package org.junit.rules;
import org.junit.Rule;
import org.junit.runners.model.FrameworkMethod;
import org.junit.runners.model.Statement;
/**
* A MethodRule is an alteration in how a test method is run and reported.
* Multiple {@link MethodRule}s can be applied to a test method. The
* {@link Statement} that executes the method is passed to each annotated
* {@link Rule} in turn, and each may return a substitute or modified
* {@link Statement}, which is passed to the next {@link Rule}, if any. For
* examples of how this can be useful, see these provided MethodRules,
* or write your own:
*
* <ul>
* <li>{@link ErrorCollector}: collect multiple errors in one test method</li>
* <li>{@link ExpectedException}: make flexible assertions about thrown exceptions</li>
* <li>{@link ExternalResource}: start and stop a server, for example</li>
* <li>{@link TemporaryFolder}: create fresh files, and delete after test</li>
* <li>{@link TestName}: remember the test name for use during the method</li>
* <li>{@link TestWatchman}: add logic at events during method execution</li>
* <li>{@link Timeout}: cause test to fail after a set time</li>
* <li>{@link Verifier}: fail test if object state ends up incorrect</li>
* </ul>
*
* Note that {@link MethodRule} has been replaced by {@link TestRule},
* which has the added benefit of supporting class rules.
*
* @since 4.7
*/
public interface MethodRule {
/**
* Modifies the method-running {@link Statement} to implement an additional
* test-running rule.
*
* @param base The {@link Statement} to be modified
* @param method The method to be run
* @param target The object on with the method will be run.
* @return a new statement, which may be the same as {@code base},
* a wrapper around {@code base}, or a completely new Statement.
*/
Statement apply(Statement base, FrameworkMethod method, Object target);
}