json_ld: JSON-LD flattening test suite and various flattening fixes

lib/json/ld/flattening.ex

@@ -92,8 +92,8 @@ defmodule JSON.LD.Flattening do
     node = node_map[active_graph][active_subject]
 
     # 3)
-    if types = Map.get(element, "@type") do
-      types = Enum.reduce(types, [],
+    if old_types = Map.get(element, "@type") do
+      new_types = Enum.reduce(List.wrap(old_types), [],
         fn (item, types) ->
           if blank_node_id?(item) do
             identifier = generate_blank_node_id(node_id_map, item)
@@ -102,7 +102,8 @@ defmodule JSON.LD.Flattening do
             types ++ [item]
           end
         end)
-      element = Map.put(element, "@type", types)
+      element = Map.put(element, "@type",
+        if(is_list(old_types), do: new_types, else: List.first(new_types)))
     end
 
     cond do

test/suite/flatten_test.exs

@@ -0,0 +1,41 @@
+defmodule JSON.LD.TestSuite.FlattenTest do
+  use ExUnit.Case, async: false
+
+  import JSON.LD.TestSuite
+
+  setup_all do
+    [base_iri: manifest("flatten")["baseIri"]]
+  end
+
+  test_cases("flatten")
+# TODO: Ordering problems
+#  |> Enum.filter(fn %{"@id" => id} -> id in ~w[#t0034] end)
+#  |> Enum.filter(fn %{"@id" => id} -> id in ~w[#t0035] end)
+#  |> Enum.filter(fn %{"@id" => id} -> id in ~w[#t0038] end)
+# TODO: Fixed in Elixir 1.5
+#  |> Enum.filter(fn %{"@id" => id} -> id in ~w[#t0029] end)
+  |> Enum.each(fn %{"name" => name, "input" => input} = test_case ->
+      if input in ~w[flatten-0029-in.jsonld] do
+        @tag skip: """
+          probably caused by a bug in Elixirs URI.merge which should be fixed with Elixir 1.5
+          https://github.com/elixir-lang/elixir/pull/5780
+        """
+      end
+      if input in ~w[flatten-0034-in.jsonld flatten-0035-in.jsonld flatten-0038-in.jsonld] do
+        @tag skip: "TODO: Actually correct values are expanded, but the ordering is different."
+      end
+      @tag :test_suite
+      @tag :flatten_test_suite
+      @tag data: test_case
+      test "#{input}: #{name}",
+          %{data: %{"input" => input, "expect" => output} = test_case, base_iri: base_iri} do
+        context =
+          case test_case["context"] do
+            nil     -> nil
+            context -> j(context)
+          end
+        assert JSON.LD.flatten(j(input), context, test_case_options(test_case, base_iri)) == j(output)
+      end
+    end)
+
+end