Interrupted test cases cause random failures with thread reuse

Whenever a test case is interrupted (Thread.interrupt()), the test runner thread seems to stay in interrupted state. This causes random failures later when the thread is reused for other test cases.

Expected behaviour: When the thread is reused, interrupted flag for the thread is cleaned before starting a new test case. This can be done by calling Thread.interrupted(), which returns the interrupted state, and clears the interrupted flag.

The following code should reproduce the problem, given that test1 is run before test2

import org.junit.Test;

public class ThreadTest {
  @Test
  public void test1() {
    Thread.currentThread().interrupt();
  }

  @Test
  public void test2() throws InterruptedException {
    Thread.sleep(1000);
  }
}

The problem I encountered is similar to the one described in https://www.thoughtwire.com/junit-interupt/

[ArneDeutsch]

I would support the idea to call Thread.interrupted() on each thread that is reused for more than one test case just before executing a new test case. But especially if one thread is used for more then one test class. The interrupted flag is state that leaks from one test case to others, making test cases flaky. Especially the test cases that deal with multiple threads that are notoriously hard to get right anyway.

[marcphilipp]

@joaodias14 Please upgrade to the latest version, it was fixed in 5.4.0 (see https://github.com/junit-team/junit5/issues/1688).