Added pre-push hook to run unit tests on changed packages

fixes https://github.com/TryGhost/Toolbox/issues/532

- we should protect against failures entering `main` which could be
  avoided by running a quick unit test beforehand
- this reintroduces Lerna as it supports parallelisation and `--since`,
  to run linting and unit tests on packages that have changed since
  upstream

.github/hooks/pre-push

@@ -0,0 +1,10 @@
+#!/bin/bash
+
+[ -n "$CI" ] && exit 0
+
+GIT_BRANCH=$(git rev-parse --abbrev-ref HEAD)
+if [ "$GIT_BRANCH" = "main" ]; then
+    printf "ℹ️ Pushing to \033[0;42m$GIT_BRANCH\033[0m branch requires some checks in advance\n"
+
+    yarn lerna run --include-dependents --since ${GHOST_UPSTREAM:-origin}/$GIT_BRANCH test:unit
+fi

.github/workflows/test.yml

@@ -157,7 +157,7 @@ jobs:
           cache: yarn
 
       - run: yarn
-      - run: yarn workspaces run test:unit
+      - run: yarn test:unit
 
       - uses: actions/upload-artifact@v3
         if: startsWith(matrix.node, '16')

package.json

@@ -26,9 +26,10 @@
     "dev": "node .github/dev.js",
     "fix": "yarn cache clean && rm -rf node_modules && yarn",
     "knex-migrator": "yarn workspace ghost run knex-migrator",
-    "lint": "yarn workspaces run lint",
     "setup": "yarn && yarn workspace ghost run setup && git submodule update --init",
-    "test": "yarn workspaces run test",
+    "lint": "lerna run lint",
+    "test": "lerna run test",
+    "test:unit": "lerna run test:unit",
     "main": "yarn main:monorepo && yarn main:submodules",
     "main:monorepo": "git checkout main && git pull ${GHOST_UPSTREAM:-origin} main && yarn",
     "main:submodules": "git submodule sync && git submodule update && git submodule foreach \"git checkout main && git pull ${GHOST_UPSTREAM:-origin} main && yarn\"",
@@ -114,10 +115,16 @@
   "lint-staged": {
     "*.js": "eslint"
   },
+  "lerna": {
+    "version": "0.0.0",
+    "npmClient": "yarn",
+    "useWorkspaces": true
+  },
   "devDependencies": {
     "concurrently": "7.6.0",
     "eslint-plugin-ghost": "2.16.0",
     "husky": "8.0.3",
+    "lerna": "6.5.1",
     "lint-staged": "13.1.2"
   }
 }