angular-demo/node_modules/protractor/example/angular_material/input_spec.js

describe('angular-material input component page', function() {
  const EC = protractor.ExpectedConditions;

  it('Should change input component value', async() => {
    await browser.get('https://material.angular.io/components/input/examples');
      
    await browser.wait(EC.elementToBeClickable($('.mat-button-wrapper>.mat-icon')), 5000);
      
    const emailInputField = $$('.mat-form-field-infix>input').get(1);
      
    await emailInputField.sendKeys('invalid');
      
    expect($('mat-error').isPresent()).toBe(true);
  });
});