fix(DownstreamAlerts): Exclude the target stop's alerts from downstream calc

shared/src/commonMain/kotlin/com/mbta/tid/mbta_app/model/Alert.kt

@@ -239,8 +239,9 @@ data class Alert(
         }
 
         /**
-         * Gets the alerts of the first stop that is downstream of the target stop which has alerts.
-         * Considers only alerts that have specified stops.
+         * Gets the alerts of the first stop that is downstream of the target stop which has any
+         * alerts that are different from the alerts at the target stop. Considers only alerts that
+         * have specified stops.
          *
          * @param alerts: The full list of alerts
          * @param trip: The trip used to calculate downstream stops
@@ -255,19 +256,32 @@ data class Alert(
 
             val alerts = alerts.filter { it.hasStopsSpecified }
 
+            val targetStopAlertIds =
+                applicableAlerts(
+                        alerts.toList(),
+                        trip.directionId,
+                        listOf(trip.routeId),
+                        targetStopWithChildren
+                    )
+                    .map { it.id }
+                    .toSet()
+
             val indexOfTargetStopInPattern =
                 stopIds.indexOfFirst { targetStopWithChildren.contains(it) }
             if (indexOfTargetStopInPattern != -1 && indexOfTargetStopInPattern < stopIds.size - 1) {
                 val downstreamStops = stopIds.subList(indexOfTargetStopInPattern + 1, stopIds.size)
                 val firstStopAlerts =
                     downstreamStops
                         .map { stop ->
-                            applicableAlerts(
-                                alerts.toList() ?: listOf(),
-                                trip.directionId,
-                                listOf(trip.routeId),
-                                setOf(stop)
-                            )
+                            val alerts =
+                                applicableAlerts(
+                                        alerts.toList(),
+                                        trip.directionId,
+                                        listOf(trip.routeId),
+                                        setOf(stop)
+                                    )
+                                    .filter { !targetStopAlertIds.contains(it.id) }
+                            alerts
                         }
                         .firstOrNull { alerts -> !alerts.isNullOrEmpty() }
                         ?: listOf()

shared/src/commonTest/kotlin/com/mbta/tid/mbta_app/model/AlertTest.kt

@@ -318,6 +318,70 @@ class AlertTest {
     }
 
 
+    @Test
+    fun `downstreamAlerts excludes alerts affecting the target stop`() {
+        val objects = ObjectCollectionBuilder()
+        val route = objects.route()
+        val targetStop = objects.stop()
+        val downstreamStop1 = objects.stop()
+        val downstreamStop2 = objects.stop()
+
+        val alertAllStops =
+            objects.alert {
+                informedEntity(
+                    listOf(Alert.InformedEntity.Activity.Board),
+                    route = route.id,
+                    stop = targetStop.id,
+                    directionId = 0
+                )
+                informedEntity(
+                    listOf(Alert.InformedEntity.Activity.Board),
+                    route = route.id,
+                    stop = downstreamStop1.id,
+                    directionId = 0
+                )
+                informedEntity(
+                    listOf(Alert.InformedEntity.Activity.Board),
+                    route = route.id,
+                    stop = downstreamStop2.id,
+                    directionId = 0
+                )
+            }
+
+        val alertDownstream2Only =
+            objects.alert {
+                informedEntity(
+                    listOf(Alert.InformedEntity.Activity.Board),
+                    route = route.id,
+                    stop = downstreamStop2.id,
+                    directionId = 0
+                )
+            }
+
+        val trip =
+            objects.trip {
+                routeId = route.id
+                directionId = 0
+                stopIds =
+                    listOf(
+                        targetStop.id,
+                        downstreamStop1.id,
+                        downstreamStop2.id,
+                    )
+            }
+
+        val downstreamAlerts =
+            Alert.downstreamAlerts(
+                listOf(alertAllStops, alertDownstream2Only),
+                trip,
+                setOf(targetStop.id)
+            )
+
+        assertEquals(listOf(alertDownstream2Only), downstreamAlerts)
+    }
+
+
+
     @Test
     fun `downstreamAlerts ignores alert without stops specified`() {
         val objects = ObjectCollectionBuilder()

shared/src/commonTest/kotlin/com/mbta/tid/mbta_app/model/NearbyResponseTest.kt

@@ -3108,7 +3108,7 @@ class NearbyResponseTest {
                                         )
                                     ),
                                     alertsHere = listOf(alert),
-                                    alertsDownstream = listOf(alert),
+                                    alertsDownstream = emptyList(),
                                     hasSchedulesToday = false
                                 ),
                             )