feat(Page): add setCacheEnabled(enabled) to Page object (#1609)

This change adds in the `Page.setCacheEnabled(enabled)` method to toggle ignoring cache for each request.

Fixes #1556.

docs/api.md

@@ -86,6 +86,7 @@
   * [page.reload(options)](#pagereloadoptions)
   * [page.screenshot([options])](#pagescreenshotoptions)
   * [page.select(selector, ...values)](#pageselectselector-values)
+  * [page.setCacheEnabled(enabled)](#pagesetcacheenabledenabled)
   * [page.setContent(html)](#pagesetcontenthtml)
   * [page.setCookie(...cookies)](#pagesetcookiecookies)
   * [page.setDefaultNavigationTimeout(timeout)](#pagesetdefaultnavigationtimeouttimeout)
@@ -1150,6 +1151,12 @@ page.select('select#colors', 'red', 'green', 'blue'); // multiple selections
 
 Shortcut for [page.mainFrame().select()](#frameselectselector-values)
 
+#### page.setCacheEnabled(enabled)
+- `enabled` <[boolean]> sets the `enabled` state of the cache.
+- returns: <[Promise]>
+
+Toggles ignoring cache for each request based on the enabled state. By default, caching is enabled.
+
 #### page.setContent(html)
 - `html` <[string]> HTML markup to assign to the page.
 - returns: <[Promise]>

lib/Page.js

@@ -650,6 +650,14 @@ class Page extends EventEmitter {
     await this._client.send('Page.addScriptToEvaluateOnNewDocument', { source });
   }
 
+  /**
+   * @param {Boolean} enabled
+   * @returns {!Promise}
+   */
+  async setCacheEnabled(enabled = true) {
+    await this._client.send('Network.setCacheDisabled', {cacheDisabled: !enabled});
+  }
+
   /**
    * @param {!Object=} options
    * @return {!Promise<!Buffer>}

test/test.js

@@ -3050,6 +3050,21 @@ describe('Page', function() {
     });
   });
 
+  describe('Page.setCacheEnabled', function() {
+    it('should enable or disable the cache based on the state passed', async({page, server}) => {
+      const responses = new Map();
+      page.on('response', r => responses.set(r.url().split('/').pop(), r));
+
+      await page.goto(server.PREFIX + '/cached/one-style.html', {waitUntil: 'networkidle2'});
+      await page.reload({waitUntil: 'networkidle2'});
+      expect(responses.get('one-style.css').fromCache()).toBe(true);
+
+      await page.setCacheEnabled(false);
+      await page.reload({waitUntil: 'networkidle2'});
+      expect(responses.get('one-style.css').fromCache()).toBe(false);
+    });
+  });
+
   // Printing to pdf is currently only supported in headless
   (headless ? describe : xdescribe)('Page.pdf', function() {
     it('should be able to save file', async({page, server}) => {