Add coverage testing script (#348)

* Add coverage config

* Add flags to skip gas tests when running coverage

* Check-in coverage output

* Revert "Check-in coverage output"


Too noisy to have coverage output stored here. I will look for an alternative solution.

This reverts commit fb631f2471903e9b8ab76c66e18f308d92930cae.

* Add test coverage artifacts to gitignore

* Add test coverage instructions to README

* Lint

packages/contracts/.gitignore

@@ -6,3 +6,7 @@ cache-ovm/
 yarn-error.log
 build/
 .DS_STORE
+
+# Coverage output
+coverage/
+coverage.json

packages/contracts/.solcover.js

+module.exports = {
+  skipFiles: [
+    './test-helpers',
+    './test-libraries',
+    './optimistic-ethereum/mockOVM'
+  ],
+  mocha: {
+    grep: "@skip-on-coverage",
+    invert: true
+  }
+};

packages/contracts/README.md

@@ -54,6 +54,16 @@ Run specific tests by giving a path to the file you want to run:
 yarn test ./test/path/to/my/test.spec.ts
 ```
 
+### Measuring test coverage:
+```shell
+yarn test-coverage
+```
+
+The output is most easily viewable by opening the html file in your browser:
+```shell
+open ./coverage/index.html
+```
+
 ### Compiling and Building
 Easiest way is to run the primary build script:
 ```shell

packages/contracts/hardhat.config.ts

 import { HardhatUserConfig } from 'hardhat/types'
+import 'solidity-coverage'
 
 import {
   DEFAULT_ACCOUNTS_HARDHAT,

packages/contracts/package.json

@@ -28,6 +28,7 @@
     "test": "yarn run test:contracts",
     "test:contracts": "hardhat test --show-stack-traces",
     "test:gas": "hardhat test \"test/contracts/OVM/execution/OVM_StateManager.gas-spec.ts\" --no-compile --show-stack-traces",
+    "test-coverage": "NODE_OPTIONS=--max_old_space_size=8192 hardhat coverage",
     "lint": "yarn run lint:typescript",
     "lint:typescript": "tslint --format stylish --project .",
     "lint:fix": "yarn run lint:fix:typescript",
@@ -46,7 +47,8 @@
     "@openzeppelin/contracts": "^3.3.0",
     "@typechain/hardhat": "^1.0.1",
     "ganache-core": "^2.13.2",
-    "glob": "^7.1.6"
+    "glob": "^7.1.6",
+    "solidity-coverage": "^0.7.16"
   },
   "devDependencies": {
     "@eth-optimism/plugins": "^1.0.0-alpha.2",

packages/contracts/test/contracts/OVM/chain/OVM_CanonicalTransactionChain.gas.spec.ts

@@ -129,7 +129,7 @@ describe('[GAS BENCHMARK] OVM_CanonicalTransactionChain', () => {
     )
   })
 
-  describe('appendSequencerBatch', () => {
+  describe('appendSequencerBatch [ @skip-on-coverage ]', () => {
     beforeEach(() => {
       OVM_CanonicalTransactionChain = OVM_CanonicalTransactionChain.connect(
         sequencer

packages/contracts/test/contracts/OVM/execution/OVM_ExecutionManager.gas-spec.ts

@@ -101,7 +101,7 @@ describe('OVM_ExecutionManager gas consumption', () => {
     ).connect(wallet)
   })
 
-  describe('Measure cost of a very simple contract', async () => {
+  describe('Measure cost of a very simple contract  [ @skip-on-coverage ]', async () => {
     it('Gas cost of run', async () => {
       const gasCost = await gasMeasurement.getGasCost(
         OVM_ExecutionManager,

packages/contracts/test/contracts/OVM/execution/OVM_StateManager.gas-spec.ts

@@ -21,7 +21,7 @@ const DUMMY_KEY = DUMMY_BYTES32[0]
 const DUMMY_VALUE_1 = DUMMY_BYTES32[1]
 const DUMMY_VALUE_2 = DUMMY_BYTES32[2]
 
-describe('OVM_StateManager gas consumption', () => {
+describe('OVM_StateManager gas consumption [ @skip-on-coverage ]', () => {
   let owner: Signer
   before(async () => {
     ;[owner] = await ethers.getSigners()