Programming Groovy 2

18.8 Mocking Using Expando

So far in this chapter we’ve looked at ways to mock instance methods called from within another instance method. In the rest of this chapter, we’ll look at ways to mock other objects on which our code depends.

Let’s take a look at an example. Suppose the methods of a class we’re interested in testing depend on a ​File​. That’ll make it hard to write a unit test. We need to find ways to mock this object so our unit tests on our class can be quick and automated:

package com.agiledeveloper

public class ClassWithDependency
{
  def methodA(val, file)
  {
    file.write "The value is ${val}."
  }
  def methodB(val)
  {
    def file =  ...