diff --git a/packages/@vue/cli-service/__tests__/buildWc.spec.js b/packages/@vue/cli-service/__tests__/buildWc.spec.js
index df6965557..ee7470366 100644
--- a/packages/@vue/cli-service/__tests__/buildWc.spec.js
+++ b/packages/@vue/cli-service/__tests__/buildWc.spec.js
@@ -1,4 +1,4 @@
-jest.setTimeout(15000)
+jest.setTimeout(30000)
 
 const path = require('path')
 const portfinder = require('portfinder')
@@ -8,6 +8,7 @@ const create = require('@vue/cli-test-utils/createTestProject')
 const launchPuppeteer = require('@vue/cli-test-utils/launchPuppeteer')
 
 let server, browser, page
+
 test('build as wc', async () => {
   const project = await create('build-wc', defaultPreset)
 
@@ -53,6 +54,41 @@ test('build as wc', async () => {
   expect(h3Text).toMatch('Installed CLI Plugins')
 })
 
+test('build as single wc', async () => {
+  const project = await create('build-single-wc', defaultPreset)
+
+  const { stdout } = await project.run(`vue-cli-service build --target wc --name single-wc`)
+  expect(stdout).toMatch('Build complete.')
+
+  expect(project.has('dist/demo.html')).toBe(true)
+  expect(project.has('dist/single-wc.js')).toBe(true)
+  expect(project.has('dist/single-wc.min.js')).toBe(true)
+
+  const port = await portfinder.getPortPromise()
+  server = createServer({ root: path.join(project.dir, 'dist') })
+
+  await new Promise((resolve, reject) => {
+    server.listen(port, err => {
+      if (err) return reject(err)
+      resolve()
+    })
+  })
+
+  const launched = await launchPuppeteer(`http://localhost:${port}/demo.html`)
+  browser = launched.browser
+  page = launched.page
+
+  const styleCount = await page.evaluate(() => {
+    return document.querySelector('single-wc').shadowRoot.querySelectorAll('style').length
+  })
+  expect(styleCount).toBe(2) // should contain styles from both app and child
+
+  const h1Text = await page.evaluate(() => {
+    return document.querySelector('single-wc').shadowRoot.querySelector('h1').textContent
+  })
+  expect(h1Text).toMatch('Welcome to Your Vue.js App')
+})
+
 afterAll(async () => {
   await browser.close()
   server.close()