.deploy({ data: code, arguments: [100] }).send({ from: accounts[0], gas: 400000 })
       contractInstance.currentProvider = web3.eth.currentProvider
       contractInstance.givenProvider = web3.eth.currentProvider
 
@@ -223,7 +223,7 @@ describe('blocks', () => {
 
   describe('eth_call', () => {
     it('should get a value', async () => {
-      const abi = [
+      const abi: any = [
         {
           'constant': false,
           'inputs': [
@@ -310,7 +310,7 @@ describe('blocks', () => {
       const contract = new web3.eth.Contract(abi)
       const accounts = await web3.eth.getAccounts()
 
-      const contractInstance = await contract.deploy({ data: code, arguments: [100] }).send({ from: accounts[0], gas: 400000 })
+      const contractInstance: any = await contract.deploy({ data: code, arguments: [100] }).send({ from: accounts[0], gas: 400000 })
       contractInstance.currentProvider = web3.eth.currentProvider
       contractInstance.givenProvider = web3.eth.currentProvider
 
diff --git a/libs/remix-simulator/test/misc.ts b/libs/remix-simulator/test/misc.ts
index 134eb90461..8ccefbc27e 100644
--- a/libs/remix-simulator/test/misc.ts
+++ b/libs/remix-simulator/test/misc.ts
@@ -1,18 +1,18 @@
 /* global describe, before, it */
-const Web3 = require('web3')
-const RemixSim = require('../index.js')
+import Web3 from 'web3'
+import RemixSim from '../src/index'
 const web3 = new Web3()
-const assert = require('assert')
+import * as assert from 'assert'
 
 describe('Misc', () => {
   before(() => {
-    const provider = new RemixSim.Provider()
+    const provider: any = new RemixSim.Provider()
     web3.setProvider(provider)
   })
 
   describe('web3_clientVersion', () => {
     it('should get correct remix simulator version', async (done) => {
-      web3._requestManager.send({ method: 'web3_clientVersion', params: [] }, (err, version) => {
+      web3['_requestManager'].send({ method: 'web3_clientVersion', params: [] }, (err, version) => {
         if (err) {
           throw new Error(err)
         }
@@ -25,7 +25,7 @@ describe('Misc', () => {
 
   describe('eth_protocolVersion', () => {
     it('should get protocol version', async () => {
-      web3._requestManager.send({ method: 'eth_protocolVersion', params: [] }, (err, result) => {
+      web3['_requestManager'].send({ method: 'eth_protocolVersion', params: [] }, (err, result) => {
         if (err) {
           throw new Error(err)
         }
@@ -57,7 +57,7 @@ describe('Misc', () => {
 
   describe('web3_sha3', () => {
     it('should get result of a sha3', async () => {
-      web3._requestManager.send({ method: 'web3_sha3', params: ['0x68656c6c6f20776f726c64'] }, (err, result) => {
+      web3['_requestManager'].send({ method: 'web3_sha3', params: ['0x68656c6c6f20776f726c64'] }, (err, result) => {
         if (err) {
           throw new Error(err)
         }
@@ -68,7 +68,7 @@ describe('Misc', () => {
 
   describe('eth_getCompilers', () => {
     it('should get list of compilers', async () => {
-      web3._requestManager.send({ method: 'eth_getCompilers', params: [] }, (err, result) => {
+      web3['_requestManager'].send({ method: 'eth_getCompilers', params: [] }, (err, result) => {
         if (err) {
           throw new Error(err)
         }
@@ -79,7 +79,7 @@ describe('Misc', () => {
 
   describe('eth_compileSolidity', () => {
     it('get unsupported result when requesting solidity compiler', async () => {
-      web3._requestManager.send({ method: 'eth_compileSolidity', params: [] }, (err, result) => {
+      web3['_requestManager'].send({ method: 'eth_compileSolidity', params: [] }, (err, result) => {
         if (err) {
           throw new Error(err)
         }
@@ -90,7 +90,7 @@ describe('Misc', () => {
 
   describe('eth_compileLLL', () => {
     it('get unsupported result when requesting LLL compiler', async () => {
-      web3._requestManager.send({ method: 'eth_compileLLL', params: [] }, (err, result) => {
+      web3['_requestManager'].send({ method: 'eth_compileLLL', params: [] }, (err, result) => {
         if (err) {
           throw new Error(err)
         }
@@ -101,7 +101,7 @@ describe('Misc', () => {
 
   describe('eth_compileSerpent', () => {
     it('get unsupported result when requesting serpent compiler', async () => {
-      web3._requestManager.send({ method: 'eth_compileSerpent', params: [] }, (err, result) => {
+      web3['_requestManager'].send({ method: 'eth_compileSerpent', params: [] }, (err, result) => {
         if (err) {
           throw new Error(err)
         }
diff --git a/libs/remix-simulator/tsconfig.json b/libs/remix-simulator/tsconfig.json
index 4f27566be2..f19ef7e5a8 100644
--- a/libs/remix-simulator/tsconfig.json
+++ b/libs/remix-simulator/tsconfig.json
@@ -1,7 +1,8 @@
 {
     "extends": "../../tsconfig.json",
     "compilerOptions": {
-      "types": ["node"]
+      "types": ["node", "mocha"],
+      "esModuleInterop": true
     },
     "include": ["**/*.ts"]
   }
\ No newline at end of file
diff --git a/libs/remix-simulator/tsconfig.lib.json b/libs/remix-simulator/tsconfig.lib.json
index f8c817af2a..dcbbfc63c2 100644
--- a/libs/remix-simulator/tsconfig.lib.json
+++ b/libs/remix-simulator/tsconfig.lib.json
@@ -5,7 +5,7 @@
     "outDir": "../../dist/out-tsc",
     "declaration": true,
     "rootDir": "./src",
-    "types": ["node"]
+    "types": ["node", "mocha"]
   },
   "exclude": [
     "**/*.spec.ts",