littleReact/test/may-dom/ReactEmptyComponent-test.jsx

import PropTypes from '../../lib/ReactPropTypes';
import ReactTestUtils from "../../lib/ReactTestUtils";
import React from '../../src/May';
import { render, unmountComponentAtNode, findDOMNode } from '../../src/may-dom/MayDom';
import {shallowCompare} from '../../src/PureComponent';

var ReactDOM = {
    render: render,
    unmountComponentAtNode: unmountComponentAtNode,
    findDOMNode: findDOMNode
}
React.render = render;


// import React from "../../dist/ReactANU";
// var ReactDOM = React;
// var ReactTestUtils = {
//   renderIntoDocument: function (element) {
//     var div = document.createElement("div");
//     return React.render(element, div);
//   }
// };
//https://github.com/facebook/react/blob/master/src/isomorphic/children/__tests__/ReactChildren-test.js

describe("ReactComponent", function() {
    // this.timeout(200000);


    it("should not produce child DOM nodes for null and false", function() {
        class Component1 extends React.Component {
            render() {
                return null;
            }
        }

        class Component2 extends React.Component {
            render() {
                return false;
            }
        }

        var container1 = document.createElement("div");
        ReactDOM.render(<Component1 />, container1);
        expect(container1.children.length).toBe(0);

        var container2 = document.createElement("div");
        ReactDOM.render(<Component2 />, container2);
        expect(container2.children.length).toBe(0);
    });

    it("works when switching components", () => {
        var assertions = 0;

        class Inner extends React.Component {
            render() {
                return <span />;
            }

            componentDidMount() {
                // Make sure the DOM node resolves properly even if we're replacing a
                // `null` component
                expect(ReactDOM.findDOMNode(this)).not.toBe(null);
                assertions++;
            }

            componentWillUnmount() {
                // Even though we're getting replaced by `null`, we haven't been
                // replaced yet!
                expect(ReactDOM.findDOMNode(this)).not.toBe(null);
                assertions++;
            }
        }

        class Wrapper extends React.Component {
            render() {
                return this.props.showInner ? <Inner /> : null;
            }
        }

        var el = document.createElement("div");
        var component;

        // Render the <Inner /> component...
        component = ReactDOM.render(<Wrapper showInner={true} />, el);
        expect(ReactDOM.findDOMNode(component)).not.toBe(null);

        // Switch to null...
        component = ReactDOM.render(<Wrapper showInner={false} />, el);
        // expect(ReactDOM.findDOMNode(component).nodeName).toBe("#comment");
        // ...then switch back.
        component = ReactDOM.render(<Wrapper showInner={true} />, el);
        expect(ReactDOM.findDOMNode(component)).not.toBe(null);

        expect(assertions).toBe(3);
       
    });
    it("preserves the dom node during updates", () => {
        class Empty extends React.Component {
            render() {
                return null;
            }
        }

        var container = document.createElement("div");

        ReactDOM.render(<Empty />, container);
        var noscript1 = container.firstChild;
       
        expect(noscript1.nodeName).toBe("#comment");
       

        // This update shouldn't create a DOM node
        ReactDOM.render(<Empty />, container);
        var noscript2 = container.firstChild;
       
        expect(noscript2.nodeName).toBe("#comment");
       

        expect(noscript1).toBe(noscript2);
    });
});