2 Why We Need Model-Based Testing

Systems with Complex State 161
Set cities = new Set("Athens", "Rome", "Athens",
"Paris", "New York", "Seattle");
Assert.AreEqual(cities.Count, 5);
You can also create a set from an IEnumerable object. Many .NET data types
support enumeration by means of IEnumerable, and this can act as an interface
between the data types used for modeling and system data types. Here is an example:
static Set ConvertToSet(IEnumerable list)
{
return new Set(list);
}
The order of elements in the enumeration doesn’t matter, and duplicate elements
will be ignored.
Note that sets themselves implement the IEnumerable interface, so they can be
used iteratively:
static int CountOdd(Set s)
{
int result = 0;
foreach(int i in s)
if (i % 2 == 1) result += 1;
return result;
}
You can expect iteration over sets to occur in an arbitrary order.
Set properties and queries
There are several properties defined for sets. You can use IsEmpty to determine if the
set has no elements. The Count property returns the number of elements contained
in a set.
You can use the Contains method to see whether a given element is in the set.
Set cities = new Set("Athens", "Rome", "Athens"};
Assert.IsFalse(cities.IsEmpty);
Assert.AreEqual(cities.Count, 2);
Assert.IsTrue(cities.Contains("Rome"));
Assert.IsFalse(cities.Contains("New York"));
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