refactor(users/glittershark): Rename to grfn

Rename my //users directory and all places that refer to glittershark to
grfn, including nix references and documentation.

This may require some extra attention inside of gerrit's database after
it lands to allow me to actually push things.

Change-Id: I4728b7ec2c60024392c1c1fa6e0d4a59b3e266fa
Reviewed-on: https://cl.tvl.fyi/c/depot/+/2933
Tested-by: BuildkiteCI
Reviewed-by: tazjin <mail@tazj.in>
Reviewed-by: lukegb <lukegb@tvl.fyi>
Reviewed-by: glittershark <grfn@gws.fyi>

users/grfn/xanthous/test/Xanthous/Data/EntityMapSpec.hs

@@ -0,0 +1,69 @@
+{-# LANGUAGE ApplicativeDo #-}
+--------------------------------------------------------------------------------
+module Xanthous.Data.EntityMapSpec where
+--------------------------------------------------------------------------------
+import           Test.Prelude
+--------------------------------------------------------------------------------
+import qualified Data.Aeson as JSON
+--------------------------------------------------------------------------------
+import           Xanthous.Data.EntityMap
+import           Xanthous.Data (Positioned(..))
+--------------------------------------------------------------------------------
+
+main :: IO ()
+main = defaultMain test
+
+test :: TestTree
+test = localOption (QuickCheckTests 20)
+  $ testGroup "Xanthous.Data.EntityMap"
+  [ testBatch $ monoid @(EntityMap Int) mempty
+  , testGroup "Deduplicate"
+    [ testGroup "Semigroup laws"
+      [ testProperty "associative" $ \(a :: Deduplicate (EntityMap Int)) b c ->
+          a <> (b <> c) === (a <> b) <> c
+      ]
+    ]
+  , testGroup "Eq laws"
+    [ testProperty "reflexivity" $ \(em :: EntityMap Int) ->
+        em == em
+    , testProperty "symmetric" $ \(em₁ :: EntityMap Int) em₂ ->
+        (em₁ == em₂) == (em₂ == em₁)
+    , testProperty "transitive" $ \(em₁ :: EntityMap Int) em₂ em₃ ->
+        if (em₁ == em₂ && em₂ == em₃)
+        then (em₁ == em₃)
+        else True
+    ]
+  , testGroup "JSON encoding/decoding"
+    [ testProperty "round-trips" $ \(em :: EntityMap Int) ->
+        let em' = JSON.decode (JSON.encode em)
+        in counterexample (show (em' ^? _Just . lastID, em ^. lastID
+                                , em' ^? _Just . byID == em ^. byID . re _Just
+                                , em' ^? _Just . byPosition == em ^. byPosition . re _Just
+                                , em' ^? _Just . _EntityMap == em ^. _EntityMap . re _Just
+                                ))
+           $ em' === Just em
+    , testProperty "Preserves IDs" $ \(em :: EntityMap Int) ->
+        let Just em' = JSON.decode $ JSON.encode em
+        in toEIDsAndPositioned em' === toEIDsAndPositioned em
+    ]
+
+  , localOption (QuickCheckTests 50)
+  $ testGroup "atPosition"
+    [ testProperty "setget" $ \pos (em :: EntityMap Int) es ->
+        view (atPosition pos) (set (atPosition pos) es em) === es
+    , testProperty "getset" $ \pos (em :: EntityMap Int) ->
+        set (atPosition pos) (view (atPosition pos) em) em === em
+    , testProperty "setset" $ \pos (em :: EntityMap Int) es ->
+        (set (atPosition pos) es . set (atPosition pos) es) em
+        ===
+        set (atPosition pos) es em
+      -- testProperty "lens laws" $ \pos -> isLens $ atPosition @Int pos
+    , testProperty "preserves IDs" $ \(em :: EntityMap Int) e1 e2 p ->
+        let (eid, em') = insertAtReturningID p e1 em
+            em'' = em' & atPosition p %~ (e2 <|)
+        in
+          counterexample ("em': " <> show em')
+          . counterexample ("em'': " <> show em'')
+          $ em'' ^. at eid === Just (Positioned p e1)
+    ]
+  ]