ggleClass('hidden', false, actualTooltip);
        assert.isFalse(isHidden(actualTooltip));

        // The target div width is 100, and the tooltip width is 70, and
        // it's centered. The height of the target div is 20, and the
        // tooltip is 14px below.
        contentRect = tooltip.getBoundingClientRect();
        expect(contentRect.left).to.be.equal((100 - 70)/2);
        expect(contentRect.top).to.be.equal(20 + 14);
      });

      test('tooltip is hidden after target is blurred', functi