### Question:
MapRecord implements MutableRecord { @Override public boolean removeField(String field) { if (!records.containsKey(field)) { return false; } records.remove(field); return true; } MapRecord(); @Override List<Value> getValues(String field); @Override MutableRecord makeMutable(); @Override boolean isMutable(); @Override boolean addField(String field, List<Value> values); @Override boolean addValue(String field, Value value); @Override boolean removeField(String field); @Override boolean removeValue(String field, Value value); @Override boolean updateField(String field, List<Value> value); @Override boolean updateValue(String field, Value old_value, Value new_value); @Override boolean hasField(String field); @Override Set<String> getFields();  }### Answer:
@Test public void testRemoveField() { assertFalse(rec.removeField("test")); rec.addField("test", val); assertTrue(rec.removeField("test")); assertFalse(rec.removeField("test")); }