Fix unit test coverage

Author: ganderzz

src/ScrollArea.jsx

@@ -1,4 +1,4 @@
-import React, { Component, createRef } from "react";
+import React, { Component } from "react";
 import { ScrollToContext } from "./ScrollTo";
 import generateId from "./utilities/generateId";
 
@@ -13,7 +13,8 @@ export function createRefPoly() {
 }
 
 export class ScrollArea extends Component {
-  node = createRef ? createRef() : createRefPoly();
+  // Using React.createRef so we can easily unit test this
+  node = React.createRef ? React.createRef() : createRefPoly();
   id = this.props.id || generateId();
 
   componentDidMount() {

src/ScrollTo.jsx

@@ -1,11 +1,12 @@
-import React, { Component, createContext, isValidElement } from "react";
-import { findDOMNode } from "react-dom";
+import React, { Component, isValidElement } from "react";
+import ReactDOM from "react-dom";
 import { relative } from "./utilities/relative";
 import createReactContext from "create-react-context";
 
-export const ScrollToContext = !createContext
-  ? createReactContext({})
-  : createContext({});
+/* istanbul ignore next */
+export const ScrollToContext = React.createContext
+  ? React.createContext({}) /* istanbul ignore next */
+  : createReactContext({});
 
 /**
  * Component that uses render props to inject
@@ -63,9 +64,12 @@ class ScrollTo extends Component {
     const top = ScrollTo._parseLocation(options.y, node, true);
     const left = ScrollTo._parseLocation(options.x, node, false);
 
+    /* istanbul ignore next */
     if (isValidElement(node)) {
-      const rNode = findDOMNode(node);
+      /* istanbul ignore next */
+      const rNode = ReactDOM.findDOMNode(node);
 
+      /* istanbul ignore next */
       if (rNode) {
         node = rNode;
       }

src/tests/ScrollArea.spec.jsx

@@ -79,4 +79,26 @@ describe("Test Scroll Area.", () => {
 
     expect(ref.current).toBeTruthy();
   });
+
+  it("Should handle a null element passed to createRef", () => {
+    const ref = createRefPoly();
+
+    ref(null);
+
+    expect(ref.current).toBeFalsy();
+  });
+
+  it("Should use createRefPoly() when createRef() doesn't exist", () => {
+    const rCreateRefTemp = React.createRef;
+    React.createRef = false;
+
+    const { container, debug } = render(
+      <BaseScrollArea addScrollArea={() => {}} removeScrollArea={() => {}}>
+        <h1>Test</h1>
+      </BaseScrollArea>
+    );
+
+    expect(true).toBeTruthy();
+    React.createRef = rCreateRefTemp;
+  });
 });

src/tests/ScrollTo.spec.jsx

@@ -1,10 +1,8 @@
 import React from "react";
 import { render, cleanup, fireEvent } from "react-testing-library";
 import { shallow } from "enzyme";
-import ScrollTo from "../ScrollTo";
 import createReactContext from "create-react-context";
-
-const { findDOMNode } = jest.requireMock("react-dom");
+import ScrollTo from "../ScrollTo";
 
 afterEach(cleanup);
 
@@ -177,7 +175,7 @@ describe("Test render prop.", () => {
     ]);
   });
 
-  it("Should scroll by ref when provided", () => {
+  it("Should scroll by ref when a DOM node is provided", () => {
     const refDOM = React.createRef ? React.createRef() : createReactContext();
     const { getByText } = render(
       <ScrollTo>
@@ -202,6 +200,34 @@ describe("Test render prop.", () => {
     expect(refDOM.current).toMatchSnapshot();
   });
 
+  it("Should scroll by ref when a React node is provided", () => {
+    const refDOM = {};
+    const MyElement = ({ children, ...props }) => (
+      <div {...props}>{children}</div>
+    );
+
+    const { getByText } = render(
+      <ScrollTo>
+        {({ scrollTo }) => (
+          <>
+            <MyElement
+              onClick={() => scrollTo({ ref: refDOM, x: 100, y: 200 })}
+            >
+              myBtn
+            </MyElement>
+
+            <div ref={() => {}}>test</div>
+          </>
+        )}
+      </ScrollTo>
+    );
+
+    const buttonEl = getByText("myBtn");
+    fireEvent.click(buttonEl);
+
+    expect(refDOM.current).toMatchSnapshot();
+  });
+
   it("Should handle invalid ref", () => {
     const refDOM = {};
     const { getByText } = render(
@@ -230,7 +256,7 @@ describe("Test render prop.", () => {
 
   it("Should handle using the relative() function", () => {
     const refDOM = React.createRef ? React.createRef() : createReactContext();
-    const { getByText, baseElement } = render(
+    const { getByText } = render(
       <ScrollTo>
         {({ scrollTo, relative }) => (
           <>

src/tests/__snapshots__/ScrollTo.spec.jsx.snap

@@ -26,12 +26,14 @@ Object {
 }
 `;
 
-exports[`Test render prop. Should scroll by ref when provided 1`] = `
+exports[`Test render prop. Should scroll by ref when a DOM node is provided 1`] = `
 <div>
   test
 </div>
 `;
 
+exports[`Test render prop. Should scroll by ref when a React node is provided 1`] = `undefined`;
+
 exports[`Test render prop. Should update scroll position of ScrollArea's if present, rather than window 1`] = `
 Object {
   "scrollLeft": 100,