chapter 6: Add unit-tests

elm.json

@@ -23,7 +23,9 @@
         }
     },
     "test-dependencies": {
-        "direct": {},
+        "direct": {
+            "elm-explorations/test": "2.1.2"
+        },
         "indirect": {}
     }
 }

src/PhotoGroove.elm

@@ -1,4 +1,4 @@
-port module PhotoGroove exposing (main)
+port module PhotoGroove exposing (main, photoDecoder)
 
 import Browser
 import Html exposing (Attribute, Html, button, canvas, div, h1, h3, img, input, label, node, text)

tests/PhotoGrooveTest.elm

@@ -0,0 +1,19 @@
+module PhotoGrooveTest exposing (..)
+
+import Expect exposing (Expectation)
+import Fuzz exposing (Fuzzer, int, list, string)
+import Json.Decode as J
+import PhotoGroove as Testee
+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)
+                    |> Expect.equal (Ok "(untitled)")
+        ]