Fix equality check for bytes.

Should fix gren-lang#48

Using suggested fix from https://github.com/elm/core/pull/1092/files

src/Gren/Kernel/Utils.js

@@ -55,6 +55,20 @@ function _Utils_eqHelp(x, y, depth, stack) {
 	}
 	//*/
 
+  if (typeof DataView === "function" && x instanceof DataView) {
+    var length = x.byteLength;
+
+    if (y.byteLength !== length) {
+      return false;
+    }
+
+    for (var i = 0; i < length; ++i) {
+      if (x.getUint8(i) !== y.getUint8(i)) {
+        return false;
+      }
+    }
+  }
+
   if (Array.isArray(x) && x.length !== y.length) {
     return false;
   }

tests/src/Main.gren

@@ -8,6 +8,7 @@ import Test exposing (..)
 import Test.Array as Array
 import Test.Basics as Basics
 import Test.Bitwise as Bitwise
+import Test.Bytes as Bytes
 import Test.Char as Char
 import Test.CodeGen as CodeGen
 import Test.Dict as Dict
@@ -28,6 +29,7 @@ main =
             [ Array.tests
             , Basics.tests
             , Bitwise.tests
+            , Bytes.tests
             , Char.tests
             , CodeGen.tests
             , Dict.tests

tests/src/Test/Bytes.gren

@@ -0,0 +1,35 @@
+module Test.Bytes exposing (tests)
+
+import Bytes exposing (Bytes)
+import Bytes.Encode
+import Expect
+import Fuzz
+import Test exposing (..)
+
+
+encodeString : String -> Bytes
+encodeString s =
+    Bytes.Encode.encode <|
+        Bytes.Encode.string s
+
+
+encodeInt : Int -> Bytes
+encodeInt i =
+    Bytes.Encode.encode <|
+        Bytes.Encode.signedInt8 i
+
+
+tests : Test
+tests =
+    describe "Byte comparison"
+        [ fuzz Fuzz.string "same strings are equal" <| \s ->
+            Expect.equal (encodeString s) (encodeString s)
+        , fuzz (Fuzz.intRange -128 127) "same ints are equal" <| \i ->
+            Expect.equal (encodeInt i) (encodeInt i)
+        , fuzz Fuzz.string "different strings are not equal" <| \s ->
+            Expect.notEqual (encodeString s) (encodeString (s ++ "a"))
+        , fuzz (Fuzz.intRange -100 100) "different ints are not equal" <| \i ->
+            Expect.notEqual (encodeInt i) (encodeInt (i + 1))
+        , fuzz2 Fuzz.string (Fuzz.intRange 1 127) "string and int are not equal" <| \s i ->
+            Expect.notEqual (encodeString s) (encodeInt i)
+        ]