### Question:
CustomColumnSetExtractor implements ColumnExtractor { @Override public void extract(String prefix) { for (Property<?> property : columns) { if (isFullObjectProp(property)) { extractFullObject(prefix, property); } else if(isEmbeddedProp(property)) { extractEmbeddedObject(prefix, property); } else { extractSimpleProperty(property); } } } CustomColumnSetExtractor(TranslatorContext context, Collection<Property<?>> columns); @Override void extract(String prefix);  }### Answer:
@Test public void testExtractWithoutPrefix() { DbEntity mockDbEntity = createMockDbEntity("mock"); TranslatableQueryWrapper wrapper = new MockQueryWrapperBuilder() .withNeedsResultSetMapping(true) .withMetaData(new MockQueryMetadataBuilder() .withDbEntity(mockDbEntity) .build()) .build(); TranslatorContext context = new MockTranslatorContext(wrapper); DataMap dataMap = new DataMap(); dataMap.addDbEntity(mockDbEntity); ObjEntity entity = new ObjEntity(); entity.setName("mock"); entity.setDataMap(dataMap); entity.setDbEntity(mockDbEntity); ObjAttribute attribute = new ObjAttribute(); attribute.setName("not_name"); attribute.setDbAttributePath("name"); attribute.setType("my.type"); entity.addAttribute(attribute); dataMap.addObjEntity(entity); EntityResolver resolver = new EntityResolver(); resolver.addDataMap(dataMap); BaseProperty<?> property0 = PropertyFactory.createBase(ExpressionFactory.dbPathExp("name"), String.class); Collection<Property<?>> properties = Collections.singleton(property0); CustomColumnSetExtractor extractor = new CustomColumnSetExtractor(context, properties); extractor.extract(); assertEquals(1, context.getResultNodeList().size()); ResultNodeDescriptor descriptor0 = context.getResultNodeList().get(0); assertSame(property0, descriptor0.getProperty()); assertNotNull(descriptor0.getNode()); assertThat(descriptor0.getNode(), instanceOf(ColumnNode.class)); assertFalse(descriptor0.isAggregate()); assertTrue(descriptor0.isInDataRow()); assertNotNull(descriptor0.getDbAttribute()); assertNull(descriptor0.getDataRowKey()); assertEquals(Types.VARBINARY, descriptor0.getJdbcType()); assertEquals("java.lang.String", descriptor0.getJavaType()); }