JUnit 5 assertTimeout Example

JUnit 5 Tutorial

In this article, we will learn about assertTimeout() static method which belongs to JUnit 5 org.junit.jupiter.api.Assertions Class. Note that in JUnit 5 all JUnit 4 assertion methods are moved to org.junit.jupiter.api.Assertions class.

There are many overloaded version of assertTimeout() methods present in org.junit.jupiter.api.Assertions class.

Let me list out tools and technologies that I have used to develop JUnit 5 assertTimeout Example.

Tools and Technologies Used

Eclipse photon (only this eclipse version supports JUnit 5)
Maven
JUnit 5
JDK 8 or later

assertTimeout(Duration timeout, ThrowingSupplier supplier) method asserts that execution of the supplied supplier completes before the given timeout is exceeded.

assertTimeout Method Example

package com.javaguides.junit5.assertions;

import static org.junit.Assert.assertEquals;

import static java.time.Duration.ofMillis;
import static java.time.Duration.ofMinutes;
import static org.junit.jupiter.api.Assertions.assertTimeout;

import org.junit.jupiter.api.Test;

/**
 * JUnit5AssertTimeOutExample
 * @author javaguides.net
 *
 */
public class JUnit5AssertTimeOutExample {

 private static String greeting() {
  return "Hello, World!";
 }

 @Test
 void timeoutNotExceeded() {
  // The following assertion succeeds.
  assertTimeout(ofMinutes(2), () -> {
   // Perform task that takes less than 2 minutes.
  });
 }

 @Test
 void timeoutNotExceededWithResult() {
  // The following assertion succeeds, and returns the supplied object.
  String actualResult = assertTimeout(ofMinutes(2), () -> {
   return "a result";
  });
  assertEquals("a result", actualResult);
 }

 @Test
 void timeoutNotExceededWithMethod() {
  // The following assertion invokes a method reference and returns an object.
  String actualGreeting = assertTimeout(ofMinutes(2), JUnit5AssertTimeOutExample::greeting);
  assertEquals("Hello, World!", actualGreeting);
 }

 @Test
 void timeoutExceeded() {
  // The following assertion fails with an error message similar to:
  // execution exceeded timeout of 10 ms by 91 ms
  assertTimeout(ofMillis(10), () -> {
   // Simulate task that takes more than 10 ms.
   Thread.sleep(100);
  });
 }
}