Bearded-android-docs

Created Sunday 27 April 2014

• use on singleton classes and other static classes
• add a setter method that allows you to replace the singleton with a fake/mock for testing
• you usually also add helper methods to help testing

class Singleton
{
    static private Singleton instance = null;

    static public void setTestingInstance(Singleton newInstance)
    {

instance = newInstance

}

static public Singleton getInstance()
{

return instance == null ? new Singleton() : instance;

}

static public void resetForTesting()
{

instance = null;

}
}

Unfortunately, this approach has several downsides when you don't use Spring or another IoC framework:

• You are adding methods that should be called only in unit tests
• You have to make the constructor to the singleton not private.

• use an Ioc framework
• use reflection to replace the instance of the singleton object

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