fixes #50

Author: zookzook

lib/mongo.ex

@@ -659,7 +659,6 @@ defmodule Mongo do
   @spec find_one(GenServer.server, collection, BSON.document, Keyword.t) :: BSON.document | nil
   def find_one(topology_pid, coll, filter, opts \\ []) do
     opts = opts
-           |> Keyword.delete(:sort)
            |> Keyword.put(:limit, 1)
            |> Keyword.put(:batch_size, 1)
 

test/mongo/find_one_test.exs

@@ -0,0 +1,24 @@
+defmodule Mongo.Test do
+  use ExUnit.Case
+
+  setup_all do
+    assert {:ok, pid} = Mongo.TestConnection.connect
+    {:ok, [pid: pid]}
+  end
+
+  test "find_one, using :sort options", %{pid: top} do
+
+    coll = "find_one_sort"
+    Mongo.insert_one(top, coll, %{name: "Greta", age: 10})
+    Mongo.insert_one(top, coll, %{name: "Tom", age: 13})
+    Mongo.insert_one(top, coll, %{name: "Waldo", age: 5})
+    Mongo.insert_one(top, coll, %{name: "Oska", age: 3})
+
+    assert {:ok, 4} == Mongo.count(top, coll, %{})
+
+    assert %{"name" => "Greta"} == Mongo.find_one(top, coll, %{}, sort: %{name: 1}) |> Map.take(["name"])
+    assert %{"name" => "Waldo"} == Mongo.find_one(top, coll, %{}, sort: %{name: -1}) |> Map.take(["name"])
+    assert %{"name" => "Oska"} == Mongo.find_one(top, coll, %{}, sort: %{age: 1}) |> Map.take(["name"])
+    assert %{"name" => "Tom"} == Mongo.find_one(top, coll, %{}, sort: %{age: -1}) |> Map.take(["name"])
+  end
+end