fix: force update in setProps (#752)

Author: eddyerburgh

Diff for: packages/test-utils/src/wrapper.js

@@ -664,7 +664,8 @@ export default class Wrapper implements BaseWrapper {
         this.vm.$options.propsData[key] = data[key]
       }
     })
-
+    // $FlowIgnore : Problem with possibly null this.vm
+    this.vm.$forceUpdate()
     // $FlowIgnore : Problem with possibly null this.vm
     orderWatchers(this.vm || this.vnode.context.$root)
     Vue.config.silent = originalConfig

Diff for: test/specs/wrapper/setProps.spec.js

@@ -24,6 +24,20 @@ describeWithShallowAndMount('setProps', mountingMethod => {
     expect(wrapper.find('.prop-2').element.textContent).to.equal(prop2)
   })
 
+  it('sets props and updates when called with same object', () => {
+    const TestComponent = {
+      template: '<div v-if="obj && obj.shouldRender()" />',
+      props: ['obj']
+    }
+    const obj = {
+      shouldRender: () => false
+    }
+    const wrapper = mountingMethod(TestComponent)
+    obj.shouldRender = () => true
+    wrapper.setProps({ obj })
+    expect(wrapper.is('div')).to.equal(true)
+  })
+
   it('throws error if component does not include props key', () => {
     const TestComponent = {
       template: '<div></div>'