Add isEqual function for Hashdict + tests

src/Internal/Tools/Hashdict.elm

@@ -4,7 +4,7 @@ module Internal.Tools.Hashdict exposing
     , isEmpty, member, memberKey, get, size
     , keys, values, toList, fromList
     , rehash, union
-    , encode, decoder, softDecoder
+    , encode, decoder, softDecoder, isEqual
     )
 
 {-| This module abstracts the `Dict` type with one function that assigns a
@@ -25,7 +25,7 @@ This allows you to store values based on an externally defined identifier.
 
 ## Query
 
-@docs isEmpty, member, memberKey, get, size
+@docs isEmpty, member, memberKey, get, size, isEqual
 
 
 ## Lists
@@ -150,6 +150,12 @@ insert : a -> Hashdict a -> Hashdict a
 insert v (Hashdict h) =
     Hashdict { h | values = Dict.insert (h.hash v) v h.values }
 
+{-| Since the Hashdict contains a hash function, the == operator does not work
+simply. Instead, you should use the isEqual operator.
+-}
+isEqual : Hashdict a -> Hashdict a -> Bool
+isEqual h1 h2 =
+    toList h1 == toList h2
 
 {-| Determine if a hashdict is empty.
 -}

tests/Test/Tools/Hashdict.elm

@@ -13,19 +13,88 @@ fuzzer : (a -> String) -> Fuzzer a -> Fuzzer (Hashdict a)
 fuzzer toHash fuz =
     Fuzz.map (Hashdict.fromList toHash) (Fuzz.list fuz)
 
+eventFuzzer : Fuzzer (Hashdict Event.Event)
+eventFuzzer =
+    fuzzer .eventId TestEvent.fuzzer
+
 suite : Test
 suite =
     describe "Hashdict"
-        [ describe "init"
-            [ test "init isEmpty"
+        [ describe "empty"
+            [ test "empty isEmpty"
                 ( Hashdict.empty identity
                     |> Hashdict.isEmpty
                     |> Expect.equal True
                     |> always
                 )
+            , fuzz TestEvent.fuzzer "Nothing is member"
+                (\event ->
+                    Hashdict.empty .eventId
+                        |> Hashdict.member event
+                        |> Expect.equal False
+                )
+            , fuzz Fuzz.string "No key is member"
+                (\key ->
+                    Hashdict.empty identity
+                        |> Hashdict.memberKey key
+                        |> Expect.equal False
+                )
+            , fuzz Fuzz.string "Get gets Nothing"
+                (\key ->
+                    Hashdict.empty identity
+                        |> Hashdict.get key
+                        |> Expect.equal Nothing
+                )
+            , test "Size is zero"
+                ( Hashdict.empty identity
+                    |> Hashdict.size
+                    |> Expect.equal 0
+                    |> always
+                )
+            , test "No keys"
+                ( Hashdict.empty identity
+                    |> Hashdict.keys
+                    |> Expect.equal []
+                    |> always
+                )
+            , test "No values"
+                ( Hashdict.empty identity
+                    |> Hashdict.values
+                    |> Expect.equal []
+                    |> always
+                )
+            , test "To list is []"
+                ( Hashdict.empty identity
+                    |> Hashdict.toList
+                    |> Expect.equal []
+                    |> always
+                )
+            , test "From list is empty"
+                ( []
+                    |> Hashdict.fromList (\x -> x)
+                    |> Hashdict.isEqual (Hashdict.empty identity)
+                    |> Expect.equal True
+                    |> always
+                )
+            , test "Empty + empty == empty"
+                ( Hashdict.empty identity
+                    |> Hashdict.union (Hashdict.empty String.toUpper)
+                    |> Hashdict.isEqual (Hashdict.empty String.toLower)
+                    |> Expect.equal True
+                    |> always
+                )
+            , fuzz (Fuzz.intRange 0 10) "JSON encode -> JSON decode"
+                (\indent ->
+                    Hashdict.empty identity
+                        |> Hashdict.encode E.string
+                        |> E.encode indent
+                        |> D.decodeString (Hashdict.decoder identity D.string)
+                        |> Result.map (Hashdict.isEqual (Hashdict.empty String.toUpper))
+                        |> Expect.equal (Ok True)
+                )
             ]
         , describe "JSON"
-            [ fuzz2 (fuzzer .eventId TestEvent.fuzzer) (Fuzz.intRange 0 10) "JSON encode -> JSON decode"
+            [ fuzz2 eventFuzzer (Fuzz.intRange 0 10) "JSON encode -> JSON decode"
                 (\hashdict indent ->
                     hashdict
                         |> Hashdict.encode Event.encode