Package org.junit.rules
Interface TestRule
- All Known Implementing Classes:
DisableOnDebug
,ErrorCollector
,ExpectedException
,ExternalResource
,RuleChain
,Stopwatch
,Stopwatch.InternalWatcher
,TemporaryFolder
,TestName
,TestWatcher
,Timeout
,Verifier
public interface TestRule
A TestRule is an alteration in how a test method, or set of test methods,
is run and reported. A
TestRule
may add additional checks that cause
a test that would otherwise fail to pass, or it may perform necessary setup or
cleanup for tests, or it may observe test execution to report it elsewhere.
TestRule
s can do everything that could be done previously with
methods annotated with Before
,
After
, BeforeClass
, or
AfterClass
, but they are more powerful, and more easily
shared
between projects and classes.
The default JUnit test runners for suites and
individual test cases recognize TestRule
s introduced in two different
ways. Rule
annotates method-level
TestRule
s, and ClassRule
annotates class-level TestRule
s. See Javadoc for those annotations
for more information.
Multiple TestRule
s can be applied to a test or suite execution. The
Statement
that executes the method or suite is passed to each annotated
Rule
in turn, and each may return a substitute or modified
Statement
, which is passed to the next Rule
, if any. For
examples of how this can be useful, see these provided TestRules,
or write your own:
ErrorCollector
: collect multiple errors in one test methodExpectedException
: make flexible assertions about thrown exceptionsExternalResource
: start and stop a server, for exampleTemporaryFolder
: create fresh files, and delete after testTestName
: remember the test name for use during the methodTestWatcher
: add logic at events during method executionTimeout
: cause test to fail after a set timeVerifier
: fail test if object state ends up incorrect
- Since:
- 4.9
-
Method Summary
Modifier and TypeMethodDescriptionapply
(Statement base, Description description) Modifies the method-runningStatement
to implement this test-running rule.
-
Method Details
-
apply
Modifies the method-runningStatement
to implement this test-running rule.- Parameters:
base
- TheStatement
to be modifieddescription
- ADescription
of the test implemented inbase
- Returns:
- a new statement, which may be the same as
base
, a wrapper aroundbase
, or a completely new Statement.
-