### Question:
CoordinateEd25519 extends Coordinate { @Override public final Coordinate add(Coordinate val) { BigInteger integer = val.getInteger(); return new CoordinateEd25519(value.add(integer)); } CoordinateEd25519(BigInteger integer); @Override final Coordinate add(Coordinate val); @Override final Coordinate divide(Coordinate val); @Override final Coordinate multiply(Coordinate val); @Override final Coordinate subtract(Coordinate val); @Override final Coordinate mod(); @Override final Coordinate inverse(); @Override Coordinate powerMod(BigInteger exponent); @Override Coordinate negate(); @Override EncodedCoordinate encode(); static final CoordinateEd25519 ONE; }### Answer:
@Test public void success_AddCoordinate() { Coordinate coordinate1 = new CoordinateEd25519(new BigInteger("1")); Coordinate coordinate2 = new CoordinateEd25519(new BigInteger("2")); Coordinate result = coordinate1.add(coordinate2); assertEquals(result.getInteger(), new BigInteger("3")); }