feat(xanthous): Describe *where* the item is in the inventory r/2681

When describing items in the inventory, both in detail and when
producing menus from those items, describe not just the item itself but
also *where* in the inventory the item is (either in the backpack, or
wielded in either or both of the hands). This uses a new
InventoryPosition datatype, and a method to get a list of items in the
inventory associated with their inventory position. When *removing*
items from the inventory (to wield, drop, or eat them), we want to make
sure we remove from the right position, so this also introduces
a `removeItemAtPosition` method to make that happen correctly.

Finally, some of the tests for this stuff was getting really slow - I
narrowed this down to runaway arbitrary generation for message
Templates, so I've tweaked the Arbitrary instance for that type to
generate smaller values.

Change-Id: I24e9948adae24b0ca9bf13955602108ca9079dcc
Reviewed-on: https://cl.tvl.fyi/c/depot/+/3228
Reviewed-by: grfn <grfn@gws.fyi>
Tested-by: BuildkiteCI

1 files changed, 18 insertions, 0 deletions

diff --git a/users/grfn/xanthous/test/Xanthous/Entities/CharacterSpec.hs b/users/grfn/xanthous/test/Xanthous/Entities/CharacterSpec.hs
index 734cce1efbbe..9210355d2dbb 100644
--- a/users/grfn/xanthous/test/Xanthous/Entities/CharacterSpec.hs
+++ b/users/grfn/xanthous/test/Xanthous/Entities/CharacterSpec.hs
@@ -3,6 +3,7 @@
 module Xanthous.Entities.CharacterSpec (main, test) where
 --------------------------------------------------------------------------------
 import           Test.Prelude
+import           Data.Vector.Lens (toVectorOf)
 --------------------------------------------------------------------------------
 import           Xanthous.Entities.Character
 import           Xanthous.Util (endoTimes)
@@ -21,4 +22,21 @@ test = testGroup "Xanthous.Entities.CharacterSpec"
           in _knuckleDamage knuckles' @?= 5
       ]
     ]
+  , testGroup "Inventory"
+    [ testProperty "items === itemsWithPosition . _2" $ \inv ->
+        inv ^.. items === inv ^.. itemsWithPosition . _2
+    , testGroup "removeItemFromPosition" $
+      let rewield w inv =
+            let (old, inv') = inv & wielded <<.~ w
+            in inv' & backpack <>~ toVectorOf (wieldedItems . wieldedItem) old
+      in [ (Backpack, \item -> backpack %~ (item ^. wieldedItem <|))
+         , (LeftHand, rewield . inLeftHand)
+         , (RightHand, rewield . inRightHand)
+         , (BothHands, rewield . review doubleHanded)
+         ] <&> \(pos, addItem) ->
+           testProperty (show pos) $ \inv item ->
+             let inv' = addItem item inv
+                 inv'' = removeItemFromPosition pos (item ^. wieldedItem) inv'
+             in inv'' ^.. items === inv ^.. items
+    ]
   ]