for (TwoArg.Action first : TwoArg.Action.values()) {
      for (TwoArg.Action second : TwoArg.Action.values()) {
        TwoArg bar = new TwoArg(first, second);
        verifyBarPass(method, bar); // All args nullable:  anything goes!
      }
    }
  }

  /*
   * This next part consists of several sample classes that provide
   * demonstrations of conditions that cause NullPointerTester
   * to succeed/fail.
   */

            // and only for plain old jars. Not war files, not ear files, not anything else.
            return determineBuildOutputDirectoryForArtifact(project, artifact);
        }

        // The fall-through indicates that the artifact cannot be found;
        // for instance if package produced nothing or classifier problems.
        return null;
    }

   * source Iterable, unless that Iterator is unmodifiable.
   */
  protected abstract I newTargetIterator();

  /**
   * Override this to verify anything after running a list of Stimuli.
   *
   * <p>For example, verify that calls to remove() actually removed the correct elements.
   *
   * @param elements the expected elements passed to the constructor, as mutated by {@code

Available JDKs on your machine are automatically detected and wired for the various compile and test tasks.
Some tests require multiple JDKs to be installed on your computer, be aware of this if you make changes related to anything toolchains related.

If you want to explicitly run tests with a different Java version, you need to specify `-PtestJavaVersion=#` with the major version of the JDK you want the tests to run with (e.g. `-PtestJavaVersion=14`).

   * source Iterable, unless that Iterator is unmodifiable.
   */
  protected abstract I newTargetIterator();

  /**
   * Override this to verify anything after running a list of Stimuli.
   *
   * <p>For example, verify that calls to remove() actually removed the correct elements.
   *
   * @param elements the expected elements passed to the constructor, as mutated by {@code

   * Returns an {@code ImmutableList} containing the same elements, in the same order, as this
   * collection.
   *
   * <p><b>Performance note:</b> in most cases this method can return quickly without actually
   * copying anything. The exact circumstances under which the copy is performed are undefined and
   * subject to change.
   *
   * @since 2.0
   */
  public ImmutableList<E> asList() {
    switch (size()) {
      case 0:

   * Returns an {@code ImmutableList} containing the same elements, in the same order, as this
   * collection.
   *
   * <p><b>Performance note:</b> in most cases this method can return quickly without actually
   * copying anything. The exact circumstances under which the copy is performed are undefined and
   * subject to change.
   *
   * @since 2.0
   */
  public ImmutableList<E> asList() {

      // Fine: If it doesn't exist, then there's no chance that we're going to be asked to test it.
    }

    /*
     * These methods "should" call checkNotNull. However, I'm wary of accidentally introducing
     * anything that might slow down execution on such a hot path. Given that the methods are only
     * package-private, I feel OK with just not testing them for NPE.
     *

      // Fine: If it doesn't exist, then there's no chance that we're going to be asked to test it.
    }

    /*
     * These methods "should" call checkNotNull. However, I'm wary of accidentally introducing
     * anything that might slow down execution on such a hot path. Given that the methods are only
     * package-private, I feel OK with just not testing them for NPE.
     *

    SUCCESS,

    /** The method returned false. */
    FAILURE,

    /** The method threw an InterruptedException. */
    INTERRUPT,

    /** The method did not return or throw anything. */
    HANG;

    @Override
    public String toString() {
      return CaseFormat.UPPER_UNDERSCORE.to(CaseFormat.UPPER_CAMEL, name());
    }
  }