2 Why We Need Model-Based Testing

Systems with Complex State 163
system. For example, a server may have an operation that assigns integer priorities
to its active clients:
static Map priority = Map.EmptyMap;
[Action]
static void SetPriority(string client, int p)
{
priority = priority.Override(client, p);
}
The Override method produces a new map by substituting a key/value pair. If the
key given as the argument is not in the map, then a new key/value pair is added. In
this example we set the variable priority to contain the value of the new map.
Creating maps
If your map contains five or fewer key/value pairs, you can use a map constructor
that takes keys and values as arguments:
Map cityId = new Map("Athens", 1, "Rome", 2,
"Paris", 3, "New York", 4);
Assert.AreEqual(cityId["Paris"], 3);
A common way to build a map is to start with the empty map and add elements
programmatically:
Map idCity = Map.EmptyMap;
string[] cities =
new string[]{"Athens", "Rome", "Paris", "New York"};
for(int i = 0; i < cities.Length; i += 1)
idCity = idCity.Add(i + 100, city[i]);
Assert.AreEqual(idCity[102], "Paris");
Map lookup operations
The lookup operations for a map are very similar to those of a .NET dictionary.
If you need to look up the value of a key, you may use the C# indexer syntax:
Map cityState =
new Map("Athens", "GA", "Paris", "TX"};
Assert.AreEqual(cityState["Paris"], "TX");
more free ebooks download links at:
http://www.ebook-x.com