[Hidden] Change children type to allow many and add children tests

src/Hidden/HiddenCss.js

@@ -2,7 +2,6 @@
 
 import React from 'react';
 import warning from 'warning';
-import classNames from 'classnames';
 import { keys as breakpoints } from '../styles/createBreakpoints';
 import { capitalizeFirstLetter } from '../utils/helpers';
 import withStyles from '../styles/withStyles';
@@ -89,13 +88,7 @@ function HiddenCss(props: AllProps) {
     className.push(classes[`only${capitalizeFirstLetter(only)}`]);
   }
 
-  if (!React.isValidElement(children)) {
-    return null;
-  }
-
-  return React.cloneElement(children, {
-    className: classNames(children.props.className, className.join(' ')),
-  });
+  return <span className={className}>{children}</span>;
 }
 
 export default withStyles(styles, { name: 'MuiHiddenCss' })(HiddenCss);

src/Hidden/HiddenCss.spec.js

@@ -5,12 +5,14 @@ import { assert } from 'chai';
 import { createShallow, getClasses } from '../test-utils';
 import HiddenCss from './HiddenCss';
 
+const Foo = () => <div>bar</div>;
+
 describe('<HiddenCss />', () => {
   let shallow;
   let classes;
 
   before(() => {
-    shallow = createShallow();
+    shallow = createShallow({ untilSelector: 'span' });
     classes = getClasses(
       <HiddenCss>
         <div />
@@ -25,7 +27,11 @@ describe('<HiddenCss />', () => {
           <div className="foo" />
         </HiddenCss>,
       );
-      assert.strictEqual(wrapper.props().className, `foo ${classes.onlySm}`);
+      assert.strictEqual(wrapper.type(), 'span');
+      assert.isTrue(wrapper.hasClass(classes.onlySm));
+      const div = wrapper.childAt(0);
+      assert.strictEqual(div.type(), 'div');
+      assert.strictEqual(div.props().className, 'foo');
     });
 
     it('should be ok with mdDown', () => {
@@ -34,7 +40,7 @@ describe('<HiddenCss />', () => {
           <div className="foo" />
         </HiddenCss>,
       );
-      assert.strictEqual(wrapper.props().className, `foo ${classes.mdDown}`);
+      assert.isTrue(wrapper.hasClass(classes.mdDown));
     });
 
     it('should be ok with mdUp', () => {
@@ -43,13 +49,49 @@ describe('<HiddenCss />', () => {
           <div className="foo" />
         </HiddenCss>,
       );
-      assert.strictEqual(wrapper.props().className, `foo ${classes.mdUp}`);
+      assert.isTrue(wrapper.hasClass(classes.mdUp));
     });
   });
 
   describe('prop: children', () => {
     it('should work when empty', () => {
-      shallow(<HiddenCss mdUp />);
+      const wrapper = shallow(<HiddenCss mdUp />);
+      assert.strictEqual(wrapper.type(), 'span');
+      assert.isTrue(wrapper.hasClass(classes.mdUp));
+      assert.isNull(wrapper.childAt(0).type());
+    });
+
+    it('should work when text Node', () => {
+      const wrapper = shallow(<HiddenCss mdUp>foo</HiddenCss>);
+      assert.strictEqual(wrapper.type(), 'span');
+      assert.isTrue(wrapper.hasClass(classes.mdUp));
+      assert.strictEqual(wrapper.childAt(0).text(), 'foo');
+    });
+
+    it('should work when Element', () => {
+      const wrapper = shallow(
+        <HiddenCss mdUp>
+          <Foo />
+        </HiddenCss>,
+      );
+      assert.strictEqual(wrapper.type(), 'span');
+      assert.isTrue(wrapper.hasClass(classes.mdUp));
+      assert.isTrue(wrapper.childAt(0).is(Foo));
+    });
+
+    it('should work when mixed ChildrenArray', () => {
+      const wrapper = shallow(
+        <HiddenCss mdUp>
+          <Foo />
+          <Foo />
+          foo
+        </HiddenCss>,
+      );
+      assert.strictEqual(wrapper.type(), 'span');
+      assert.isTrue(wrapper.hasClass(classes.mdUp));
+      assert.isTrue(wrapper.childAt(0).is(Foo));
+      assert.isTrue(wrapper.childAt(1).is(Foo));
+      assert.strictEqual(wrapper.childAt(2).text(), 'foo');
     });
   });
 });

src/Hidden/HiddenJs.spec.js

@@ -8,6 +8,8 @@ import HiddenJs from './HiddenJs';
 import type { Breakpoint } from '../styles/createBreakpoints';
 import Typography from '../Typography';
 
+const Foo = () => <div>bar</div>;
+
 describe('<HiddenJs />', () => {
   let shallow;
 
@@ -41,12 +43,26 @@ describe('<HiddenJs />', () => {
       it(descriptions[upDownOnly], () => {
         const props = { width, [prop]: breakpoint };
 
-        // children
+        // Node
         let wrapper = shallow(<HiddenJs {...props}>foo</HiddenJs>);
         assert.isNull(wrapper.type(), 'should render null');
 
-        // element
-        wrapper = shallow(<HiddenJs {...props}>foo</HiddenJs>);
+        // Element
+        wrapper = shallow(
+          <HiddenJs {...props}>
+            <Foo />
+          </HiddenJs>,
+        );
+        assert.isNull(wrapper.type(), 'should render null');
+
+        // ChildrenArray
+        wrapper = shallow(
+          <HiddenJs {...props}>
+            <Foo />
+            <Foo />
+            foo
+          </HiddenJs>,
+        );
         assert.isNull(wrapper.type(), 'should render null');
       });
     });

src/Hidden/types.js

@@ -1,13 +1,13 @@
 // @flow
 
-import type { Element } from 'react';
+import type { ChildrenArray, Node } from 'react';
 import type { Breakpoint } from '../styles/createBreakpoints';
 
 export type HiddenProps = {
   /**
    * The content of the component.
    */
-  children?: Element<*>,
+  children?: $ReadOnlyArray<ChildrenArray<Node>>,
   /**
    * @ignore
    */