private double DoCalculation()
{
switch (calculation)
{
case CalculationType.addition:
addition.leftOperand = firstNumber.Evaluate();
addition.rightOperand = secondNumber.Evaluate();
return(addition.Evaluate());
case CalculationType.subtraction:
subtraction.leftOperand = firstNumber.Evaluate();
subtraction.rightOperand = secondNumber.Evaluate();
return(subtraction.Evaluate());
case CalculationType.multiplication:
multiplication.leftOperand = firstNumber.Evaluate();
multiplication.rightOperand = secondNumber.Evaluate();
return(multiplication.Evaluate());
case CalculationType.division:
division.leftOperand = firstNumber.Evaluate();
division.rightOperand = secondNumber.Evaluate();
return(division.Evaluate());
default:
return(0);
}
}
public void EvaluateWithTwoNormalOperands()
{
var left = new Expression { Value = 1 };
var right = new Expression { Value = 2 };
var expression = new SubtractionExpression(left, right);
Assert.AreEqual(-1, expression.Evaluate());
}
public void EvaluateWithTwoNormalOperands()
{
var left = new ConstantExpression(1);
var right = new ConstantExpression(2);
var expression = new SubtractionExpression(left, right);
Assert.AreEqual(-1, expression.Evaluate());
}
public void EvaluateWithOneSubtractionExpression()
{
var left = new Expression { Value = 1 };
var leftTwo = new Expression { Value = 2 };
var rightTwo = new Expression { Value = 3 };
var right = new SubtractionExpression(leftTwo, rightTwo);
var expression = new SubtractionExpression(left, right);
Assert.AreEqual(2, expression.Evaluate());
}
public void EvaluateWithOneSubtractionExpression()
{
var left = new ConstantExpression(1);
var leftTwo = new ConstantExpression(2);
var rightTwo = new ConstantExpression(3);
var right = new SubtractionExpression(leftTwo, rightTwo);
var expression = new SubtractionExpression(left, right);
Assert.AreEqual(2, expression.Evaluate());
}
