### Question:
SchemaUpdate implements UpdateSchema { @Override public Schema apply() { return applyChanges(schema, deletes, updates, adds, moves); } SchemaUpdate(TableOperations ops);   SchemaUpdate(Schema schema, int lastColumnId); @Override SchemaUpdate allowIncompatibleChanges(); @Override UpdateSchema addColumn(String name, Type type, String doc); @Override UpdateSchema addColumn(String parent, String name, Type type, String doc); @Override UpdateSchema addRequiredColumn(String name, Type type, String doc); @Override UpdateSchema addRequiredColumn(String parent, String name, Type type, String doc); @Override UpdateSchema deleteColumn(String name); @Override UpdateSchema renameColumn(String name, String newName); @Override UpdateSchema requireColumn(String name); @Override UpdateSchema makeColumnOptional(String name); @Override UpdateSchema updateColumn(String name, Type.PrimitiveType newType); @Override UpdateSchema updateColumnDoc(String name, String doc); @Override UpdateSchema moveFirst(String name); @Override UpdateSchema moveBefore(String name, String beforeName); @Override UpdateSchema moveAfter(String name, String afterName); UpdateSchema updateSchema(Schema newSchema); @Override Schema apply(); @Override void commit();  }### Answer:
@Test public void testNoChanges() { Schema identical = new SchemaUpdate(SCHEMA, SCHEMA_LAST_COLUMN_ID).apply(); Assert.assertEquals("Should not include any changes", SCHEMA.asStruct(), identical.asStruct()); }