[Groovy] Class StubFor

class StubFor
extends Object

StubFor supports (typically unit) testing of classes in isolation by allowing a loosely-ordered expectation of the behavior of collaborators to be defined. A typical test scenario involves a class under test (CUT) and one or more collaborators. In such a scenario it is often desirable to just test the business logic of the CUT. One strategy for doing that is to replace the collaborator instances with simplified stub objects to help isolate out the logic in the CUT. StubFor allows such stubs to be created using meta-programming. The desired behavior of collaborators is defined as a behavior specification. The behavior can be checked by the user using verify(). With StubFor, a stub's expectation is sequence independent and use of verify() is left to the user. Typical usage is as follows: <

 import groovy.mock.interceptor.StubFor

 class Person {
   String first, last
 }

 class Family {
   Person mother, father
   def nameOfFather() { "$father.first $father.last" }
 }

 def stub = new StubFor(Person)
 stub.demand.with {
   getLast{ 'name' }
   getFirst{ 'dummy' }
 }
 stub.use {
   def john = new Person(first:'John', last:'Smith')
   def f = new Family(father:john)
   assert f.nameOfFather() == 'dummy name'
 }
 stub.expect.verify()
 

Here, Family is our class under test and Person is the collaborator. We are using normal Groovy property semantics here; hence the statement father.first causes a call to father.getFirst() to occur. For a complete list of features, see: MockFor.