Port coverage script with both hardhat and forge coverage

Author: ernestognw

package.json

@@ -13,7 +13,7 @@
     "compile": "hardhat compile",
     "lint": "prettier --log-level warn --ignore-path .gitignore '{contracts,test}/**/*.sol' --check",
     "lint:fix": "prettier --log-level warn --ignore-path .gitignore '{contracts,test}/**/*.sol' --write",
-    "coverage": "hardhat coverage",
+    "coverage": "scripts/checks/coverage.sh",
     "test": "hardhat test"
   },
   "homepage": "https://openzeppelin.com/contracts/",

scripts/checks/coverage.sh

@@ -0,0 +1,18 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+export COVERAGE=true
+export FOUNDRY_FUZZ_RUNS=10
+
+# Hardhat coverage
+hardhat coverage
+
+if [ "${CI:-"false"}" == "true" ]; then
+  # Foundry coverage
+  forge coverage --report lcov
+  # Remove zero hits
+  sed -i '/,0/d' lcov.info
+fi
+
+# Reports are then uploaded to Codecov automatically by workflow, and merged.