CODEWITHSUNDEEP
javamavenintellij-ideaintegration-testingmaven-plugin
user3914823
user3914823

Reputation: 11

Integration tests randomly fail or throw error when run by maven

I am running a suite of integration tests using maven and about 10% of the tests would fail or throw an error. However, when I start the server and run the individual failed tests manually from my IDE(intellij idea), they all pass with no problem. What could be the cause of this issue?

Upvotes: 1

Views: 3541

Answers (1)

Javaru
Javaru

Reputation: 31936

This is almost always caused by the unit tests running in an inconsistent order, or a race condition between two tests running in parallel via forked tests. If Test #1 finishes first, it passes. But if Test #2 finishes first, it leaves a test resource, such as a test database, in an alternate state causing Test #1 to fail. It is very common with database tests, esepecially when one or more alter the database. Even in IDEA, you may find all the tests in the com.example.FooTest class always pass when you run that class. But if you run all the tests in the com.example package or all tests in the project, sometimes (or even always) a test in FooTest fails.

The fix is to ensure your tests are always guaranteed a consistent state when run. (That is a guiding principle for good unit tests.) You need to pay attention to test setup and tear-down via the @Before, @BeforeClass, @After, and @AfterClass annotations (or TestNG equivalents). I recommend Googling database unit testing best practices. For database tests, running tests in a Transaction can prevent these type of issues. That way the database is rolled back to its starting state whether the test passes or fails. Spring has some great support for JDBC dtaabase tests. (Even if your project is not a Spring project, the classes can be very useful.) Read section 11.2.2 Unit Testing support Classes and take a look at the AbstractTransactionalJUnit4SpringContextTests / AbstractTransactionalTestNGSpringContextTests classes and the @TransactionConfiguration annotation (this latter one being from running Spring Contexts). There are also other Database testing tools out there such as DbUnit.

Upvotes: 2

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