[java] JUnitTestsShouldIncludeAssert false positive with inherited @Rule field

[blerner]

Affects PMD Version: 6.9.0

Rule: JUnitTestsShouldIncludeAssertRule

Description: Thanks to bug #631, this rule properly looks for @Rule ExceptedException fields, and correctly does not complain about tests that use them. However, it only checks for such rules in the current class. One scenario that's come up in my students' code is writing an abstract test class with a bunch of concrete tests and an abstract factory method, and then several concrete test classes that instantiate the factory with one of several implementations. Additionally, they write some concrete tests in the concrete classes. Now, the @Rule isn't a declared field in the same class as the @Tests that use it, so this rule incorrectly fires again.

I think the solution is extending here to walk up the inheritance tree, so far as it's known (and here, it should be known), and check for inherited @Rule fields...

Code Sample demonstrating the issue:

import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.ExpectedException;

abstract class Shape {
  double size;

  Shape(double size) { 
    if (size < 0) {
      throw new IllegalArgumentException("negative size");
    }
    this.size = size; 
  }

  public abstract double area();
}

class Square extends Shape {
  Square(double size) {
    super(size);
  }
  
  public double area() {
    return size * size;
  }
}

class Weird extends Shape {
  Weird(double size) {
    super(size);
  }
  
  public double area() {
    throw new RuntimeException("just 'cause");
  }
}

public abstract class ShapeTester {
  protected abstract Shape factory(double size);

  @Rule
  public ExpectedException e = ExpectedException.none();

  @Test 
  public void notAProblem() {
    e.expect(IllegalArgumentException.class);
    factory(-5);
  }

  public static final class SquareTester extends ShapeTester {
    protected Shape factory(double size) {
      return new Square(size);
    }
  }

  public static final class WeirdTester extends ShapeTester {
    protected Shape factory(double size) {
      return new Weird(size);
    }

    @Test
    public void thisOneTriggersRule() {
      e.expect(RuntimeException.class);
      e.expectMessage("just 'cause");
      factory(42).area();
    }
  }
}

Running PMD through: programmatically

[adangel]

Fixed via #2899 for PMD 7.

[Sandm-HY]

Hello, so is this issue resolved now?

[jsotuyod]

Yes, PMD 7 RCs include this fix.