java - 我应该期待哪个异常(exception)

Question

有一个违反数据库唯一约束的单元测试。当我运行时:

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

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

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

但测试失败并出现以下错误:

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)

我已经尝试了以下所有异常(exception)情况，但没有帮助:

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

当违反数据库约束时，我应该期待哪个异常？

Answer 1

这不是最好的方法，但对单元测试很有效!

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

假设您得到了一些输出。让我们将其存储在Error 字符串中。记下这一点并按如下方式更新您的测试用例

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