fix: accept all valid components in stubs option (#389)

Author: eddyerburgh

src/lib/stub-components.js

@@ -4,12 +4,15 @@ import Vue from 'vue'
 import { compileToFunctions } from 'vue-template-compiler'
 import { throwError } from './util'
 
+function isVueComponent (comp) {
+  return comp && (comp.render || comp.template || comp.options)
+}
+
 function isValidStub (stub: any) {
   return !!stub &&
-      (typeof stub === 'string' ||
+      typeof stub === 'string' ||
       (stub === true) ||
-      (typeof stub === 'object' &&
-      typeof stub.render === 'function'))
+      (isVueComponent(stub))
 }
 
 function isRequiredComponent (name) {

test/unit/specs/mount/options/stubs.spec.js

@@ -2,7 +2,9 @@ import { mount, config } from '~vue-test-utils'
 import ComponentWithChild from '~resources/components/component-with-child.vue'
 import ComponentWithNestedChildren from '~resources/components/component-with-nested-children.vue'
 import Component from '~resources/components/component.vue'
+import ComponentAsAClass from '~resources/components/component-as-a-class.vue'
 import { createLocalVue } from '~vue-test-utils'
+import Vue from 'vue'
 
 describe('mount.stub', () => {
   let info
@@ -22,6 +24,20 @@ describe('mount.stub', () => {
     config.stubs = configStubsSave
   })
 
+  it('accepts valid component stubs', () => {
+    const ComponentWithRender = { render: h => h('div') }
+    const ComponentWithoutRender = { template: '<div></div>' }
+    const ExtendedComponent = Vue.extend({ template: '<div></div>' })
+    mount(ComponentWithChild, {
+      stubs: {
+        ChildComponent: ComponentAsAClass,
+        ChildComponent2: ComponentWithRender,
+        ChildComponent3: ComponentWithoutRender,
+        ChildComponent4: ExtendedComponent
+      }
+    })
+  })
+
   it('replaces component with template string ', () => {
     const wrapper = mount(ComponentWithChild, {
       stubs: {