@Test(dataProvider = "randomValidGroupGenerator")
	public void modifySomeGroup(GroupData groupData) {
		app.getNavigationHelper().openMainPage();
		app.getNavigationHelper().movingToGroups();
	    
	    // save old state
	    List<GroupData> oldList = app.getGroupHelper().getGroups();

	    Random rn = new Random();
	    int index = rn.nextInt(oldList.size() - 1);
	    
	    //actions
	    //Initiation of the [index + 1] group modification
		app.getGroupHelper()
			.initGroupModification(index)
			.fillGroupInformation(groupData)
			.submitGroupModification()
			.returnToGroupPage();
	    
	    // save new state
	    List<GroupData> newList = app.getGroupHelper().getGroups();
	    
	    //compare states
	    oldList.remove(index);
	    oldList.add(groupData);
	    Collections.sort(oldList);
	    assertEquals(newList, oldList);
	}