package org.junit;
import org.junit.function.ThrowingRunnable;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
* The <code>Test</code> annotation tells JUnit that the <code>public void</code> method
* to which it is attached can be run as a test case. To run the method,
* JUnit first constructs a fresh instance of the class then invokes the
* annotated method. Any exceptions thrown by the test will be reported
* by JUnit as a failure. If no exceptions are thrown, the test is assumed
* to have succeeded.
* <p>
* A simple test looks like this:
* <pre>
* public class Example {
* <b>@Test</b>
* public void method() {
* org.junit.Assert.assertTrue( new ArrayList().isEmpty() );
* }
* }
* </pre>
* <p>
* The <code>Test</code> annotation supports two optional parameters for
* exception testing and for limiting test execution time.
*
* <h3>Exception Testing</h3>
* <p>
* The parameter <code>expected</code> declares that a test method should throw
* an exception. If it doesn't throw an exception or if it throws a different exception
* than the one declared, the test fails. For example, the following test succeeds:
* <pre>
* @Test(<b>expected=IndexOutOfBoundsException.class</b>)
* public void outOfBounds() {
* new ArrayList<Object>().get(1);
* }
* </pre>
*
* Using the parameter <code>expected</code> for exception testing comes with
* some limitations: only the exception's type can be checked and it is not
* possible to precisely specify the code that throws the exception. Therefore
* JUnit 4 has improved its support for exception testing with
* {@link Assert#assertThrows(Class, ThrowingRunnable)} and the
* {@link org.junit.rules.ExpectedException ExpectedException} rule.
* With <code>assertThrows</code> the code that throws the exception can be
* precisely specified. If the exception's message or one of its properties
* should be verified, the <code>ExpectedException</code> rule can be used. Further
* information about exception testing can be found at the
* <a href="https://github.com/junit-team/junit4/wiki/Exception-testing">JUnit Wiki</a>.
*
* <h3>Timeout</h3>
* <p>
* The parameter <code>timeout</code> causes a test to fail if it takes
* longer than a specified amount of clock time (measured in milliseconds). The following test fails:
* <pre>
* @Test(<b>timeout=100</b>)
* public void infinity() {
* while(true);
* }
* </pre>
* <b>Warning</b>: while <code>timeout</code> is useful to catch and terminate
* infinite loops, it should <em>not</em> be considered deterministic. The
* following test may or may not fail depending on how the operating system
* schedules threads:
* <pre>
* @Test(<b>timeout=100</b>)
* public void sleep100() {
* Thread.sleep(100);
* }
* </pre>
* <b>THREAD SAFETY WARNING:</b> Test methods with a timeout parameter are run in a thread other than the
* thread which runs the fixture's @Before and @After methods. This may yield different behavior for
* code that is not thread safe when compared to the same test method without a timeout parameter.
* <b>Consider using the {@link org.junit.rules.Timeout} rule instead</b>, which ensures a test method is run on the
* same thread as the fixture's @Before and @After methods.
*
* @since 4.0
*/
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.METHOD})
public @interface Test {
/**
* Default empty exception.
*/
static class None extends Throwable {
private static final long serialVersionUID = 1L;
private None() {
}
}
/**
* Optionally specify <code>expected</code>, a Throwable, to cause a test method to succeed if
* and only if an exception of the specified class is thrown by the method. If the Throwable's
* message or one of its properties should be verified, the
* {@link org.junit.rules.ExpectedException ExpectedException} rule can be used instead.
*/
Class<? extends Throwable> expected() default None.class;
/**
* Optionally specify <code>timeout</code> in milliseconds to cause a test method to fail if it
* takes longer than that number of milliseconds.
* <p>
* <b>THREAD SAFETY WARNING:</b> Test methods with a timeout parameter are run in a thread other than the
* thread which runs the fixture's @Before and @After methods. This may yield different behavior for
* code that is not thread safe when compared to the same test method without a timeout parameter.
* <b>Consider using the {@link org.junit.rules.Timeout} rule instead</b>, which ensures a test method is run on the
* same thread as the fixture's @Before and @After methods.
* </p>
*/
long timeout() default 0L;
}