Make slide toggle e2e test take screenshots when ripple disappeared (#3171)

Author: tinayuangao

e2e/components/slide-toggle/slide-toggle.e2e.ts

@@ -1,4 +1,4 @@
-import {browser, element, by, Key} from 'protractor';
+import {browser, element, by, Key, ExpectedConditions} from 'protractor';
 import {expectToExist} from '../../util/asserts';
 import {screenshot} from '../../screenshot';
 
@@ -21,7 +21,9 @@ describe('slide-toggle', () => {
     getNormalToggle().click();
 
     expect(inputEl.getAttribute('checked')).toBeTruthy('Expect slide-toggle to be checked');
-    screenshot();
+    browser.wait(ExpectedConditions.not(
+      ExpectedConditions.presenceOf(element(by.css('div.mat-ripple-element')))))
+      .then(() => screenshot());
   });
 
   it('should change the checked state on click', () => {
@@ -32,7 +34,9 @@ describe('slide-toggle', () => {
     getNormalToggle().click();
 
     expect(inputEl.getAttribute('checked')).toBeTruthy('Expect slide-toggle to be checked');
-    screenshot();
+    browser.wait(ExpectedConditions.not(
+      ExpectedConditions.presenceOf(element(by.css('div.mat-ripple-element')))))
+      .then(() => screenshot());
   });
 
   it('should not change the checked state on click when disabled', () => {
@@ -43,7 +47,9 @@ describe('slide-toggle', () => {
     element(by.css('#disabled-slide-toggle')).click();
 
     expect(inputEl.getAttribute('checked')).toBeFalsy('Expect slide-toggle to be unchecked');
-    screenshot();
+    browser.wait(ExpectedConditions.not(
+      ExpectedConditions.presenceOf(element(by.css('div.mat-ripple-element')))))
+      .then(() => screenshot());
   });
 
   it('should move the thumb on state change', () => {
@@ -57,7 +63,9 @@ describe('slide-toggle', () => {
     let newX = thumbEl.getLocation().then(pos => pos.x);
 
     expect(previousX).not.toBe(newX);
-    screenshot();
+    browser.wait(ExpectedConditions.not(
+      ExpectedConditions.presenceOf(element(by.css('div.mat-ripple-element')))))
+      .then(() => screenshot());
   });
 
   it('should toggle the slide-toggle on space key', () => {