Groovy / Spring / Spring Security / Gmock : Last method called on mock already has a non-fixed count set

I banged my head against the wall for quite a while trying to figure this error out in my Groovy Junit tests:

Request processing failed; nested exception is java.lang.IllegalStateException: Last method called on mock already has a non-fixed count set.

I’m using Spring 4.0 with Spring Security 3.2.5 and thought maybe it was something to do with my test setup.  It turns out to be pretty straightforward.  I hadn’t wrapped my test in a play closure.  So going from this:

def r = mockMvc.perform(get("/...")).andExpect(status().isOk()).andReturn()

to this:

play {
  def r = mockMvc.perform(get("/...")).andExpect(status().isOk()).andReturn()
}

solved my problem.