diff --git a/packages/@vue/cli-plugin-e2e-webdriverio/__tests__/wdioGenerator.spec.js b/packages/@vue/cli-plugin-e2e-webdriverio/__tests__/wdioGenerator.spec.js
new file mode 100644
index 0000000000..fbc6cdbb56
--- /dev/null
+++ b/packages/@vue/cli-plugin-e2e-webdriverio/__tests__/wdioGenerator.spec.js
@@ -0,0 +1,23 @@
+jest.setTimeout(process.env.APPVEYOR ? 120000 : 60000)
+
+const create = require('@vue/cli-test-utils/createTestProject')
+
+test('should add types to existing tsconfig.json', async () => {
+  const { dir, read, write } = await create('e2e-webdriverio-tsconfig', {
+    plugins: {
+      '@vue/cli-plugin-typescript': {},
+      '@vue/cli-plugin-e2e-webdriverio': {
+        webdrivers: ['chrome']
+      }
+    }
+  })
+  await write('tsconfig.json', JSON.stringify({ compilerOptions: { types: ['some-type'] }}))
+
+  const invoke = require('@vue/cli/lib/invoke')
+  await invoke('e2e-webdriverio', { webdrivers: ['chrome'] }, dir)
+
+  const tsconfig = await read('tsconfig.json')
+  expect(tsconfig).toMatch(/\r?\n$/)
+  expect(JSON.parse(tsconfig)['compilerOptions']['types'])
+    .toEqual(['some-type', 'mocha', '@wdio/mocha-framework', '@wdio/sync'])
+})
diff --git a/packages/@vue/cli-plugin-e2e-webdriverio/generator/index.js b/packages/@vue/cli-plugin-e2e-webdriverio/generator/index.js
index 69879d0611..13032a93d7 100644
--- a/packages/@vue/cli-plugin-e2e-webdriverio/generator/index.js
+++ b/packages/@vue/cli-plugin-e2e-webdriverio/generator/index.js
@@ -21,7 +21,7 @@ const applyTS = module.exports.applyTS = (api, invoking) => {
             }
           }
         }
-        files['tsconfig.json'] = JSON.stringify(parsed, null, 2)
+        files['tsconfig.json'] = JSON.stringify(parsed, null, 2) + '\n'
       }
     })
   }
diff --git a/packages/@vue/cli-plugin-unit-jest/__tests__/jestGenerator.spec.js b/packages/@vue/cli-plugin-unit-jest/__tests__/jestGenerator.spec.js
index 0166aae893..adcadc4dc0 100644
--- a/packages/@vue/cli-plugin-unit-jest/__tests__/jestGenerator.spec.js
+++ b/packages/@vue/cli-plugin-unit-jest/__tests__/jestGenerator.spec.js
@@ -1,4 +1,5 @@
 const generateWithPlugin = require('@vue/cli-test-utils/generateWithPlugin')
+const create = require('@vue/cli-test-utils/createTestProject')
 
 test('base', async () => {
   const { pkg, files } = await generateWithPlugin([
@@ -141,3 +142,20 @@ test('TS + bare + router', async () => {
   expect(spec).toMatch(`const wrapper = mount(App,`)
   expect(spec).toMatch(`expect(wrapper.text()).toMatch(\`Welcome to Your Vue.js App\`)`)
 })
+
+test('add types to existing tsconfig.json', async () => {
+  const { dir, read, write } = await create('unit-jest-tsconfig', {
+    plugins: {
+      '@vue/cli-plugin-typescript': {},
+      '@vue/cli-plugin-unit-jest': {}
+    }
+  })
+  await write('tsconfig.json', JSON.stringify({ compilerOptions: { types: ['some-type'] }}))
+
+  const invoke = require('@vue/cli/lib/invoke')
+  await invoke('unit-jest', {}, dir)
+
+  const tsconfig = await read('tsconfig.json')
+  expect(tsconfig).toMatch(/\r?\n$/)
+  expect(JSON.parse(tsconfig)['compilerOptions']['types']).toEqual(['some-type', 'jest'])
+}, 30000)
diff --git a/packages/@vue/cli-plugin-unit-jest/generator/index.js b/packages/@vue/cli-plugin-unit-jest/generator/index.js
index 843d560850..68873968b8 100644
--- a/packages/@vue/cli-plugin-unit-jest/generator/index.js
+++ b/packages/@vue/cli-plugin-unit-jest/generator/index.js
@@ -87,7 +87,7 @@ const applyTS = (module.exports.applyTS = (api, invoking) => {
         ) {
           parsed.compilerOptions.types.push('jest')
         }
-        files['tsconfig.json'] = JSON.stringify(parsed, null, 2)
+        files['tsconfig.json'] = JSON.stringify(parsed, null, 2) + '\n'
       }
     })
   }
diff --git a/packages/@vue/cli-plugin-unit-mocha/__tests__/mochaGenerator.spec.js b/packages/@vue/cli-plugin-unit-mocha/__tests__/mochaGenerator.spec.js
index 6c6368c4d1..3dce859e47 100644
--- a/packages/@vue/cli-plugin-unit-mocha/__tests__/mochaGenerator.spec.js
+++ b/packages/@vue/cli-plugin-unit-mocha/__tests__/mochaGenerator.spec.js
@@ -1,4 +1,5 @@
 const generateWithPlugin = require('@vue/cli-test-utils/generateWithPlugin')
+const create = require('@vue/cli-test-utils/createTestProject')
 
 test('base', async () => {
   const { pkg, files } = await generateWithPlugin([
@@ -138,3 +139,20 @@ test('TS + bare + router', async () => {
   expect(spec).toMatch(`const wrapper = mount(App,`)
   expect(spec).toMatch(`expect(wrapper.text()).to.include(\`Welcome to Your Vue.js App\`)`)
 })
+
+test('add types to existing tsconfig.json', async () => {
+  const { dir, read, write } = await create('unit-mocha-tsconfig', {
+    plugins: {
+      '@vue/cli-plugin-typescript': {},
+      '@vue/cli-plugin-unit-mocha': {}
+    }
+  })
+  await write('tsconfig.json', JSON.stringify({ compilerOptions: { types: ['some-type'] }}))
+
+  const invoke = require('@vue/cli/lib/invoke')
+  await invoke('unit-mocha', {}, dir)
+
+  const tsconfig = await read('tsconfig.json')
+  expect(tsconfig).toMatch(/\r?\n$/)
+  expect(JSON.parse(tsconfig)['compilerOptions']['types']).toEqual(['some-type', 'mocha', 'chai'])
+}, 30000)
diff --git a/packages/@vue/cli-plugin-unit-mocha/generator/index.js b/packages/@vue/cli-plugin-unit-mocha/generator/index.js
index 204644955f..ab35e769b0 100644
--- a/packages/@vue/cli-plugin-unit-mocha/generator/index.js
+++ b/packages/@vue/cli-plugin-unit-mocha/generator/index.js
@@ -66,7 +66,7 @@ const applyTS = module.exports.applyTS = (api, invoking) => {
             types.push('chai')
           }
         }
-        files['tsconfig.json'] = JSON.stringify(parsed, null, 2)
+        files['tsconfig.json'] = JSON.stringify(parsed, null, 2) + '\n'
       }
     })
   }