DblAddition implements FieldAddition<Double> { @Override public Double add(final Double operand, final Double second) { return operand + second; }  @Override Double add(final Double operand, final Double second); @Override Double neutral(); @Override Double inverse(final Double elt);  }
@Test public void calculatesAddition() { final double first = Math.random(); final double second = Math.random(); MatcherAssert.assertThat( new DblAddition().add(first, second), Matchers.equalTo(first + second) ); }