tests: Improve coverage for StateTransitionerFactory (#365)

* tests: Improve coverage for StateTransitionerFactory

* fix failing test because of missing contract
Co-authored-by: Maurelian <maurelian@protonmail.ch>

packages/contracts/contracts/optimistic-ethereum/OVM/verification/OVM_StateTransitionerFactory.sol

@@ -23,15 +23,20 @@ import { OVM_StateTransitioner } from "./OVM_StateTransitioner.sol";
  */
 contract OVM_StateTransitionerFactory is iOVM_StateTransitionerFactory, Lib_AddressResolver {
 
+    /***************
+     * Constructor *
+     ***************/
+
     constructor(
         address _libAddressManager
     )
         Lib_AddressResolver(_libAddressManager)
     {}
 
-    /***************************************
-     * Public Functions: Contract Creation *
-     ***************************************/
+
+    /********************
+     * Public Functions *
+     ********************/
 
     /**
      * Creates a new OVM_StateTransitioner
@@ -39,7 +44,7 @@ contract OVM_StateTransitionerFactory is iOVM_StateTransitionerFactory, Lib_Addr
      * @param _stateTransitionIndex Index of the state transition being verified.
      * @param _preStateRoot State root before the transition was executed.
      * @param _transactionHash Hash of the executed transaction.
-     * @return _ovmStateTransitioner New OVM_StateTransitioner instance.
+     * @return New OVM_StateTransitioner instance.
      */
     function create(
         address _libAddressManager,
@@ -50,13 +55,14 @@ contract OVM_StateTransitionerFactory is iOVM_StateTransitionerFactory, Lib_Addr
         override
         public
         returns (
-            iOVM_StateTransitioner _ovmStateTransitioner
+            iOVM_StateTransitioner
         )
     {
         require(
             msg.sender == resolve("OVM_FraudVerifier"),
             "Create can only be done by the OVM_FraudVerifier."
         );
+
         return new OVM_StateTransitioner(
             _libAddressManager,
             _stateTransitionIndex,

packages/contracts/test/contracts/OVM/verification/OVM_StateTransitionerFactory.spec.ts

@@ -2,7 +2,8 @@ import { expect } from '../../../setup'
 
 /* External Imports */
 import { ethers } from 'hardhat'
-import { ContractFactory, Contract, constants } from 'ethers'
+import { ContractFactory, Contract, constants, Signer } from 'ethers'
+import { MockContract, smockit } from '@eth-optimism/smock'
 
 /* Internal Imports */
 import {
@@ -14,6 +15,11 @@ import {
 const DUMMY_HASH = hashTransaction(DUMMY_OVM_TRANSACTIONS[0])
 
 describe('OVM_StateTransitionerFactory', () => {
+  let signer1: Signer
+  before(async () => {
+    ;[signer1] = await ethers.getSigners()
+  })
+
   let AddressManager: Contract
   before(async () => {
     AddressManager = await makeAddressManager()
@@ -27,15 +33,26 @@ describe('OVM_StateTransitionerFactory', () => {
   })
 
   let OVM_StateTransitionerFactory: Contract
+  let Mock__OVM_StateManagerFactory: MockContract
   beforeEach(async () => {
     OVM_StateTransitionerFactory = await Factory__OVM_StateTransitionerFactory.deploy(
       AddressManager.address
     )
+
+    Mock__OVM_StateManagerFactory = await smockit('OVM_StateManagerFactory')
+    Mock__OVM_StateManagerFactory.smocked.create.will.return.with(
+      ethers.constants.AddressZero
+    )
+
+    await AddressManager.setAddress(
+      'OVM_StateManagerFactory',
+      Mock__OVM_StateManagerFactory.address
+    )
   })
 
   describe('create', () => {
     describe('when the sender is not the OVM_FraudVerifier', () => {
-      before(async () => {
+      beforeEach(async () => {
         await AddressManager.setAddress(
           'OVM_FraudVerifier',
           constants.AddressZero
@@ -55,5 +72,25 @@ describe('OVM_StateTransitionerFactory', () => {
         )
       })
     })
+
+    describe('when the sender is the OVM_FraudVerifier', () => {
+      beforeEach(async () => {
+        await AddressManager.setAddress(
+          'OVM_FraudVerifier',
+          await signer1.getAddress()
+        )
+      })
+
+      it('should not revert', async () => {
+        await expect(
+          OVM_StateTransitionerFactory.connect(signer1).create(
+            AddressManager.address,
+            ethers.constants.HashZero,
+            ethers.constants.HashZero,
+            DUMMY_HASH
+          )
+        ).to.not.be.reverted
+      })
+    })
   })
 })