### Question:
ModulusOperation implements Operation { @Override public int calculate(int a, int b) { return a % b; }  @Override int calculate(int a, int b); @Override String name();  }### Answer:
@Test public void testModulus() { Operation op = new ModulusOperation(); assertThat(op.calculate(5, 2)).isEqualTo(1); assertThat(op.calculate(10, 5)).isEqualTo(0); assertThat(op.calculate(4, 2)).isEqualTo(0); }