Question

EDIT: Please let me be clear, I’m asking how to do this in Grails using Spring Dependency Injection, and NOT Grails’ metaclass functionality or new().

I have a grails service that is for analyzing log files. Inside the service I use the current time for lots of things. For unit testing I have several example log files that I parse with this service. These have times in them obviously.

I want my service, DURING UNIT TESTING to think that the current time is no more than a few hours after the last logging statement in my example log files.

So, I’m willing to this:

class MyService {
    def currentDate = { -> new Date() }

    def doSomeStuff() {
        // need to know when is "right now"
        Date now = currentDate()
    }
}

So, what I want to be able to do is have currentDate injected or set to be some other HARDCODED time, like

currentDate = { -> new Date(1308619647140) }

Is there not a way to do this with some mockWhatever method inside my unit test? This kind of stuff was super easy with Google Guice, but I have no idea how to do it in Spring.

It’s pretty frustrating that when I Google “grails dependency injection” all I find are examples of

class SomeController {
  // wow look how amazing this is, it's injected automatically!!
  // isn't spring incredible OMG!
  def myService
}

It feels like all that’s showing me is that I don’t have to type new …()

Where do I tell it that when environment equals test, then do this:

currentDate = { -> new Date(1308619647140) }

Am I just stuck setting this property manually in my test??

I would prefer not to have to create a “timeService” because this seems silly considering I just want 1 tiny change.

Answer 1

Thanks for the help guys. The best solution I could come up with for using Spring DI in this case was to do the following in

resources.groovy

These are the two solutions I found:

1: If I want the timeNowService to be swapped for testing purposes everywhere:

import grails.util.GrailsUtil

// Place your Spring DSL code here
beans = {
    if (GrailsUtil.environment == 'test') {
        println ">>> test env"
        timeNowService(TimeNowMockService)
    } else {
        println ">>> not test env"
        timeNowService(TimeNowService)
    }
}

2: I could do this if I only want this change to apply to this particular service:

import grails.util.GrailsUtil

// Place your Spring DSL code here
beans = {

    if (GrailsUtil.environment == 'test') {
        println ">>> test env"
        time1(TimeNowMockService)
    } else {
        println ">>> not test env"
        time1(TimeNowService)
    }
    myService(MyService) {
        diTest = 'hello 2'
        timeNowService = ref('time1')
    }
}

In either case I would use the service by calling
timeNowService.now().
The one strange, and very frustrating thing to me was that I could not do this:

import grails.util.GrailsUtil
// Place your Spring DSL code here
beans = {
    if (GrailsUtil.environment == 'test') {
        println ">>> test env"
        myService(MyService) {
            timeNow = { -> new Date(1308486447140) }
        }
    } else {
        println ">>> not test env"
        myService(MyService) {
            timeNow = { -> new Date() }
        }
    }
}

In fact, when I tried that I also had a dummy value in there, like dummy = 'hello 2' and then a default value of dummy = 'hello' in the myService class itself. And when I did this 3rd example with the dummy value set in there as well, it silently failed to set, apparently b/c timeNow blew something up in private.

I would be interested to know if anyone could explain why this fails.

Thanks for the help guys and sorry to be impatient…