fix(Departures): Don't hide trip_stops from trips that the vehicle isn't currently serving (#3297)

Author: joshlarson

lib/dotcom/schedule_finder/trip_details.ex

@@ -259,7 +259,10 @@ defmodule Dotcom.ScheduleFinder.TripDetails do
   defp drop_predicted_schedules_before_current_station(predicted_schedules, %Vehicle{} = vehicle),
     do:
       predicted_schedules
-      |> Enum.reject(&(PredictedSchedule.stop_sequence(&1) < vehicle.stop_sequence))
+      |> Enum.reject(
+        &(PredictedSchedule.trip_id(&1) == vehicle.trip_id &&
+            PredictedSchedule.stop_sequence(&1) < vehicle.stop_sequence)
+      )
 
   defp drop_first_trip_stop_if_vehicle_is_stopped(
          [_trip_stop_to_drop | remaining_trip_stops],

test/dotcom/upcoming_departures_test.exs

@@ -2415,6 +2415,75 @@ defmodule Dotcom.UpcomingDeparturesTest do
       assert trip_details.stops_before |> Enum.map(& &1.stop_id) == [stop_1.id, stop_2.id]
     end
 
+    test "drops all stops before the current vehicle" do
+      # Setup
+      %{
+        predicted_arrival_times: [_, _, _, arrival_time, _],
+        predictions: predictions,
+        stop_sequences: [_, _, _, stop_seq, _],
+        stops: [_stop_0, _stop_1, _stop_2, stop, _],
+        trip_id: trip_id,
+        vehicle: vehicle
+      } =
+        PredictedScheduleHelper.predicted_schedule_trip_data(
+          stop_count: 5,
+          vehicle_stop_index: 3
+        )
+
+      expect(Predictions.Repo.Mock, :all, fn _ -> predictions end)
+      expect(Schedules.Repo.Mock, :schedule_for_trip, fn ^trip_id -> [] end)
+      expect(Vehicles.Repo.Mock, :get, fn _ -> vehicle end)
+
+      # Exercise
+      trip_details =
+        UpcomingDepartures.trip_details(%{
+          now: Generators.ServiceDateTime.earlier_on_day(arrival_time),
+          stop_id: stop.id,
+          stop_sequence: stop_seq,
+          trip_id: trip_id
+        })
+
+      # Verify
+      assert trip_details.stops_before == []
+    end
+
+    test "does not drop any stops if the vehicle is serving a different trip" do
+      # Setup
+      %{
+        predicted_arrival_times: [_, _, _, arrival_time, _],
+        predictions: predictions,
+        stop_sequences: [_, _, _, stop_seq, _],
+        stops: [stop_0, stop_1, stop_2, stop, _],
+        trip_id: trip_id,
+        vehicle: vehicle
+      } =
+        PredictedScheduleHelper.predicted_schedule_trip_data(
+          stop_count: 5,
+          vehicle_stop_index: 3,
+          vehicle_on_different_trip?: true
+        )
+
+      expect(Predictions.Repo.Mock, :all, fn _ -> predictions end)
+      expect(Schedules.Repo.Mock, :schedule_for_trip, fn ^trip_id -> [] end)
+      expect(Vehicles.Repo.Mock, :get, fn _ -> vehicle end)
+
+      # Exercise
+      trip_details =
+        UpcomingDepartures.trip_details(%{
+          now: Generators.ServiceDateTime.earlier_on_day(arrival_time),
+          stop_id: stop.id,
+          stop_sequence: stop_seq,
+          trip_id: trip_id
+        })
+
+      # Verify
+      assert trip_details.stops_before |> Enum.map(& &1.stop_id) == [
+               stop_0.id,
+               stop_1.id,
+               stop_2.id
+             ]
+    end
+
     test "shows a vehicle status of :scheduled_to_depart if the trip has no predictions and all schedules are in the future" do
       # Setup
       %{