@BeforeAll is used to signal that the annotated method should be
executed before all tests in the current test class.
In contrast to @BeforeEach methods, @BeforeAll
methods are only executed once for a given test class.
Method Signatures
@BeforeAll methods must have a void return type and must
be static by default. Consequently, @BeforeAll methods are
not supported in @Nested test classes or as interface
default methods unless the test class is annotated with
@TestInstance(Lifecycle.PER_CLASS).
However, beginning with Java 16 @BeforeAll methods may be declared as
static in @Nested test classes, and the
Lifecycle.PER_CLASS restriction no longer applies. @BeforeAll
methods may optionally declare parameters to be resolved by
ParameterResolvers.
Using private visibility for @BeforeAll methods is
strongly discouraged and will be disallowed in a future release.
Inheritance and Execution Order
@BeforeAll methods are inherited from superclasses as long as
they are not hidden (default mode with static modifier),
overridden, or superseded (i.e., replaced based on
signature only, irrespective of Java's visibility rules). Furthermore,
@BeforeAll methods from superclasses will be executed before
@BeforeAll methods in subclasses.
Similarly, @BeforeAll methods declared in an interface are
inherited as long as they are not hidden or overridden,
and @BeforeAll methods from an interface will be executed before
@BeforeAll methods in the class that implements the interface.
JUnit Jupiter does not guarantee the execution order of multiple
@BeforeAll methods that are declared within a single test class or
test interface. While it may at times appear that these methods are invoked
in alphabetical order, they are in fact sorted using an algorithm that is
deterministic but intentionally non-obvious.
In addition, @BeforeAll methods are in no way linked to
@AfterAll methods. Consequently, there are no guarantees with regard
to their wrapping behavior. For example, given two
@BeforeAll methods createA() and createB() as well as
two @AfterAll methods destroyA() and destroyB(), the
order in which the @BeforeAll methods are executed (e.g.
createA() before createB()) does not imply any order for the
seemingly corresponding @AfterAll methods. In other words,
destroyA() might be called before or after
destroyB(). The JUnit Team therefore recommends that developers
declare at most one @BeforeAll method and at most one
@AfterAll method per test class or test interface unless there are no
dependencies between the @BeforeAll methods or between the
@AfterAll methods.
Composition
@BeforeAll may be used as a meta-annotation in order to create
a custom composed annotation that inherits the semantics of
@BeforeAll.
- Since:
- 5.0
- See Also: