diff --git a/packages/test-utils/src/find-vnodes.js b/packages/test-utils/src/find-vnodes.js
index 018571baa..6ee2a1e4d 100644
--- a/packages/test-utils/src/find-vnodes.js
+++ b/packages/test-utils/src/find-vnodes.js
@@ -24,7 +24,8 @@ function findAllVNodes (vnode: VNode, nodes: Array<VNode> = []): Array<VNode> {
 }
 
 function removeDuplicateNodes (vNodes: Array<VNode>): Array<VNode> {
-  return vNodes.filter((vNode, index) => index === vNodes.findIndex(node => vNode.elm === node.elm))
+  const vNodeElms = vNodes.map(vNode => vNode.elm)
+  return vNodes.filter((vNode, index) => index === vNodeElms.indexOf(vNode.elm))
 }
 
 function nodeMatchesRef (node: VNode, refName: string): boolean {
diff --git a/packages/test-utils/src/wrapper.js b/packages/test-utils/src/wrapper.js
index 0f003a42f..9f9b6900a 100644
--- a/packages/test-utils/src/wrapper.js
+++ b/packages/test-utils/src/wrapper.js
@@ -517,7 +517,7 @@ export default class Wrapper implements BaseWrapper {
     Object.keys(data).forEach((key) => {
       // Ignore properties that were not specified in the component options
       // $FlowIgnore : Problem with possibly null this.vm
-      if (!this.vm.$options._propKeys || !this.vm.$options._propKeys.includes(key)) {
+      if (!this.vm.$options._propKeys || !this.vm.$options._propKeys.some(prop => prop === key)) {
         throwError(`wrapper.setProps() called with ${key} property which is not defined on component`)
       }