2 files changed, 99 insertions, 0 deletions
diff --git a/android-app/app/src/test/kotlin/org/terst/nav/data/model/GribFileTest.kt b/android-app/app/src/test/kotlin/org/terst/nav/data/model/GribFileTest.kt
new file mode 100644
index 0000000..ef8bf7f
--- /dev/null
+++ b/android-app/app/src/test/kotlin/org/terst/nav/data/model/GribFileTest.kt
@@ -0,0 +1,63 @@
+package org.terst.nav.data.model
+
+import org.junit.Assert.*
+import org.junit.Test
+import java.time.Instant
+
+class GribFileTest {
+
+    private val region = GribRegion(
+        name = "Test Region",
+        latMin = 40.0,
+        latMax = 60.0,
+        lonMin = -10.0,
+        lonMax = 10.0
+    )
+
+    private val modelRun = Instant.parse("2026-03-15T00:00:00Z")
+    private val downloadedAt = Instant.parse("2026-03-15T01:00:00Z")
+
+    private fun makeFile(forecastHours: Int = 48) = GribFile(
+        region = region,
+        modelRunTime = modelRun,
+        forecastHours = forecastHours,
+        downloadedAt = downloadedAt,
+        filePath = "/data/grib/test.grib2",
+        sizeBytes = 1_000_000L
+    )
+
+    @Test
+    fun `validUntil_equalsModelRunPlusForecastHours`() {
+        val file = makeFile(forecastHours = 48)
+        val expected = modelRun.plusSeconds(48L * 3600)
+        assertEquals(expected, file.validUntil())
+    }
+
+    @Test
+    fun `isStale_returnsFalse_whenNowBeforeValidUntil`() {
+        val file = makeFile(forecastHours = 48)
+        val now = modelRun.plusSeconds(24L * 3600) // 24h in, still 24h to go
+        assertFalse(file.isStale(now))
+    }
+
+    @Test
+    fun `isStale_returnsTrue_whenNowAfterValidUntil`() {
+        val file = makeFile(forecastHours = 48)
+        val now = modelRun.plusSeconds(49L * 3600) // 1h past expiry
+        assertTrue(file.isStale(now))
+    }
+
+    @Test
+    fun `isStale_returnsFalse_whenNowExactlyAtValidUntil`() {
+        val file = makeFile(forecastHours = 48)
+        val now = file.validUntil() // exactly at boundary — not yet stale
+        assertFalse(file.isStale(now))
+    }
+
+    @Test
+    fun `ageSeconds_computesElapsedTime`() {
+        val file = makeFile()
+        val now = downloadedAt.plusSeconds(3600) // 1h after download
+        assertEquals(3600L, file.ageSeconds(now))
+    }
+}
diff --git a/android-app/app/src/test/kotlin/org/terst/nav/data/model/GribRegionTest.kt b/android-app/app/src/test/kotlin/org/terst/nav/data/model/GribRegionTest.kt
new file mode 100644
index 0000000..a9a0334
--- /dev/null
+++ b/android-app/app/src/test/kotlin/org/terst/nav/data/model/GribRegionTest.kt
@@ -0,0 +1,36 @@
+package org.terst.nav.data.model
+
+import org.junit.Assert.*
+import org.junit.Test
+
+class GribRegionTest {
+
+    private val region = GribRegion(
+        name = "Test Region",
+        latMin = 40.0,
+        latMax = 60.0,
+        lonMin = -10.0,
+        lonMax = 10.0
+    )
+
+    @Test
+    fun `contains_returnsTrue_whenPointInsideBounds`() {
+        assertTrue(region.contains(50.0, 0.0))
+    }
+
+    @Test
+    fun `contains_returnsFalse_whenLatOutOfRange`() {
+        assertFalse(region.contains(70.0, 0.0))
+    }
+
+    @Test
+    fun `contains_returnsFalse_whenLonOutOfRange`() {
+        assertFalse(region.contains(50.0, 20.0))
+    }
+
+    @Test
+    fun `areaDegrees_computesCorrectly`() {
+        val area = region.areaDegrees()
+        assertEquals(400.0, area, 0.0001)
+    }
+}