fix: does not pass data provided to mount to wrapper component (#1750)

Author: xanf

Diff for: flow/options.flow.js

@@ -3,6 +3,7 @@ declare type Options = {
   attachToDocument?: boolean,
   attachTo?: HTMLElement | string,
   propsData?: Object,
+  data?: Object | Function,
   mocks?: Object,
   methods?: { [key: string]: Function },
   slots?: SlotsObject,
@@ -20,6 +21,7 @@ declare type Options = {
 declare type NormalizedOptions = {
   attachTo?: HTMLElement | string,
   attachToDocument?: boolean,
+  data?: Object | Function,
   propsData?: Object,
   mocks: Object,
   methods: { [key: string]: Function },

Diff for: packages/create-instance/create-instance.js

@@ -125,7 +125,8 @@ export default function createInstance(
   }
 
   // options  "propsData" can only be used during instance creation with the `new` keyword
-  const { propsData, ...rest } = options // eslint-disable-line
+  // "data" should be set only on component under test to avoid reactivity issues
+  const { propsData, data, ...rest } = options // eslint-disable-line
   const Parent = _Vue.extend({
     ...rest,
     ...parentComponentOptions

Diff for: test/specs/mounting-options/data.spec.js

@@ -0,0 +1,24 @@
+import { describeWithShallowAndMount } from '~resources/utils'
+
+describeWithShallowAndMount('options.data', mountingMethod => {
+  const TestComponent = {
+    data: () => ({ foo: 1, bar: 2 }),
+    template: '<div />'
+  }
+
+  it('correctly merges component data and data passed to mount', () => {
+    const wrapper = mountingMethod(TestComponent, { data: () => ({ foo: 3 }) })
+
+    expect(wrapper.vm.foo).toBe(3)
+    expect(wrapper.vm.bar).toBe(2)
+  })
+
+  it('does not fail when data is extracted to local variable', () => {
+    const defaultData = { foo: 3 }
+
+    const wrapper = mountingMethod(TestComponent, { data: () => defaultData })
+
+    expect(wrapper.vm.foo).toBe(3)
+    expect(wrapper.vm.bar).toBe(2)
+  })
+})