GridLayout extends LayoutBase { public void setNumColumns(int numColumns) { this.numColumns.set(numColumns); }  @Override void addChild(Component component, double x, double y); void addChild(Component component, GridPoint point); @Override Component addComponent(ComponentModel model); @Override Pane getView(); @Override List<Group> getSettings(); @Override String getName(); ImmutableList<ChildContainer> getContainers(); int getNumColumns(); IntegerProperty numColumnsProperty(); void setNumColumns(int numColumns); int getNumRows(); IntegerProperty numRowsProperty(); void setNumRows(int numRows);  }
@Test public void testReduceColumnCount() { FxUtils.runOnFxThread(() -> layout.setNumColumns(2)); waitForFxEvents(); assertEquals(6, getPlaceholderCount(), "Removing a column should reduce the number of placeholders from 9 to 6"); }
@Test public void testIncreaseColumnCount() { FxUtils.runOnFxThread(() -> layout.setNumColumns(4)); waitForFxEvents(); assertEquals(12, getPlaceholderCount(), "Adding a column should increase the number of placeholders from 9 to 12"); }