### Question:
FunctionColumnParametersHeaderMetaData extends EditablePopupHeaderMetaData<HasParametersControl, ParametersPopoverView.Presenter> { String getFormalParametersTitle() { final List<InformationItem> formalParameters = functionSupplier.get().get().getFormalParameter(); final StringBuilder sb = new StringBuilder(); sb.append("("); if (!formalParameters.isEmpty()) { sb.append(formalParameters.stream().map(ii -> ii.getName().getValue()).collect(Collectors.joining(", "))); } sb.append(")"); return sb.toString(); } FunctionColumnParametersHeaderMetaData(final Supplier<Optional<FunctionDefinition>> functionSupplier,
                                                  final TranslationService translationService,
                                                  final CellEditorControlsView.Presenter cellEditorControls,
                                                  final ParametersPopoverView.Presenter editor,
                                                  final FunctionGrid gridWidget); @Override String getColumnGroup(); @Override String getTitle(); @Override Group render(final GridHeaderColumnRenderContext context,
                        final double blockWidth,
                        final double blockHeight); @Override Optional<String> getPlaceHolder();  }### Answer:
@Test public void testGetFormalParametersTitleOneParameter() { setupFormalParameters("p0"); assertEquals("(p0)", header.getFormalParametersTitle()); }
@Test public void testGetFormalParametersTitleMultipleParameters() { setupFormalParameters("p0", "p1"); assertEquals("(p0, p1)", header.getFormalParametersTitle()); }