feat(safety): log wind and current conditions at MOB activation (Section 4.6)

Per COMPONENT_DESIGN.md Section 4.6, the MOB navigation view must display
wind and current conditions at the time of the event.

- MobEvent: add nullable windSpeedKt, windDirectionDeg, currentSpeedKt,
  currentDirectionDeg fields captured at the exact moment of activation
- MobAlarmManager.activate(): accept optional wind/current params and
  forward them into MobEvent (defaults to null for backward compatibility)
- LocationService (new): aggregates live SensorData (resolves true wind via
  TrueWindCalculator) and marine-forecast current conditions; snapshot()
  provides a point-in-time EnvironmentalSnapshot for safety-critical logging
- MobAlarmManagerTest: add tests for wind/current storage and null defaults
- LocationServiceTest (new): covers snapshot, true-wind resolution,
  current-condition updates, and the latestSensor flow

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

1 files changed, 117 insertions, 0 deletions

diff --git a/android-app/app/src/test/kotlin/com/example/androidapp/gps/LocationServiceTest.kt b/android-app/app/src/test/kotlin/com/example/androidapp/gps/LocationServiceTest.kt
new file mode 100644
index 0000000..d9192c6
--- /dev/null
+++ b/android-app/app/src/test/kotlin/com/example/androidapp/gps/LocationServiceTest.kt
@@ -0,0 +1,117 @@
+package com.example.androidapp.gps
+
+import com.example.androidapp.data.model.SensorData
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.runBlocking
+import org.junit.Assert.*
+import org.junit.Test
+
+class LocationServiceTest {
+
+    private fun service() = LocationService()
+
+    // ── snapshot with no data ─────────────────────────────────────────────────
+
+    @Test
+    fun snapshot_noData_allFieldsNull() {
+        val snap = service().snapshot()
+        assertNull(snap.windSpeedKt)
+        assertNull(snap.windDirectionDeg)
+        assertNull(snap.currentSpeedKt)
+        assertNull(snap.currentDirectionDeg)
+    }
+
+    // ── true-wind resolution ──────────────────────────────────────────────────
+
+    @Test
+    fun updateSensorData_withFullReading_resolvesTrueWind() = runBlocking {
+        val svc = service()
+        // Head north (hdg = 0°), AWS = 10 kt coming from ahead (AWA = 0°), BSP = 5 kt
+        // → TW comes FROM ahead at 5 kt
+        svc.updateSensorData(
+            SensorData(
+                headingTrueDeg = 0.0,
+                apparentWindSpeedKt = 10.0,
+                apparentWindAngleDeg = 0.0,
+                speedOverGroundKt = 5.0
+            )
+        )
+        val tw = svc.latestTrueWind.first()
+        assertNotNull(tw)
+        assertTrue("Expected TWS > 0", tw!!.speedKt > 0.0)
+    }
+
+    @Test
+    fun updateSensorData_missingHeading_doesNotResolveTrueWind() = runBlocking {
+        val svc = service()
+        svc.updateSensorData(
+            SensorData(
+                apparentWindSpeedKt = 10.0,
+                apparentWindAngleDeg = 45.0,
+                speedOverGroundKt = 5.0
+                // headingTrueDeg omitted
+            )
+        )
+        assertNull(svc.latestTrueWind.first())
+    }
+
+    // ── current conditions ────────────────────────────────────────────────────
+
+    @Test
+    fun updateCurrentConditions_reflectedInSnapshot() {
+        val svc = service()
+        svc.updateCurrentConditions(speedKt = 1.5, directionDeg = 135.0)
+
+        val snap = svc.snapshot()
+        assertEquals(1.5, snap.currentSpeedKt!!, 0.001)
+        assertEquals(135.0, snap.currentDirectionDeg!!, 0.001)
+    }
+
+    @Test
+    fun updateCurrentConditions_nullClears() {
+        val svc = service()
+        svc.updateCurrentConditions(speedKt = 2.0, directionDeg = 90.0)
+        svc.updateCurrentConditions(speedKt = null, directionDeg = null)
+
+        val snap = svc.snapshot()
+        assertNull(snap.currentSpeedKt)
+        assertNull(snap.currentDirectionDeg)
+    }
+
+    // ── combined snapshot ─────────────────────────────────────────────────────
+
+    @Test
+    fun snapshot_afterFullUpdate_populatesAllFields() = runBlocking {
+        val svc = service()
+
+        // Head east (hdg = 90°), wind from starboard bow, BSP proxy = 6 kt
+        svc.updateSensorData(
+            SensorData(
+                headingTrueDeg = 90.0,
+                apparentWindSpeedKt = 12.0,
+                apparentWindAngleDeg = 45.0,
+                speedOverGroundKt = 6.0
+            )
+        )
+        svc.updateCurrentConditions(speedKt = 0.8, directionDeg = 270.0)
+
+        val snap = svc.snapshot()
+        assertNotNull(snap.windSpeedKt)
+        assertNotNull(snap.windDirectionDeg)
+        assertEquals(0.8, snap.currentSpeedKt!!, 0.001)
+        assertEquals(270.0, snap.currentDirectionDeg!!, 0.001)
+    }
+
+    // ── latestSensor flow ─────────────────────────────────────────────────────
+
+    @Test
+    fun updateSensorData_updatesLatestSensorFlow() = runBlocking {
+        val svc = service()
+        assertNull(svc.latestSensor.first())
+
+        val data = SensorData(latitude = 41.5, longitude = -71.3)
+        svc.updateSensorData(data)
+
+        assertEquals(data, svc.latestSensor.first())
+    }
+}