Shift everything forward a partg

part9/tests/Tests.elm

@@ -0,0 +1,70 @@
+module Tests exposing (..)
+
+import Test exposing (..)
+import Fuzz exposing (..)
+import Expect exposing (Expectation)
+import ElmHub exposing (responseDecoder)
+import Json.Decode exposing (decodeString, Value)
+import String
+
+
+all : Test
+all =
+    describe "GitHub Response Decoder"
+        [ test "it results in an Err for invalid JSON" <|
+            \() ->
+                let
+                    json =
+                        """{ "pizza": [] }"""
+
+                    isErrorResult result =
+                        -- TODO return True if the given Result is an Err of some sort,
+                        -- and False if it is an Ok of some sort.
+                        --
+                        -- Result docs: http://package.elm-lang.org/packages/elm-lang/core/4.0.1/Result
+                        False
+                in
+                    json
+                        |> decodeString responseDecoder
+                        |> isErrorResult
+                        |> Expect.true "Expected decoding an invalid response to return an Err."
+        , test "it successfully decodes a valid response" <|
+            \() ->
+                """{ "items": [
+                    /* TODO: put JSON here! */
+                 ] }"""
+                    |> decodeString responseDecoder
+                    |> Expect.equal
+                        (Ok
+                            [ { id = 5, name = "foo", stars = 42 }
+                            , { id = 3, name = "bar", stars = 77 }
+                            ]
+                        )
+        , test "it decodes one SearchResult for each 'item' in the JSON" <|
+            \() ->
+                let
+                    -- TODO convert this to a fuzz test that generates a random
+                    -- list of ids instead of this hardcoded list of three ids.
+                    --
+                    -- fuzz test docs: http://package.elm-lang.org/packages/project-fuzzball/test/2.0.1/Test#fuzz
+                    -- Fuzzer docs: http://package.elm-lang.org/packages/project-fuzzball/test/2.0.1/Fuzz
+                    ids =
+                        [ 12, 5, 76 ]
+
+                    jsonFromId id =
+                        """{"id": """ ++ toString id ++ """, "full_name": "foo", "stargazers_count": 42}"""
+
+                    jsonItems =
+                        String.join ", " (List.map jsonFromId ids)
+
+                    json =
+                        """{ "items": [""" ++ jsonItems ++ """] }"""
+                in
+                    case decodeString responseDecoder json of
+                        Ok results ->
+                            List.length results
+                                |> Expect.equal (List.length ids)
+
+                        Err err ->
+                            Expect.fail ("JSON decoding failed unexpectedly: " ++ err)
+        ]