Simple protractor test which find an element, clicks it, then checks it's text value.

protractorClickTest.js

describe('click to reverse', function () {
  var btn;

  it('Reverses the button label on click', function () {
    // load the page
    browser.get('http://localhost:63342/protractorDemo/index.html');

    // Find the button
    btn = element(by.binding('click.btnText'));

    // Click it
    btn.click();

    // Test the label
    expect(btn.getText()).toEqual('esrever ot kcilC');
  });

  it('Changes the label back on the next click', function () {
    // Clicks it again
    btn.click();

    // Test the label
    expect(btn.getText()).toEqual('Click to reverse');
  });
});