Update the all callback in ResourceFunctions to support limit and offset

Add additional option support for limits and offsets. Also refactored
to use a reduce as it makes it easier to only apply query changes
for options that are present.

lib/resource_functions.ex

@@ -104,14 +104,16 @@ defmodule EctoResource.ResourceFunctions do
   @spec all(Ecto.Repo.t(), module, term()) :: list(Ecto.Schema.t())
 
   def all(repo, schema, options \\ []) do
-    preloads = Keyword.get(options, :preloads, [])
-    order_by = Keyword.get(options, :order_by, [])
-    where = Keyword.get(options, :where, [])
-
-    schema
-    |> preload(^preloads)
-    |> order_by(^order_by)
-    |> where(^where)
+    options
+    |> Keyword.take([:preloads, :order_by, :where, :limit, :offset])
+    |> Enum.reduce(schema, fn
+      {:preloads, preloads}, query -> preload(query, ^preloads)
+      {:order_by, order_by}, query -> order_by(query, ^order_by)
+      {:where, where}, query -> where(query, ^where)
+      {:limit, limit}, query -> limit(query, ^limit)
+      {:offset, offset}, query -> offset(query, ^offset)
+      _, query -> query
+    end)
     |> repo.all([])
   end
 

test/ecto_resource/resource_functions_test.exs

@@ -0,0 +1,73 @@
+defmodule EctoResource.ResourceFunctionsTestContext.People do
+  use EctoResource
+
+  alias EctoResource.TestRepo
+  alias EctoResource.TestSchema.Person
+
+  using_repo TestRepo do
+    resource(Person)
+  end
+end
+
+defmodule EctoResource.ResourceFunctionsTest do
+  use EctoResource.RepoCase
+
+  alias EctoResource.TestSchema.Person
+  alias EctoResource.ResourceFunctionsTestContext.People
+
+  defp create_person(opts) do
+    opts = Keyword.merge([first_name: "Test", last_name: "Person", age: 42], opts)
+
+    Person |> struct(opts) |> Repo.insert!()
+  end
+
+  describe "all/2" do
+    setup do
+      michael = create_person(first_name: "Michael", age: 50)
+      dwight = create_person(first_name: "Dwight", age: 33)
+
+      %{michael: michael, dwight: dwight}
+    end
+
+    test "returns all records", %{
+      michael: michael,
+      dwight: dwight
+    } do
+      people = People.all_people()
+
+      assert michael in people
+      assert dwight in people
+    end
+
+    test "returns all records with a where clause", %{
+      michael: michael,
+      dwight: dwight
+    } do
+      assert People.all_people(where: [age: 50]) == [michael]
+      assert People.all_people(where: [age: 33]) == [dwight]
+    end
+
+    test "returns all records up to limit", %{
+      michael: michael,
+      dwight: dwight
+    } do
+      assert People.all_people(limit: 1) == [michael]
+      assert People.all_people(limit: 2) == [michael, dwight]
+    end
+
+    test "returns records in order of order_by", %{
+      michael: michael,
+      dwight: dwight
+    } do
+      assert People.all_people(order_by: :age) == [dwight, michael]
+      assert People.all_people(order_by: [desc: :age]) == [michael, dwight]
+    end
+
+    test "returns records with offset", %{
+      dwight: dwight
+    } do
+      assert People.all_people(offset: 1) == [dwight]
+      assert People.all_people(offset: 2) == []
+    end
+  end
+end