public int CompareTo(object obj)
{
NumberOfComparisons++; //I know, not thread safe but just for the sample
MyComparable mc = obj as MyComparable;
if (mc == null)
{
return(-1);
}
else
{
return(NumPart.CompareTo(mc.NumPart));
}
}
public void CompareToTest()
{
MyComparable left = new MyComparable(1);
MyComparable right = new MyComparable(2);
Assert.IsTrue(left.CompareTo(right) < 0);
Assert.IsTrue(left.CompareTo(left) == 0);
Assert.IsTrue(right.CompareTo(left) > 0);
Assert.IsTrue(left.CompareTo(null) > 0);
Assert.IsTrue(((IComparable)left).CompareTo(right) < 0);
Assert.IsTrue(((IComparable)left).CompareTo(left) == 0);
Assert.IsTrue(((IComparable)right).CompareTo(left) > 0);
Assert.IsTrue(((IComparable)left).CompareTo(null) > 0);
Assert.Throws <ArgumentException>(delegate { ((IComparable)left).CompareTo(""); });
}
public void EqualsTest()
{
MyComparable left = new MyComparable(1);
MyComparable right = new MyComparable(2);
MyComparable left2 = new MyComparable(1);
Assert.IsFalse(left.Equals(right));
Assert.IsTrue(left.Equals(left));
Assert.IsFalse(right.Equals(left));
Assert.IsTrue(left.Equals(left2));
Assert.IsFalse(left.Equals(null));
Assert.IsFalse(((object)left).Equals(right));
Assert.IsTrue(((object)left).Equals(left));
Assert.IsFalse(((object)right).Equals(left));
Assert.IsTrue(((object)left).Equals(left2));
Assert.IsFalse(((object)left).Equals(null));
}
public void CallingMethodThroughIComparableInterfaceInvokesImplementingMethod()
{
MyComparable a = new MyComparable(), b = new MyComparable();
a.result = 534;
Assert.AreEqual(534, ((IComparable <MyComparable>)a).CompareTo(b));
Assert.AreStrictEqual(b, a.other);
a.result = -42;
Assert.AreEqual(-42, ((IComparable <MyComparable>)a).CompareTo(null));
Assert.AreStrictEqual(null, a.other);
a.result = -534;
Assert.AreEqual(-534, a.CompareTo(b));
Assert.AreStrictEqual(b, a.other);
a.result = 42;
Assert.AreEqual(42, a.CompareTo(null));
Assert.AreStrictEqual(null, a.other);
}
public void CallingMethodThroughIComparableInterfaceInvokesImplementingMethod()
{
MyComparable a = new MyComparable(), b = new MyComparable();
a.result = 534;
Assert.AreEqual(((IComparable <MyComparable>)a).CompareTo(b), 534);
Assert.AreStrictEqual(a.other, b);
a.result = -42;
Assert.AreEqual(((IComparable <MyComparable>)a).CompareTo(null), -42);
Assert.AreStrictEqual(a.other, null);
a.result = -534;
Assert.AreEqual(a.CompareTo(b), -534);
Assert.AreStrictEqual(a.other, b);
a.result = 42;
Assert.AreEqual(a.CompareTo(null), 42);
Assert.AreStrictEqual(a.other, null);
}