Calculator { public Double reset() { num2 = 0.0; num1 = 0.0; mode = BiOperatorModes.normal; return NaN; }  Double calculateBi(BiOperatorModes newMode, Double num); Double calculateEqual(Double num); Double reset(); Double calculateMono(MonoOperatorModes newMode, Double num);  }
@Test void resetTest() { Calculator calculator = new Calculator(); calculator.calculateBi(Calculator.BiOperatorModes.add, 6.4); Assertions.assertEquals(8.4, calculator.calculateBi(Calculator.BiOperatorModes.add, 2.0)); Assertions.assertEquals(NaN, calculator.reset()); }