Beautiful

gistfile1.hs

-- | Test something with an in-memory acid-state
acidTest :: forall event query result.
         (UpdateEvent event, MethodState event ~ HerbertState,
          QueryEvent query, MethodState query ~ HerbertState,
          MethodResult query ~ result)
         => String           -- ^ Test description
         -> HerbertState     -- ^ Initial state for test
         -> event            -- ^ Event to test
         -> query            -- ^ Query to check
         -> (result -> Bool) -- ^ Function to test query result
         -> Assertion
acidTest desc initialState event query' checker = do
    state <- openMemoryState initialState
    update state event
    result <- query state query'
    assertBool desc $ checker result