Add ScrollPageToElement to action_runner.

telemetry/telemetry/internal/actions/action_runner_unittest.py

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 import mock
 import unittest
 
 from telemetry.core import exceptions
 from telemetry import decorators
 from telemetry.internal.actions import action_runner as action_runner_module
 from telemetry.internal.actions import page_action
@@ skipping 242 matching lines @@
 
     action_runner.ExecuteJavaScript('valueSettableByTest = 3;')
     action_runner.TapElement(
         element_function='document.body.firstElementChild')
     self.assertEqual(3, action_runner.EvaluateJavaScript('valueToTest'))
 
     def WillFail():
       action_runner.TapElement('#notfound')
     self.assertRaises(exceptions.EvaluateException, WillFail)
 
+
+  def testScrollToElement(self):
+    if not page_action.IsGestureSourceTypeSupported(

[nednguyen, 2016/10/14 18:05:59]

I think we don't need this. When I patch your CL & run the test on my Mac, it
did not run because of this check. Removing this test make it runs the actual
action just fine.

[rnephew (Reviews Here), 2016/10/14 18:08:56]

Done.

+        self._tab, 'touch'):
+      return
+
+    self.Navigate('page_with_swipeables.html')
+    action_runner = action_runner_module.ActionRunner(self._tab,
+                                                      skip_waits=True)
+
+    off_screen_element = 'document.querySelectorAll("#off-screen")[0]'
+    top_bottom_element = 'document.querySelector("#top-bottom")'
+    viewport_comparator_js_template = '''
+      (function(elem) {
+        var rect = elem.getBoundingClientRect();
+
+        if (rect.bottom < 0) {
+          // The bottom of the element is above the viewport.
+          return -1;
+        }
+        if (rect.top - window.innerHeight > 0) {
+          // rect.top provides the pixel offset of the element from the
+          // top of the page. Because that exceeds the viewport's height,
+          // we know that the element is below the viewport.
+          return 1;
+        }
+        return 0;
+      })(
+    '''
+    viewport_comparator_off_screen_js = (
+        viewport_comparator_js_template + '%s);' % off_screen_element)
+    viewport_comparator_top_bottom_js = (
+        viewport_comparator_js_template + '%s);' % top_bottom_element)
+
+    self.assertEqual(
+        action_runner.EvaluateJavaScript(viewport_comparator_off_screen_js), 1)
+    action_runner.ScrollPageToElement(selector='#off-screen',
+                                      speed_in_pixels_per_second=5000)
+    self.assertEqual(
+        action_runner.EvaluateJavaScript(viewport_comparator_off_screen_js), 0)
+
+    self.assertEqual(
+        action_runner.EvaluateJavaScript(viewport_comparator_top_bottom_js), -1)
+    action_runner.ScrollPageToElement(selector='#top-bottom',
+                                      speed_in_pixels_per_second=5000)
+    self.assertEqual(
+        action_runner.EvaluateJavaScript(viewport_comparator_top_bottom_js), 0)
+
+
   @decorators.Disabled('android',   # crbug.com/437065.
                        'chromeos')  # crbug.com/483212.
   def testScroll(self):
     if not page_action.IsGestureSourceTypeSupported(
         self._tab, 'touch'):
       return
 
     self.Navigate('page_with_swipeables.html')
     action_runner = action_runner_module.ActionRunner(self._tab,
                                                       skip_waits=True)
@@ skipping 86 matching lines @@
     with self.assertRaises(FooException):
       with action_runner_module.Interaction(
           self.mock_action_runner, label='ABC', flags=[]):
         raise FooException()
 
     # Test that the end console.timeEnd(...) isn't called because exception was
     # raised.
     expected_calls = [
         mock.call.ExecuteJavaScript('console.time("Interaction.ABC");')]
     self.assertEqual(expected_calls, self.mock_action_runner.mock_calls)