JUnit @BeforeClass non-static work around for Spring Boot application

Question

JUnit's @BeforeClass annotation must be declared static if you want it to run once before all the @Test methods. However, this cannot be used with dependency injection.

I want to clean up a database that I @Autowire with Spring Boot, once before I run my JUnit tests. I cannot @Autowire static fields so I need to think of a work around. Any ideas?

score 52 · Accepted Answer · edited Jul 25 '20 at 15:28

52

Just use @Before (instead of @BeforeClass) (or Spring's @BeforeTransaction (depending on how you initialize the database)). This annotation must been attached to an nonstatic public method.

Of course: @Before run before EACH test case method (not like @BeforeClass that runs only once.) But if you want to run it exactly once, then use an static marker field.

private static boolean initialized = false;
...
@Before
public void initializeDB() { 
   if (!initialized) {
       ... //your db initialization
       initialized = true;
   }
}
---

edited Jul 25 '20 at 15:28

Steve Chambers

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answered Oct 05 '15 at 19:37

Ralph

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that's what i do when i have to use JUnit. But I prefer to use TestNG which has all annotations available on non-static methods : in your case with TestNG, @BeforeClass would be defined on a non-static methods, and is would be executed once before all the test methods inside that class. – Gauthier Peel Aug 29 '16 at 13:52
Is there a workaround for `@AfterClass`? I want to remove all data inserted in the database because I'm using an external database. – LunaticJape May 14 '19 at 15:00
2

@LunaticJape: my workarround is to use the `@After` Method to pass an instance (`@Autowired` field value) to an static field, and then use this field in the `@AfterClass` Method. – Ralph May 19 '19 at 06:23
@LunaticJape see https://stackoverflow.com/questions/37083647/junit-afterclass-non-static – AsfK Jul 16 '20 at 17:20

score 5 · Answer 2 · answered Sep 19 '19 at 08:45

For JUnit5: Test Execution Order and @TestInstance(Lifecycle.PER_CLASS)

Kotlin example:

@ExtendWith(SpringExtension::class)
@TestInstance(PER_CLASS)
class BeforeInstanceTests {

    private var initialized: String = ""
    private val callList: MutableList<String> = ArrayList()

    @BeforeAll
    fun beforeAllNonStatic() {
        initialized = "initialized"
        assertEquals(0, callList.size)
    }

    @Test
    fun test1() {
        assertEquals("initialized", initialized)
        callList.add("test1")
    }

    @Test
    fun test2() {
        assertEquals("initialized", initialized)
        callList.add("test2")
    }

    @Test
    fun test3() {
        assertEquals("initialized", initialized)
        callList.add("test3")
    }

    @AfterAll
    fun afterAllNonStatic() {
        assertEquals("initialized", initialized)
        assertEquals(3, callList.size)
        assertTrue(callList.contains("test1"))
        assertTrue(callList.contains("test2"))
        assertTrue(callList.contains("test3"))

        callList.clear()
        initialized = ""
    }
}

score 1 · Answer 3 · answered Oct 05 '15 at 16:09

1

Have a look at the DBUnit library - it's designed to perform the actions you're describing. It can create & tear down database instances and provides you with simple ways to do this.

answered Oct 05 '15 at 16:09

TrueDub

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score -1 · Answer 4 · answered Jul 24 '18 at 05:16

-1

Though accepted answer is clever, seems hacky. Have you tried using a normal Constructor?

public class MyJUnitTest {

    public MyJUnitTest() {
       // code for initializeDB
    }

    // Tests

}

answered Jul 24 '18 at 05:16

Arun Avanathan

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This won't work. JUnit creates a new instance of the testing class for each \@Test. So using the constructor is effectively the same as \@Before, not \@BeforeClass – Azianese Dec 04 '19 at 04:09

score -2 · Answer 5 · answered Sep 18 '17 at 08:42

-2

Try this solution: https://stackoverflow.com/a/46274919/907576 :

with @BeforeAllMethods/@AfterAllMethods annotations you could execute any method in Test class in an instance context, where all injected values are available.

answered Sep 18 '17 at 08:42

radistao

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1

This doesn't work because these annotations don't exist in a spring boot application. The question clearly says Spring boot application! Don't give advice that doesn't work. – Martijn Hiemstra Dec 24 '18 at 09:29
In the mentioned solution there are references to the dependencies with the annotations. Because stackoverflow doesn't allow duplicate answers i just mentioned the references to another more descriptive answer. – radistao Dec 24 '18 at 09:53

JUnit @BeforeClass non-static work around for Spring Boot application

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