java - 我应该期待哪个异常(exception)

有一个违反数据库唯一约束的单元测试。当我跑步时：

try {
    someDao.save(employee2);
} catch (Exception e) {
    Class clazz = e.getClass();
    System.out.println( clazz.getName());
}

e的实际类别是javax.persistence.PersistenceException。
好的，我将测试代码更新为：

exception.expect(PersistenceException.class);
someDao.save(employee2);

但是测试失败，并显示以下错误：

Expected: an instance of javax.persistence.PersistenceException
     but: <org.junit.internal.runners.model.MultipleFailureException: There were 2 errors:
  javax.persistence.PersistenceException(org.hibernate.exception.ConstraintViolationException: could not execute statement)
  org.springframework.transaction.TransactionSystemException(Could not commit JPA transaction; nested exception is javax.persistence.RollbackException: Transaction marked as rollbackOnly)> is a org.junit.internal.runners.model.MultipleFailureException
Stacktrace was: org.junit.internal.runners.model.MultipleFailureException: There were 2 errors:
  javax.persistence.PersistenceException(org.hibernate.exception.ConstraintViolationException: could not execute statement)
  org.springframework.transaction.TransactionSystemException(Could not commit JPA transaction; nested exception is javax.persistence.RollbackException: Transaction marked as rollbackOnly)

我尝试了以下所有例外，但没有帮助：

exception.expect(org.springframework.transaction.TransactionSystemException.class);
exception.expect(org.hibernate.exception.ConstraintViolationException.class);

违反数据库约束时应该期待哪个异常？

最佳答案

这不是最佳方法，但对单元测试很有用！

    try
  {
    someDao.save(employee2);
  } catch (Exception e) {
    System.out.println(e.getMessage());
  }

假设您得到一些输出，然后将其存储在错误字符串中。记下这一点并按如下所示更新您的测试用例

@Test
public void testException() {
    try {
       someDao.save(employee2);
       fail("expected an exception");
    } catch (PersistenceException ex) {
       assertEquals(Error, ex.getMessage());
    }
}