Make sure to copy AMP SSG files during export

packages/next/export/index.ts

@@ -3,6 +3,7 @@ import findUp from 'find-up'
 import {
   copyFile as copyFileOrig,
   existsSync,
+  exists as existsOrig,
   mkdir as mkdirOrig,
   readFileSync,
   writeFileSync,
@@ -37,6 +38,7 @@ import { normalizePagePath } from '../next-server/server/normalize-page-path'
 
 const copyFile = promisify(copyFileOrig)
 const mkdir = promisify(mkdirOrig)
+const exists = promisify(existsOrig)
 
 const createProgress = (total: number, label = 'Exporting') => {
   let curProgress = 0
@@ -381,12 +383,21 @@ export default async function(
             subFolders && route !== '/index' ? `${sep}index` : ''
           }.html`
         )
+        const ampHtmlDest = join(
+          outDir,
+          `${route}.amp${subFolders ? `${sep}index` : ''}.html`
+        )
         const jsonDest = join(pagesDataDir, `${route}.json`)
 
         await mkdir(dirname(htmlDest), { recursive: true })
         await mkdir(dirname(jsonDest), { recursive: true })
         await copyFile(`${orig}.html`, htmlDest)
         await copyFile(`${orig}.json`, jsonDest)
+
+        if (await exists(`${orig}.amp.html`)) {
+          await mkdir(dirname(ampHtmlDest), { recursive: true })
+          await copyFile(`${orig}.amp.html`, ampHtmlDest)
+        }
       })
     )
   }

test/integration/amphtml-ssg/test/index.test.js

@@ -11,6 +11,7 @@ import {
   launchApp,
   killApp,
   nextStart,
+  nextExport,
 } from 'next-test-utils'
 
 const appDir = join(__dirname, '../')
@@ -21,6 +22,12 @@ let app
 
 jasmine.DEFAULT_TIMEOUT_INTERVAL = 1000 * 60 * 2
 
+const fsExists = file =>
+  fs
+    .access(file)
+    .then(() => true)
+    .catch(() => false)
+
 const runTests = (isDev = false) => {
   it('should load an amp first page correctly', async () => {
     const html = await renderViaHTTP(appPort, '/amp')
@@ -51,12 +58,6 @@ const runTests = (isDev = false) => {
   })
 
   if (!isDev) {
-    const fsExists = file =>
-      fs
-        .access(file)
-        .then(() => true)
-        .catch(() => false)
-
     const builtPage = file => join(builtServerPagesDir, file)
 
     it('should output prerendered files correctly during build', async () => {
@@ -121,4 +122,31 @@ describe('AMP SSG Support', () => {
     afterAll(() => killApp(app))
     runTests(true)
   })
+  describe('export mode', () => {
+    let buildId
+
+    beforeAll(async () => {
+      await nextBuild(appDir)
+      await nextExport(appDir, { outdir: join(appDir, 'out') })
+      buildId = await fs.readFile(join(appDir, '.next/BUILD_ID'), 'utf8')
+    })
+
+    it('should have copied SSG files correctly', async () => {
+      const outFile = file => join(appDir, 'out', file)
+
+      expect(await fsExists(outFile('amp.html'))).toBe(true)
+      expect(await fsExists(outFile('index.html'))).toBe(true)
+      expect(await fsExists(outFile('hybrid.html'))).toBe(true)
+      expect(await fsExists(outFile('amp.amp.html'))).toBe(false)
+      expect(await fsExists(outFile('hybrid.amp.html'))).toBe(true)
+
+      expect(
+        await fsExists(outFile(join('_next/data', buildId, 'amp.json')))
+      ).toBe(true)
+
+      expect(
+        await fsExists(outFile(join('_next/data', buildId, 'hybrid.json')))
+      ).toBe(true)
+    })
+  })
 })