From f74ecb5643eed63b6beed83c3d9a944f752d288f Mon Sep 17 00:00:00 2001
From: Geoff Lane <geoff@zorched.net>
Date: Tue, 5 Jul 2016 11:17:05 -0400
Subject: [PATCH 1/3] Only drop autogenerated ids and not domain ids

---
 lib/ex_machina/ecto.ex        | 11 ++++++++++-
 test/ex_machina/ecto_test.exs |  7 +++++++
 test/support/models/custom.ex |  9 +++++++++
 test/support/test_factory.ex  |  6 ++++++
 4 files changed, 32 insertions(+), 1 deletion(-)
 create mode 100644 test/support/models/custom.ex

diff --git a/lib/ex_machina/ecto.ex b/lib/ex_machina/ecto.ex
index 33bbc7b..b80cc80 100644
--- a/lib/ex_machina/ecto.ex
+++ b/lib/ex_machina/ecto.ex
@@ -121,9 +121,18 @@ defmodule ExMachina.Ecto do
     |> Map.from_struct
     |> Map.delete(:__meta__)
     |> Map.drop(struct.__schema__(:associations))
-    |> Map.drop(struct.__schema__(:primary_key))
+    |> drop_autogenerated_ids(struct)
   end
   defp drop_ecto_fields(record) do
     raise ArgumentError, "#{inspect record} is not an Ecto model. Use `build` instead."
   end
+
+  # Don't want to drop non-autogenrated ids because those are meaningful to the
+  # domain in some way and will be expected to be set explicitly
+  defp drop_autogenerated_ids(map, struct) do
+    case struct.__schema__(:autogenerate_id) do
+      nil -> map
+      {name, _type} -> Map.delete(map, name)
+    end
+  end
 end
diff --git a/test/ex_machina/ecto_test.exs b/test/ex_machina/ecto_test.exs
index 1586e49..477c533 100644
--- a/test/ex_machina/ecto_test.exs
+++ b/test/ex_machina/ecto_test.exs
@@ -37,6 +37,13 @@ defmodule ExMachina.EctoTest do
     }
   end
 
+  test "params_for/2 leaves ids that are not auto-generated" do
+    assert TestFactory.params_for(:custom) == %{
+      custom_id: 1,
+      name: "Testing"
+    }
+  end
+
   test "params_for/2 raises when passed a map" do
     assert_raise ArgumentError, fn ->
       TestFactory.params_for(:user_map)
diff --git a/test/support/models/custom.ex b/test/support/models/custom.ex
new file mode 100644
index 0000000..ed8563e
--- /dev/null
+++ b/test/support/models/custom.ex
@@ -0,0 +1,9 @@
+defmodule ExMachina.Custom do
+  use Ecto.Schema
+
+  @primary_key {:custom_id, :integer, []}
+  schema "customs" do
+    field :name, :string
+  end
+end
+
diff --git a/test/support/test_factory.ex b/test/support/test_factory.ex
index c1b8fae..06a7e19 100644
--- a/test/support/test_factory.ex
+++ b/test/support/test_factory.ex
@@ -1,6 +1,12 @@
 defmodule ExMachina.TestFactory do
   use ExMachina.Ecto, repo: ExMachina.TestRepo
 
+  def custom_factory do
+    %ExMachina.Custom{
+      custom_id: 1,
+      name: "Testing"
+    }
+  end
   def user_factory do
     %ExMachina.User{
       name: "John Doe",

From 05a2c0738c6e9bf0c23dcf216b75cba455be6b65 Mon Sep 17 00:00:00 2001
From: Geoff Lane <geoff@zorched.net>
Date: Tue, 5 Jul 2016 11:27:19 -0400
Subject: [PATCH 2/3] Cleanups from feedback

---
 test/ex_machina/ecto_test.exs | 2 +-
 test/support/models/custom.ex | 2 +-
 test/support/test_factory.ex  | 3 ++-
 3 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/test/ex_machina/ecto_test.exs b/test/ex_machina/ecto_test.exs
index 477c533..4c3c647 100644
--- a/test/ex_machina/ecto_test.exs
+++ b/test/ex_machina/ecto_test.exs
@@ -39,7 +39,7 @@ defmodule ExMachina.EctoTest do
 
   test "params_for/2 leaves ids that are not auto-generated" do
     assert TestFactory.params_for(:custom) == %{
-      custom_id: 1,
+      non_autogenerated_id: 1,
       name: "Testing"
     }
   end
diff --git a/test/support/models/custom.ex b/test/support/models/custom.ex
index ed8563e..0a987fb 100644
--- a/test/support/models/custom.ex
+++ b/test/support/models/custom.ex
@@ -1,7 +1,7 @@
 defmodule ExMachina.Custom do
   use Ecto.Schema
 
-  @primary_key {:custom_id, :integer, []}
+  @primary_key {:non_autogenerated_id, :integer, []}
   schema "customs" do
     field :name, :string
   end
diff --git a/test/support/test_factory.ex b/test/support/test_factory.ex
index 06a7e19..8518908 100644
--- a/test/support/test_factory.ex
+++ b/test/support/test_factory.ex
@@ -3,10 +3,11 @@ defmodule ExMachina.TestFactory do
 
   def custom_factory do
     %ExMachina.Custom{
-      custom_id: 1,
+      non_autogenerated_id: 1,
       name: "Testing"
     }
   end
+
   def user_factory do
     %ExMachina.User{
       name: "John Doe",

From 278b5700dbffacbc184ad9cc8d59ff64eeaa4b56 Mon Sep 17 00:00:00 2001
From: Geoff Lane <geoff@zorched.net>
Date: Tue, 5 Jul 2016 11:28:48 -0400
Subject: [PATCH 3/3] Remove comment

explained by test
---
 lib/ex_machina/ecto.ex | 2 --
 1 file changed, 2 deletions(-)

diff --git a/lib/ex_machina/ecto.ex b/lib/ex_machina/ecto.ex
index b80cc80..1969f22 100644
--- a/lib/ex_machina/ecto.ex
+++ b/lib/ex_machina/ecto.ex
@@ -127,8 +127,6 @@ defmodule ExMachina.Ecto do
     raise ArgumentError, "#{inspect record} is not an Ecto model. Use `build` instead."
   end
 
-  # Don't want to drop non-autogenrated ids because those are meaningful to the
-  # domain in some way and will be expected to be set explicitly
   defp drop_autogenerated_ids(map, struct) do
     case struct.__schema__(:autogenerate_id) do
       nil -> map