Add pnpm integration test

test/integration/pnpm/app/package.json

@@ -0,0 +1,14 @@
+{
+  "name": "pnpm-app",
+  "version": "1.0.0",
+  "private": true,
+  "scripts": {
+    "dev": "next dev",
+    "build": "next build",
+    "start": "next start"
+  },
+  "dependencies": {
+    "react": "^16.7.0",
+    "react-dom": "^16.7.0"
+  }
+}

test/integration/pnpm/app/pages/index.js

@@ -0,0 +1 @@
+export default () => <h1>Hello World</h1>

test/integration/pnpm/test/index.test.js

@@ -0,0 +1,88 @@
+/* eslint-env jest */
+import execa from 'execa'
+import fs from 'fs-extra'
+import os from 'os'
+import path from 'path'
+
+const pnpmExecutable = path.join(
+  __dirname,
+  '..',
+  '..',
+  '..',
+  '..',
+  'node_modules',
+  '.bin',
+  'pnpm'
+)
+const nextPackageDir = path.join(
+  __dirname,
+  '..',
+  '..',
+  '..',
+  '..',
+  'packages',
+  'next'
+)
+const appDir = path.join(__dirname, '..', 'app')
+
+jest.setTimeout(1000 * 60 * 5)
+
+const runPnpm = (cwd, ...args) => execa(pnpmExecutable, [...args], { cwd })
+
+async function usingTempDir(fn) {
+  const folder = path.join(os.tmpdir(), Math.random().toString(36).substring(2))
+  await fs.mkdirp(folder)
+  try {
+    return await fn(folder)
+  } finally {
+    await fs.remove(folder)
+  }
+}
+
+async function packNextTarball(fn) {
+  const { stdout } = await execa(pnpmExecutable, ['pack'], {
+    cwd: nextPackageDir,
+  })
+  const tarballFilename = stdout.match(/.*\.tgz/)[0]
+
+  if (!tarballFilename) {
+    throw new Error(
+      `pnpm failed to pack "next" package tarball in directory ${nextPackageDir}.`
+    )
+  }
+
+  const tarballPath = path.join(nextPackageDir, tarballFilename)
+  try {
+    return await fn(tarballPath)
+  } finally {
+    await fs.unlink(tarballPath)
+  }
+}
+
+describe('pnpm support', () => {
+  it('should build with dependencies installed via pnpm', async () => {
+    // Create a Next.js app in a temporary directory, and install dependencies with pnpm.
+    // "next" is installed by packing a tarball from 'next.js/packages/next', because installing
+    // "next" directly via `pnpm add path/to/next.js/packages/next` results in a symlink:
+    // 'app/node_modules/next' -> 'path/to/next.js/packages/next'. This is undesired since modules
+    // inside "next" would be resolved to the next.js monorepo 'node_modules'; installing from a
+    // tarball avoids this issue.
+    await usingTempDir(async (cwd) => {
+      await packNextTarball(async (nextTarballPath) => {
+        await fs.copy(appDir, cwd)
+        await runPnpm(cwd, 'install')
+        await runPnpm(cwd, 'add', nextTarballPath)
+
+        expect(
+          require(path.join(cwd, 'package.json')).dependencies['next']
+        ).toBe(`file:${nextTarballPath}`)
+        expect(
+          await fs.pathExists(path.join(cwd, 'pnpm-lock.yaml'))
+        ).toBeTruthy()
+
+        const { stdout } = await runPnpm(cwd, 'run', 'build')
+        expect(stdout).toMatch(/Compiled successfully/)
+      })
+    })
+  })
+})