Issue 138  15th October 2018

Don't use .each in a then block!!!

When I started with Groovy, I fell into this trap. I think the issue is when you start with Groovy you don't understand that .each, .findAll, find are using closures and it seems like a funny braces syntax.

I think any one teaching Groovy should explain that given:

class Book {
    void printAuthorName(String name, Closure nameAction) {
        println nameAction(name)
   }
}

this code

Closure cls = { 
     it.toUpperCase() 
}
new Book().printAuthorName('Sergio', cls)

is equivalent to:

new Book().printAuthorName('Sergio') {
    it.toUpperCase() 
}

Closure being the last argument of a method syntax is a foreign concept for many people. It was for me.

Undo MetaClass Changes

@mrhaki:

Spock has the extension ConfineMetaClassChanges that can be used to encapsulate meta class changes to a feature method or specification. Spock replaces the original meta class with a new one before a feature method is executed. After execution of a feature method the original meta class is used again.

Grails Test Pollution

In Part 1, @sbglasius finds Spock's @ConfineMetaClassChanges not enough for his use case and creates a trait to help with metaClass mocking.

It gets really interesting in Part 2.

The problem is, that when replacing anotherService with a Stub (or Mock or Spy), testService keeps this change in subsequent test cases

By default Grails services and controllers are singletons. Thus, the same bean will be used by every integration test. Thus, if you do a replacement it will leak to the rest of the integration tests.

He creates another handy trait, the MockServiceHelper.