How to mock a HttpServletRequest's BufferedReader payload in Grails/Spock - unit-testing

Question

I have a Grails controller that expects an XML payload.
I fetch the XML payload like this in a Grails controller.
def xmlPayload = request.reader.text
That part works fine, but I'm struggling to mock this payload in a unit test.
I've tried both of the following, but the debugger is showing 'request.reader' to be null in both approaches.
Approach #1:
void "test controller method"(){
setup:
def mockBufferedReader = Mock( BufferedReader )
mockBufferedReader.getText() >> '<hello/>'
request.getReader() >> mockBufferedReader
....
Approach #2:
void "test controller method"(){
setup:
def mockBufferedReader = Mock( BufferedReader )
mockBufferedReader.getText() >> '<hello/>'
request.metaClass.getReader = { -> mockBufferedReader }
....
'request' in a unit test is a GrailsMockHttpServletRequest, so I presumed I could mock its methods like this (3rd line of both approaches), but so far no luck.
Thanks for any ideas.

Answer 1

You can do:
class EchoController {
def echo () {
render (request.reader.text)
}
}
#TestFor(EchoController)
class EchoSpec extends Specification {
def "echos XML data" () {
request.XML = '<hello/>'
when:
controller.echo ()
then:
response.text == '<hello/>'
}
}
See Testing XML and JSON Requests in Unit Testing Controllers.

Answer 2

If you only need to provide contents for a request, then you don't need to mock anything.
def "Spock works as expected"() {
given:
def request = new GrailsMockHttpServletRequest(content: '<hello/>')
when:
def result = request.getReader().getText()
then:
result == '<hello/>'
}
One purpose of such Mock classes (as in Spring Test etc.) is to avoid explicit mocking with external libraries.