Author: Add unit tests

editor/sidebar/post-author/index.js

@@ -18,7 +18,7 @@ import './style.scss';
 import { getEditedPostAttribute } from '../../selectors';
 import { editPost } from '../../actions';
 
-class PostAuthor extends Component {
+export class PostAuthor extends Component {
 	constructor() {
 		super( ...arguments );
 

editor/sidebar/post-author/test/index.js

@@ -0,0 +1,102 @@
+/**
+ * External dependencies
+ */
+import { shallow } from 'enzyme';
+
+/**
+ * Internal dependencies
+ */
+import { PostAuthor } from '../';
+
+describe( 'PostAuthor', () => {
+	const users = {
+		data: [
+			{
+				id: 1,
+				name: 'admin',
+				capabilities: {
+					level_1: true,
+				},
+			},
+			{
+				id: 2,
+				name: 'subscriber',
+				capabilities: {
+					level_0: true,
+				},
+			},
+			{
+				id: 3,
+				name: 'andrew',
+				capabilities: {
+					level_1: true,
+				},
+			},
+		],
+	};
+
+	describe( '#getAuthors()', () => {
+		it( 'returns empty array on unknown users', () => {
+			const wrapper = shallow( <PostAuthor users={ {} } /> );
+
+			const authors = wrapper.instance().getAuthors();
+
+			expect( authors ).toEqual( [] );
+		} );
+
+		it( 'filters users to authors', () => {
+			const wrapper = shallow( <PostAuthor users={ users } /> );
+
+			const authors = wrapper.instance().getAuthors();
+
+			expect( authors.map( ( author ) => author.id ).sort() ).toEqual( [ 1, 3 ] );
+		} );
+	} );
+
+	describe( '#render()', () => {
+		it( 'should not render anything if users unknown', () => {
+			const wrapper = shallow( <PostAuthor users={ {} } /> );
+
+			expect( wrapper.type() ).toBe( null );
+		} );
+
+		it( 'should not render anything if single user', () => {
+			const wrapper = shallow(
+				<PostAuthor users={ { data: users.data.slice( 0, 1 ) } } />
+			);
+
+			expect( wrapper.type() ).toBe( null );
+		} );
+
+		it( 'should not render anything if single filtered user', () => {
+			const wrapper = shallow(
+				<PostAuthor users={ { data: users.data.slice( 0, 2 ) } } />
+			);
+
+			expect( wrapper.type() ).toBe( null );
+		} );
+
+		it( 'should render select control', () => {
+			const wrapper = shallow( <PostAuthor users={ users } /> );
+
+			expect( wrapper.find( 'select' ).length ).not.toBe( 0 );
+		} );
+
+		it( 'should update author', () => {
+			const onUpdateAuthor = jest.fn();
+			const wrapper = shallow(
+				<PostAuthor
+					users={ users }
+					onUpdateAuthor={ onUpdateAuthor } />
+			);
+
+			wrapper.find( 'select' ).simulate( 'change', {
+				target: {
+					value: '3',
+				},
+			} );
+
+			expect( onUpdateAuthor ).toHaveBeenCalledWith( 3 );
+		} );
+	} );
+} );