chore: utility function to get stop by ID

lib/arrow/shuttles.ex

@@ -9,10 +9,12 @@ defmodule Arrow.Shuttles do
   alias ArrowWeb.ErrorHelpers
 
   alias Arrow.Gtfs.Route, as: GtfsRoute
+  alias Arrow.Gtfs.Stop, as: GtfsStop
   alias Arrow.Shuttles.KML
   alias Arrow.Shuttles.Shape
   alias Arrow.Shuttles.ShapesUpload
   alias Arrow.Shuttles.ShapeUpload
+  alias Arrow.Shuttles.Stop
 
   @doc """
   Returns the list of shapes.
@@ -331,4 +333,17 @@ defmodule Arrow.Shuttles do
     query = from(r in GtfsRoute, where: r.type in [:light_rail, :heavy_rail])
     Repo.all(query)
   end
+
+  @doc """
+  Given a stop ID, returns either an Arrow-created stop, or a
+  stop from GTFS. Prefers the Arrow-created stop if both are
+  present.
+  """
+  @spec stop_or_gtfs_stop_for_stop_id(String.t()) :: Stop.t() | GtfsStop.t() | nil
+  def stop_or_gtfs_stop_for_stop_id(id) do
+    case Repo.get_by(Stop, stop_id: id) do
+      nil -> Repo.get(GtfsStop, id)
+      stop -> stop
+    end
+  end
 end

test/arrow/shuttles_test.exs

@@ -1,9 +1,11 @@
 defmodule Arrow.ShuttlesTest do
   use Arrow.DataCase
 
+  import Arrow.Factory
   alias Arrow.Shuttles
   alias Arrow.Shuttles.Shape
   import Arrow.ShuttlesFixtures
+  import Arrow.StopsFixtures
   import Test.Support.Helpers
 
   describe "shapes with s3 functionality enabled (mocked)" do
@@ -214,4 +216,34 @@ defmodule Arrow.ShuttlesTest do
       assert %Ecto.Changeset{} = Shuttles.change_shuttle(shuttle)
     end
   end
+
+  describe "stop_or_gtfs_stop_for_stop_id/1" do
+    test "fetches Arrow stop" do
+      stop = stop_fixture()
+      stop_id = stop.stop_id
+
+      assert %Arrow.Shuttles.Stop{stop_id: ^stop_id} =
+               Shuttles.stop_or_gtfs_stop_for_stop_id(stop_id)
+    end
+
+    test "fetches GTFS stop" do
+      gtfs_stop = insert(:gtfs_stop)
+      stop_id = gtfs_stop.id
+
+      assert %Arrow.Gtfs.Stop{id: ^stop_id} = Shuttles.stop_or_gtfs_stop_for_stop_id(stop_id)
+    end
+
+    test "prefers the Arrow stop if there are both Arrow and Gtfs stops" do
+      stop = stop_fixture()
+      _gtfs_stop = insert(:gtfs_stop)
+      stop_id = stop.stop_id
+
+      assert %Arrow.Shuttles.Stop{stop_id: ^stop_id} =
+               Shuttles.stop_or_gtfs_stop_for_stop_id(stop_id)
+    end
+
+    test "returns nil if no stops are found" do
+      assert is_nil(Shuttles.stop_or_gtfs_stop_for_stop_id("nonexistent-stop"))
+    end
+  end
 end

test/support/factory.ex

@@ -67,4 +67,28 @@ defmodule Arrow.Factory do
       municipality: "Boston"
     }
   end
+
+  def gtfs_stop_factory do
+    %Arrow.Gtfs.Stop{
+      id: sequence(:source_label, &"gtfs-stop-#{&1}"),
+      code: nil,
+      name: "Test Stop",
+      desc: nil,
+      platform_code: nil,
+      platform_name: nil,
+      lat: 72.0,
+      lon: 43.0,
+      zone_id: nil,
+      address: nil,
+      url: nil,
+      level: nil,
+      location_type: :stop_platform,
+      parent_station: nil,
+      wheelchair_boarding: :accessible,
+      municipality: "Boston",
+      on_street: nil,
+      at_street: nil,
+      vehicle_type: :bus
+    }
+  end
 end