Add provide function value and test

Author: Austio

Diff for: src/lib/addProvide.js

@@ -1,10 +1,15 @@
 function addProvide (component, options) {
-  const provideOption = Object.assign({}, options.provide)
+  const provide = typeof options.provide === 'function'
+    ? options.provide
+    : Object.assign({}, options.provide)
+
   delete options.provide
 
   const originalBeforeCreate = component.beforeCreate
   component.beforeCreate = function beforeCreate () {
-    this._provided = provideOption
+    this._provided = typeof provide === 'function'
+      ? provide.call(this)
+      : provide
 
     if (originalBeforeCreate) {
       originalBeforeCreate.call(this)

Diff for: test/unit/specs/mount/options/provide.spec.js

@@ -2,17 +2,29 @@ import mount from '../../../../../src/mount'
 import ComponentWithInject from '../../../../resources/components/component-with-inject.vue'
 
 describe('provide option in mount', () => {
-  it('provides value which is injected by mounted component', () => {
+  it('provides objects which is injected by mounted component', () => {
     const wrapper = mount(ComponentWithInject, {
-      provide: { fromMount: 'providedValue' }
+      provide: { fromMount: 'objectValue' }
     })
 
-    expect(wrapper.text()).to.contain('providedValue')
+    expect(wrapper.text()).to.contain('objectValue')
+  })
+
+  it('provides function which is injected by mounted component', () => {
+    const wrapper = mount(ComponentWithInject, {
+      provide () {
+        return {
+          fromMount: 'functionValue'
+        }
+      }
+    })
+
+    expect(wrapper.text()).to.contain('functionValue')
   })
 
   it('supports beforeCreate in component', () => {
     const wrapper = mount(ComponentWithInject, {
-      provide: { fromMount: 'providedValue' }
+      provide: { fromMount: '_' }
     })
 
     expect(wrapper.vm.setInBeforeCreate).to.equal('created')