JUnit 4 TestRule to run a test repeatedly for a specified amount of repititions

Repeat.java

import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Retention( RetentionPolicy.RUNTIME )
@Target( {
  java.lang.annotation.ElementType.METHOD
} )
public @interface Repeat {
  public abstract int times();
}

RepeatRule.java

import org.junit.rules.TestRule;
import org.junit.runner.Description;
import org.junit.runners.model.Statement;

public class RepeatRule implements TestRule {

    private static class RepeatStatement extends Statement {

    private final int times;
    private final Statement statement;

    private RepeatStatement( int times, Statement statement ) {
      this.times = times;
      this.statement = statement;
    }

    @Override
    public void evaluate() throws Throwable {
      for( int i = 0; i < times; i++ ) {
        statement.evaluate();
      }
    }
  }

  @Override
  public Statement apply( Statement statement, Description description ) {
    Statement result = statement;
    Repeat repeat = description.getAnnotation( Repeat.class );
    if( repeat != null ) {
      int times = repeat.times();
      result = new RepeatStatement( times, statement );
    }
    return result;
  }
}

hi @fappel
i liked this JUnit rule. i am wondering what is the reasoning of making times method of Repeat annotation abstract? i see no use of it AFAIK.

I'd love to see this in the official JUnit project. What about creating a pull request out of this?

+1

+1

How many times will Before and After methods be called?

Thanks for sharing @fappel. I've documented and tidied it up as well as incorporated @bazi's comment.

See my fork https://gist.github.com/coolersport/b0c26c601c7739d1cbf5f6ded8210bae

Nice work 👍 thank you @fappel.
It could be interesting to add a random wait option between executions with a default value set to 0 ms.

Here is a proposal below.

https://gist.github.com/cbismuth/5f5315ccd8a8f4b1e4a129c40ee5edd3