在JUnit测试用例中指定执行顺序 [英] Specifying order of execution in JUnit test case
问题描述
我有一个测试用例，我添加一个实体，更新它并删除它。因此，执行顺序在这里很重要。我希望它是：
I have a test case where I add an entity, update it and delete the same. Hence, the order of execution is important here. I want it to be :
- 创建
- 更新
- 删除
奇怪的是，对于一个测试用例（15个中），JUnit按以下顺序执行：
Strangely, for just one test case ( out of 15) , JUnit executes it in the following order :
- 删除
- 更新
- 创建。
如何告诉JUnit按特定顺序执行它们？在其他情况下，JUnit完全正常（串行执行）。为什么JUnit在这种情况下表现得很奇怪？
How do I tell JUnit to execute them in a specific order ? In other cases, JUnit works totally fine ( executing serially ) . And why does JUnit behave weirdly in this one case ?
以下相关代码段：
private static Date date;
private static int entity;
static Parking p;
public ParkingTests(String name) {
super(name);
}
public void testAdd() throws Exception {
//Add code here
}
public void testUpdate() throws Exception {
//update code here
}
public void testDelete() throws Exception {
//delete code here
}
}
它变得怪异。我作为套件的一部分运行了很多测试用例。如果我只运行停车箱，则维持订单。如果我和其他人一起运行它，有时会保持，有时不会！
It gets weirder. I run a lot of test cases as part of a suite. If I run just the Parking case, the order is maintained. If I run it along with others, it is sometimes maintained, sometimes not !
推荐答案
您的情况 尴尬，因为为了保持重复工作感觉不好隔离测试（见下文） - 但请注意，大部分复制可以拉入 setUp 和 tearDown （ @Before ， @After ）方法，因此您不需要额外的代码。如果测试运行速度太慢而不能经常停止运行，那么最好在清洁测试的名义上浪费一些CPU。
Your kind of situation is awkward, as it feels bad to keep duplicating work in order to isolate the tests (see below) - but note that most of the duplication can be pulled out into setUp and tearDown (@Before, @After) methods, so you don't need much extra code. Provided that the tests are not running so slowly that you stop running them often, it's better to waste a bit of CPU in the name of clean testing.
public void testAdd() throws Exception {
// wipe database
// add something
// assert that it was added
}
public void testUpdate() throws Exception {
// wipe database
// add something
// update it
// assert that it was updated
}
public void testDelete() throws Exception {
// wipe database
// add something
// delete it
// assert that it was deleted
}
另一种方法是将所有内容都放在一个带有多个断言的测试中，但这很难理解和维护，并在测试失败时提供少量信息：
The alternative is to stick everything into one test with multiple asserts, but this is harder to understand and maintain, and gives a bit less information when a test fails:
public void testCRUD() throws Exception {
// wipe database
// add something
// assert that it was added
// update it
// assert that it was updated
// delete it
// assert that it was deleted
}
使用数据库或集合或任何类型的存储进行测试很棘手，因为一个测试可以总是通过将垃圾留在数据库/集合中来影响其他测试。即使你的测试没有明确地依赖彼此，它们仍然可能互相干扰，特别是如果其中一个失败。
Testing with databases or collections or storage of any kind is tricky because one test can always affect other tests by leaving junk behind in the database/collection. Even if your tests don't explicitly rely on one another, they may still interfere with one another, especially if one of them fails.
尽可能使用新的实例对于每个测试，或擦除数据，理想情况下尽可能简单 - 例如对于数据库而言，擦除整个表的可能性比非常特定的删除更容易成功，您可能会意外地出错。
Where possible, use a fresh instance for each test, or wipe the data, ideally in as simple a way as possible - e.g. for a database, wiping an entire table is more likely to succeed than a very specific deletion that you might accidentally get wrong.
更新：通常在测试开始时擦除数据会更好，因此一次测试运行失败不会影响下一次运行。
Update: It's usually better to wipe data at the start of the test, so one failed test run doesn't affect the next run.
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