chapter 6: Replace unit by property test

tests/PhotoGrooveTest.elm

@@ -3,6 +3,7 @@ module PhotoGrooveTest exposing (..)
 import Expect exposing (Expectation)
 import Fuzz exposing (Fuzzer, int, list, string)
 import Json.Decode as J
+import Json.Encode as Encode exposing (Value)
 import PhotoGroove as Testee
 import Test exposing (..)
 
@@ -10,10 +11,16 @@ import Test exposing (..)
 suite : Test
 suite =
     describe "photoDecoder"
-        [ test "title defaults to '(untitled)'" <|
-            \_ ->
-                """{"url": "example.com", "size": 5}"""
-                    |> J.decodeString Testee.photoDecoder
-                    |> Result.map (\p -> p.title)
+        [ fuzz2 Fuzz.string Fuzz.int "title always defaults to '(untitled)'" <|
+            \url size ->
+                mkPhoto url size
+                    |> J.decodeValue Testee.photoDecoder
+                    |> Result.map .title
                     |> Expect.equal (Ok "(untitled)")
         ]
+
+
+mkPhoto : String -> Int -> Value
+mkPhoto url size =
+    [ ( "url", Encode.string url ), ( "size", Encode.int size ) ]
+        |> Encode.object