✅ Add jest for testing

.babelrc

@@ -0,0 +1,22 @@
+{
+  "presets": [
+    ["env", {
+      "targets": {
+        "browsers": [
+        "last 2 Chrome versions",
+        ]
+      }
+    }]
+  ],
+  "env": {
+    "test": {
+      "presets": [
+        ["env", {
+          "targets": {
+            "node": "current"
+          }
+        }]
+      ]
+    }
+  }
+}

package.json

@@ -7,7 +7,10 @@
   "unpkg": "dist/vue-promised.js",
   "browser": "dist/vue-promised.js",
   "scripts": {
-    "test": "echo \"Error: no test specified\" && exit 1",
+    "lint": "eslint --color --ext=js,html src test example docs",
+    "unit": "jest",
+    "dev": "npm run unit -- --watchAll",
+    "test": "npm run lint && npm run unit",
     "prepublishOnly": "rollit"
   },
   "files": [
@@ -28,5 +31,35 @@
     "type": "git",
     "url": "git+https://github.com/posva/vue-promised.git"
   },
-  "license": "MIT"
+  "license": "MIT",
+  "devDependencies": {
+    "@vue/test-utils": "^1.0.0-beta.11",
+    "babel-jest": "^22.1.0",
+    "babel-preset-env": "^1.6.1",
+    "codecov": "^3.0.0",
+    "eslint": "^4.16.0",
+    "eslint-config-posva": "^1.3.2",
+    "jest": "^22.1.4",
+    "vue": "^2.5.13",
+    "vue-jest": "^2.0.0",
+    "vue-template-compiler": "^2.5.13"
+  },
+  "jest": {
+    "collectCoverage": true,
+    "moduleFileExtensions": [
+      "js",
+      "json",
+      "vue"
+    ],
+    "transform": {
+      "^.+\\.js$": "<rootDir>/node_modules/babel-jest",
+      ".*\\.(vue)$": "<rootDir>/node_modules/vue-jest"
+    },
+    "coveragePathIgnorePatterns": [
+      "<rootDir>/test/*.js",
+      "<rootDir>/test/utils/Helper.vue",
+      "<rootDir>/test/.*.js",
+      "<rootDir>/test/*/*.js"
+    ]
+  }
 }

test/index.spec.js

@@ -0,0 +1,23 @@
+import { mount } from '@vue/test-utils'
+import Promised from '../src'
+import Helper from './utils/Helper'
+
+const tick = () => new Promise(r => setImmediate(r))
+
+describe('Tweezing', () => {
+  let wrapper
+  let promise
+  beforeEach(() => {
+    promise = Promise.resolve('foo')
+    wrapper = mount(Helper, {
+      propsData: {
+        promise,
+      },
+    })
+  })
+
+  test('displays a loading screen waiting for the promise', async () => {
+    await tick()
+    console.log(wrapper.text())
+  })
+})

test/utils/Helper.vue

@@ -0,0 +1,18 @@
+<template>
+  <Promised v-bind="$props">
+    <h1>loading</h1>
+    <!-- The default scoped slots will be used as the result -->
+    <h1 slot-scope="data">{{ data }}</h1>
+    <!-- The 'error' named scoped slots will be used if there is an error -->
+    <h1 slot="error" slot-scope="error">{{ error.message }}</h1>
+  </Promised>
+</template>
+
+<script>
+import Promised from '../../src'
+
+export default {
+  props: ['promise', 'promises'],
+  components: { Promised },
+}
+</script>