Raise if passing invalid keys to structs

Closes #50

circle.yml

@@ -2,7 +2,7 @@ dependencies:
   pre:
     - wget http://packages.erlang-solutions.com/erlang-solutions_1.0_all.deb && sudo dpkg -i erlang-solutions_1.0_all.deb
     - sudo apt-get update
-    - sudo apt-get install elixir=1.0.5-2
+    - sudo apt-get install elixir
     - yes | mix deps.get
     - mix local.rebar
 test:

lib/ex_machina.ex

@@ -152,7 +152,14 @@ defmodule ExMachina do
   """
   def build(module, factory_name, attrs \\ %{}) do
     attrs = Enum.into(attrs, %{})
-    module.factory(factory_name) |> Map.merge(attrs)
+    module.factory(factory_name) |> do_merge(attrs)
+  end
+
+  defp do_merge(%{__struct__: _} = record, attrs) do
+    struct!(record, attrs)
+  end
+  defp do_merge(record, attrs) do
+    Map.merge(record, attrs)
   end
 
   @doc """

mix.exs

@@ -8,7 +8,7 @@ defmodule ExMachina.Mixfile do
     [
       app: :ex_machina,
       version: @version,
-      elixir: "~> 1.0",
+      elixir: "~> 1.2",
       description: "A factory library by the creators of FactoryGirl",
       source_url: @project_url,
       homepage_url: @project_url,

test/ex_machina_test.exs

@@ -24,6 +24,12 @@ defmodule ExMachinaTest do
       }
     end
 
+    def factory(:struct) do
+      %{
+        __struct__: Foo.Bar
+      }
+    end
+
     def save_record(record) do
       send self, {:custom_save, record}
       record
@@ -78,6 +84,12 @@ defmodule ExMachinaTest do
     }
   end
 
+  test "build/2 raises if passing invalid keys to a struct factory" do
+    assert_raise KeyError, fn ->
+      Factory.build(:struct, doesnt_exist: true)
+    end
+  end
+
   test "build_pair/2 builds 2 factories" do
     records = Factory.build_pair(:user, admin: true)