@Test public void addTwoNumbers() { double resultAdd = mCalculator.add(1d, 1d); assertThat(resultAdd, is(equalTo(2d))); }
public double add(double firstOperand, double secondOperand) { return firstOperand + secondOperand; }
Calculator { public double add(double firstOperand, double secondOperand) { return firstOperand + secondOperand; } }
Calculator { public double add(double firstOperand, double secondOperand) { return firstOperand + secondOperand; }  }
Calculator { public double add(double firstOperand, double secondOperand) { return firstOperand + secondOperand; }  double add(double firstOperand, double secondOperand); double sub(double firstOperand, double secondOperand); double div(double firstOperand, double secondOperand); double mul(double firstOperand, double secondOperand); }
Calculator { public double add(double firstOperand, double secondOperand) { return firstOperand + secondOperand; }  double add(double firstOperand, double secondOperand); double sub(double firstOperand, double secondOperand); double div(double firstOperand, double secondOperand); double mul(double firstOperand, double secondOperand);  }