refactor app directory structure and add tests

tests/node_modules/nightwatch/lib/page-object/page.js

@@ -0,0 +1,66 @@
+var PageUtils = require('./page-utils.js');
+var CommandWrapper = require('./command-wrapper.js');
+
+/**
+ * Class that all pages subclass from
+ *
+ * @param {Object} options Page options defined in page object
+ * @constructor
+ */
+function Page(options, commandLoader, api, client) {
+  this.commandLoader = commandLoader;
+  this.api = api;
+  this.client = client;
+  this.name = options.name;
+  this.url = options.url;
+
+  PageUtils
+    .createProps(this, options.props || {})
+    .createElements(this, options.elements || {})
+    .createSections(this, options.sections || {})
+    .addCommands(this, options.commands || []);
+
+  CommandWrapper.addWrappedCommands(this, this.commandLoader);
+}
+
+Page.prototype = {
+  /**
+   * Returns the url passed as an argument (or null if no arguments are passed).
+   *  If the supplied url is a function, it invokes that function with the page as its context.
+   *
+   * @method getUrl
+   * @param {string} url
+   * @returns {string|null}
+   */
+  getUrl: function(url) {
+    if (typeof url === 'function') {
+      return url.call(this);
+    } else if (typeof url === 'string') {
+      return url;
+    }
+
+    return null;
+  },
+
+  /**
+   * This command is an alias to url and also a convenience method because when called without any arguments
+   *  it performs a call to .url() with passing the value of `url` property on the page object.
+   * Uses `url` protocol command.
+   *
+   * @method navigate
+   * @param {Object} [url=this.url] Url to navigate to.
+   * @param {function} [callback] Optional callback function to be called when the command finishes.
+   * @returns {*}
+   */
+  navigate: function(url, callback) {
+    var goToUrl = this.getUrl(url || this.url);
+    if (goToUrl === null) {
+      throw new Error('Invalid URL: You must either add a url property to "' +
+        this.name + '" or provide a url as an argument');
+    }
+    this.api.url(goToUrl, callback);
+    return this;
+  }
+};
+
+module.exports = Page;