public void CanAddAndSubtract()
{
var engine = new Engine();
Assert.AreEqual(0, engine.Value);
engine.Digit(1);
Assert.AreEqual(1, engine.Value);
engine.Plus();
Assert.AreEqual(1, engine.Value);
engine.Digit(2);
Assert.AreEqual(2, engine.Value);
engine.Plus();
Assert.AreEqual(3, engine.Value);
engine.Digit(3);
Assert.AreEqual(3, engine.Value);
engine.Minus();
Assert.AreEqual(6, engine.Value);
engine.Digit(4);
Assert.AreEqual(4, engine.Value);
engine.Minus();
Assert.AreEqual(2, engine.Value);
engine.Digit(5);
Assert.AreEqual(5, engine.Value);
engine.Equals();
Assert.AreEqual(-3, engine.Value);
}
public void CanSubtract()
{
var engine = new Engine();
engine.Digit(1);
engine.Minus();
engine.Digit(2);
engine.Equals();
Assert.AreEqual(-1, engine.Value);
}
public void CanPlusAfterNegate()
{
var engine = new Engine();
engine.Minus();
engine.Plus();
engine.Digit(5);
engine.Minus();
engine.Digit(3);
engine.Equals();
Assert.AreEqual(2, engine.Value);
}
public void CanNegate()
{
var engine = new Engine();
engine.Minus();
engine.Digit(1);
Assert.AreEqual(-1, engine.Value);
}
public void CanEnterNegativeMultiDigitNumbers()
{
var engine = new Engine();
engine.Minus();
Assert.AreEqual(0, engine.Value);
engine.Digit(1);
Assert.AreEqual(-1, engine.Value);
engine.Digit(2);
Assert.AreEqual(-12, engine.Value);
engine.Digit(3);
Assert.AreEqual(-123, engine.Value);
engine.Plus();
Assert.AreEqual(-123, engine.Value);
engine.Minus();
Assert.AreEqual(-123, engine.Value);
engine.Digit(4);
Assert.AreEqual(-4, engine.Value);
engine.Digit(5);
Assert.AreEqual(-45, engine.Value);
engine.Digit(6);
Assert.AreEqual(-456, engine.Value);
engine.Equals();
Assert.AreEqual(-579, engine.Value);
}
public void CanEnterNegativeDecimals()
{
var engine = new Engine();
engine.Minus();
engine.Point();
engine.Digit(1);
Assert.AreEqual(-0.1, engine.Value);
engine.Digit(2);
Assert.AreEqual(-0.12, engine.Value);
engine.Times();
Assert.AreEqual(-0.12, engine.Value);
engine.Digit(3);
engine.Equals();
Assert.AreEqual(-0.36, engine.Value);
}