helper.specificAutocompleter = new StubAutocompleter();
MockAutocompleter autocompleter = helper.setup(path, "a", 0, 1, false);
AutocompleteController controller = autocompleter.getController();
assertNotNull(controller);
autocompleter.requestAutocomplete(controller, null);
autocompleter.reallyFinishAutocompletion(helper.popup.proposals.select(0));
assertEquals("ab", helper.editor.getDocument().asText());
// check that the caret is in the right place
assertEquals(2, helper.editor.getSelection().getCursorColumn());
assertNotNull(autocompleter.getController());