Couldn't match expected type ‘Post’ with actual type ‘Route App’

I'm trying to use the function postBody

postBody :: (Yesod site, RedirectUrl site url) => url -> ByteString -> YesodExample site () 

from the Yesod.Test package. The documentation says it can be used like this

import Data.Aeson
postBody HomeR (encode $ object ["age" .= (1 :: Integer)])

However when I tried to use it in my app

    describe "Posts" $ do
        it "posts post and returns post" $ do
            postBody PostR (encode $ object [
                "body" .= ("test post" :: Text),
                "title" .= ("test post" :: Text),
                "coverImage" .= ("test post" :: Text),
                "author" .= (0 :: Int)
                ])
            statusIs 200

I got the error

• Couldn't match expected type ‘Post’ with actual type ‘Route App’
• In the first argument of ‘postBody’, namely ‘PostR’
  In a stmt of a 'do' block:
    postBody
      PostR
      (encode
       $ object
           ["body" .= ("test post" :: Text), "title" .= ("test post" :: Text),

            "coverImage" .= ("test post" :: Text), "author" .= (0 :: Int)])
  In the second argument of ‘($)’, namely
    ‘do { postBody
            PostR
            (encode
             $ object
                 ["body" .= ("test post" :: Text), "title" .= ("test post" :: Text),
                  ....]);
          statusIs 200 }’

My usage seems to be the same as the example so I can't see why it would fail.

PostR is in the routes file here

/posts PostR POST

and the handler for it

postPostR :: Handler Value
postPostR = do
    post <- requireJsonBody :: Handler Post
    maybeUserID <- maybeAuthId
    case maybeUserID of
        Just userID -> do
            let post' = post {postAuthor = userID}
            inserted <- runDB $ insertEntity post'
            returnJson inserted
        Nothing -> sendResponseStatus status403 ("Unauthorized" :: Text)

The problem ended up being that in the posts table there was a column body so Yesod created postBody for this which conflicted with the postBody from Yesod.Test.

The solution is using a qualified import on yesod test

import qualified Yesod.Test as T