@Test public void whenAddFirstToSecondThenResultTwo() { Calculator calc = new Calculator(); calc.add(1d, 1d); assertThat(calc.result, is(2d)); }
public void add(double first, double second){ this.result = first + second; }
Calculator { public void add(double first, double second){ this.result = first + second; } }
Calculator { public void add(double first, double second){ this.result = first + second; }  }
Calculator { public void add(double first, double second){ this.result = first + second; }  void add(double first, double second); void substtruct(double first, double second); void div(double first, double second); void multiple(double first, double second); }
Calculator { public void add(double first, double second){ this.result = first + second; }  void add(double first, double second); void substtruct(double first, double second); void div(double first, double second); void multiple(double first, double second); public double result; }