Got tests running

packages/contracts/buidler.config.ts

@@ -8,7 +8,7 @@ import {
 usePlugin('@nomiclabs/buidler-ethers')
 usePlugin('@nomiclabs/buidler-waffle')
 
-import '@eth-optimism/smock/src/buidler-plugins/compiler-storage-layout'
+import '@eth-optimism/smock/build/src/buidler-plugins/compiler-storage-layout'
 
 const config: BuidlerConfig = {
   networks: {

packages/contracts/package.json

@@ -18,7 +18,7 @@
     "clean": "rm -rf ./artifacts ./build ./cache"
   },
   "devDependencies": {
-    "@eth-optimism/smock": "^0.0.1",
+    "@eth-optimism/smock": "^0.0.2",
     "@nomiclabs/buidler": "^1.4.4",
     "@nomiclabs/buidler-ethers": "^2.0.0",
     "@nomiclabs/buidler-waffle": "^2.0.0",

packages/contracts/test/contracts/OVM/chain/OVM_StateCommitmentChain.spec.ts

@@ -11,6 +11,8 @@ import {
   setProxyTarget,
   NON_NULL_BYTES32,
   ZERO_ADDRESS,
+  toHexString32,
+  getEthTime,
 } from '../../../helpers'
 import { keccak256 } from 'ethers/lib/utils'
 
@@ -112,6 +114,7 @@ describe('OVM_StateCommitmentChain', () => {
         batch.length
       )
       await OVM_StateCommitmentChain.appendStateBatch(batch)
+      batchHeader.extraData = toHexString32(await getEthTime(ethers.provider))
     })
 
     describe('when the sender is not the OVM_FraudVerifier', () => {