feat: add GitHub workflow

Author: lukaszklis

.github/workflows/check.yaml

@@ -0,0 +1,51 @@
+name: Check
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  check:
+    if: ${{ !github.event.repository.is_template }}
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Setup pnpm
+        uses: pnpm/action-setup@v4
+        with:
+          version: 10
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: 24
+          cache: 'pnpm'
+
+      - name: Install dependencies
+        run: pnpm install --frozen-lockfile
+
+      - name: Run linter
+        run: pnpm lint
+
+      - name: Check formatting
+        run: pnpm format:check
+
+      - name: Get changed files
+        id: changed-files
+        run: |
+          if [ "${{ github.event_name }}" == "pull_request" ]; then
+            CHANGED=$(git diff --name-only origin/${{ github.base_ref }}...HEAD | tr '\n' ' ')
+          else
+            CHANGED=$(git diff --name-only ${{ github.event.before }} ${{ github.sha }} | tr '\n' ' ')
+          fi
+          echo "files=$CHANGED" >> $GITHUB_OUTPUT
+
+      - name: Validate test files follow template
+        run: bash scripts/validate-test-files.sh ${{ steps.changed-files.outputs.files }}

README.md

@@ -76,6 +76,28 @@ After generating a day, you can:
 - `pnpm format` - Format code with Prettier
 - `pnpm format:check` - Check code formatting
 
+## GitHub Actions
+
+This repository includes a GitHub Actions workflow (`.github/workflows/check.yaml`) that automatically runs on pull requests and pushes to the `main` branch. The workflow:
+
+- Runs the linter (`pnpm lint`)
+- Checks code formatting (`pnpm format:check`)
+- Validates that test files have not been changed to contain hardcoded answers
+
+### Enabling Required Status Checks
+
+To enforce that all checks pass before merging pull requests:
+
+1. Go to your repository **Settings**
+1. Navigate to **Rules** → **Rulesets**
+1. Click **New ruleset** → **New branch ruleset**
+1. Configure the ruleset name and target branches (e.g., `main`)
+1. Enable **Require status checks to pass**
+1. Click **Show additional settings**
+1. Under **Status checks that are required**, click **Add checks**
+1. Type `check` and select the **check** action
+1. Click **Save changes**
+
 ## Excluded Files
 
 - Input files (`input*.txt`)

package.json

@@ -1,7 +1,7 @@
 {
   "name": "advent-of-code",
   "description": "Advent of Code solutions",
-  "version": "1.1.0",
+  "version": "1.2.0",
   "type": "module",
   "scripts": {
     "generate-day": "tsx scripts/generate-day.ts",

scripts/validate-test-files.sh

@@ -0,0 +1,101 @@
+#!/bin/bash
+
+# This script validates that solution.test.ts files follow the expected template.
+# This ensures that test files don't contain hardcoded answers.
+#
+# Usage:
+#   bash scripts/validate-test-files.sh [files...]
+#
+# If no files are provided, validates all src/day*/solution.test.ts files.
+# If files are provided, only validates those that match solution.test.ts pattern.
+
+FAILED=0
+CHECKED=0
+TEMPLATE='import { readFile } from '\''node:fs/promises'\''
+import { dirname, join } from '\''node:path'\''
+import { fileURLToPath } from '\''node:url'\''
+import { describe, expect, it } from '\''vitest'\''
+import { part1, part2 } from '\''./solution'\''
+
+const __filename = fileURLToPath(import.meta.url)
+const __dirname = dirname(__filename)
+
+describe('\''Day DAY_NUMBER'\'', () => {
+  it('\''should solve part 1'\'', async () => {
+    const input = await readFile(join(__dirname, '\''input1.txt'\''), '\''utf-8'\'')
+    const expectation = await readFile(join(__dirname, '\''expectation1.txt'\''), '\''utf-8'\'')
+
+    expect(part1(input.trim())).toBe(expectation.trim())
+  })
+
+  it('\''should solve part 2'\'', async () => {
+    const input = await readFile(join(__dirname, '\''input2.txt'\''), '\''utf-8'\'')
+    const expectation = await readFile(join(__dirname, '\''expectation2.txt'\''), '\''utf-8'\'')
+
+    expect(part2(input.trim())).toBe(expectation.trim())
+  })
+})
+'
+
+validate_file() {
+  local file="$1"
+
+  # Skip if not a solution.test.ts file
+  if [[ ! "$file" =~ solution\.test\.ts$ ]]; then
+    return
+  fi
+
+  # Skip if file doesn't exist (e.g., deleted in the diff)
+  if [ ! -f "$file" ]; then
+    return
+  fi
+
+  CHECKED=$((CHECKED + 1))
+
+  # Extract day number from directory name (e.g., day01 -> 1, day12 -> 12)
+  DAY_NUM=$(echo "$file" | sed -E 's/.*day0*([0-9]+).*/\1/')
+
+  # Create expected content for this day
+  EXPECTED=$(echo "$TEMPLATE" | sed "s/DAY_NUMBER/$DAY_NUM/g")
+
+  # Get actual file content
+  ACTUAL=$(cat "$file")
+
+  if [ "$EXPECTED" != "$ACTUAL" ]; then
+    echo "❌ $file does not match the expected template"
+    echo "This check ensures test files don't contain hardcoded answers."
+    echo ""
+    echo "Expected content:"
+    echo "$EXPECTED"
+    echo ""
+    echo "Actual content:"
+    echo "$ACTUAL"
+    FAILED=1
+  else
+    echo "✅ $file matches template"
+  fi
+}
+
+# If arguments provided, validate only those files
+# Otherwise, validate all solution.test.ts files
+if [ $# -gt 0 ]; then
+  for file in "$@"; do
+    validate_file "$file"
+  done
+else
+  for file in src/day*/solution.test.ts; do
+    validate_file "$file"
+  done
+fi
+
+if [ $CHECKED -eq 0 ]; then
+  echo "No solution.test.ts files to validate"
+  exit 0
+fi
+
+if [ $FAILED -eq 1 ]; then
+  echo ""
+  echo "Some test files don't match the expected template."
+  echo "Please ensure test files only contain the standard template without modifications."
+  exit 1
+fi