Consider passing the following values to assertEquals:
0.0, 0.0, 0.0 (false failure)
1.0, 2.0, 0.1 (false pass)
-1.0, -2.0, 0.1 (false pass)

Assert super-source:

  static public void assertEquals(String str, float obj1, float obj2,
float delta) {
    if (obj1 - obj2 < delta || obj2 - obj1 < delta) {
      return;
    } else {
      fail(str + " expected=" + obj1 + " actual=" + obj2 + " delta=" + delta);
    }
  }

I suggested a better implementation in the linked post.

I'm incorporating your test case into an existing on.  Your fix looks
good except I think that should be a "<= delta" instead of a "< delta".

This is the code I think I'm going to commit:

  static public void assertEquals(String str, double obj1, double obj2,
      double delta) {
    if (obj1 == obj2) {
      return;
    } else if (Math.abs(obj1 - obj2) <= delta) {
      return;
    } else {
      fail(str + " expected=" + obj1 + " actual=" + obj2 + " delta=" +
delta);
    }
  }

  static public void assertEquals(String str, float obj1, float obj2,
      float delta) {
    if (obj1 == obj2) {
      return;
    } else if (Math.abs(obj1 - obj2) <= delta) {
      return;
    } else {
      fail(str + " expected=" + obj1 + " actual=" + obj2 + " delta=" +
delta);
    }
  }