org.junit.rules
Class Stopwatch

java.lang.Object
  org.junit.rules.Stopwatch

All Implemented Interfaces:

TestRule

public class Stopwatch
   

    extends 
    Object
   
   

    implements 
    TestRule
   

The Stopwatch Rule notifies one of its own protected methods of the time spent by a test.

Override them to get the time in nanoseconds. For example, this class will keep logging the time spent by each passed, failed, skipped, and finished test:

 public static class StopwatchTest {
     private static final Logger logger = Logger.getLogger("");

     private static void logInfo(Description description, String status, long nanos) {
         String testName = description.getMethodName();
         logger.info(String.format("Test %s %s, spent %d microseconds",
                                   testName, status, TimeUnit.NANOSECONDS.toMicros(nanos)));
     }

     @Rule
     public Stopwatch stopwatch = new Stopwatch() {
         @Override
         protected void succeeded(long nanos, Description description) {
             logInfo(description, "succeeded", nanos);
         }

         @Override
         protected void failed(long nanos, Throwable e, Description description) {
             logInfo(description, "failed", nanos);
         }

         @Override
         protected void skipped(long nanos, AssumptionViolatedException e, Description description) {
             logInfo(description, "skipped", nanos);
         }

         @Override
         protected void finished(long nanos, Description description) {
             logInfo(description, "finished", nanos);
         }
     };

     @Test
     public void succeeds() {
     }

     @Test
     public void fails() {
         fail();
     }

     @Test
     public void skips() {
         assumeTrue(false);
     }
 }
 

An example to assert runtime:

 @Test
 public void performanceTest() throws InterruptedException {
     long delta = 30;
     Thread.sleep(300L);
     assertEquals(300d, stopwatch.runtime(MILLISECONDS), delta);
     Thread.sleep(500L);
     assertEquals(800d, stopwatch.runtime(MILLISECONDS), delta);
 }
 

Since:

4.12

     

Stopwatch

public Stopwatch()

runtime

public long runtime(TimeUnit unit)

Gets the runtime for the test.

Parameters:

unit - time unit for returned runtime

Returns:

runtime measured during the test

succeeded

protected void succeeded(long nanos,
                         Description description)

Invoked when a test succeeds

failed

protected void failed(long nanos,
                      Throwable e,
                      Description description)

Invoked when a test fails

skipped

protected void skipped(long nanos,
                       AssumptionViolatedException e,
                       Description description)

Invoked when a test is skipped due to a failed assumption.

finished

protected void finished(long nanos,
                        Description description)

Invoked when a test method finishes (whether passing or failing)

apply

public final Statement apply(Statement base,
                             Description description)

Description copied from interface: TestRule

Modifies the method-running Statement to implement this test-running rule.

Specified by:

apply in interface TestRule

Parameters:

base - The Statement to be modified

description - A Description of the test implemented in base

Returns:

a new statement, which may be the same as base, a wrapper around base, or a completely new Statement.

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