[Grails] How to test controllers that use i18n messages.

Issue description:

1) If the controller action I want to test calls "message()" or "g.message()" then I all of my integration tests that use that line of code will error with, "No bean named 'messageSource' is defined".
2) If the controller action I want to test calls "message()" or "g.message()" then I will get the following error message.

message() is applicable for argument types: (java.util.LinkedHashMap) values

Solution Or Walk Around:

Write a ControllerUnitTestCase extension to support tests controllers that use i18n messages, then let all your unit test cases of controllers extends it.

class ExtendedControllerUnitTestCase extends ControllerUnitTestCase {

def props

protected void setUp() {

super.setUp()

props = new Properties()

def stream = new FileInputStream("grails-app/i18n/messages.properties")

props.load stream

stream.close()

mockI18N(controller)

}

def mockI18N = { controller ->

controller.metaClass.message = { Map map ->

if (!map.code)

return ""

if (map.args) {

def formatter = new MessageFormat("")

formatter.applyPattern props.getProperty(map.code)

return formatter.format(map.args.toArray())

} else {

return props.getProperty(map.code)

}

}

}

}

More info about this solution can be found: http://jira.grails.org/browse/GRAILS-5926