test(persistence): cover the v29 feed-clearing migration

Folds in the standalone migration work from #1284, which duplicated the
28 -> 29 clear this branch already carries.

Adds TransactionHistoryMigrationTest, following the hand-rolled pattern
in UserProfileMigrationTest: asserts the feed is emptied, that a
neighbouring table survives, and that it's a no-op on an already-empty
feed.

Also switches Migration28To29 to the onPostMigrate(SQLiteConnection)
overload. Room's SupportSQLiteDatabase variant only fires when the
database is built without a driver, so a future setDriver would turn the
delete into a silent no-op.

Author: bmc08gt

apps/flipcash/shared/persistence/db/src/main/kotlin/com/flipcash/app/persistence/FlipcashDatabase.kt

@@ -10,7 +10,9 @@ import androidx.room.RoomDatabase
 import androidx.room.TypeConverters
 import androidx.room.migration.AutoMigrationSpec
 import androidx.room.migration.Migration
+import androidx.sqlite.SQLiteConnection
 import androidx.sqlite.db.SupportSQLiteDatabase
+import androidx.sqlite.execSQL
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.asStateFlow
@@ -199,10 +201,14 @@ abstract class FlipcashDatabase : RoomDatabase() {
      * Clearing the cache is the repair. The next sync sees an empty table, falls into its
      * descending re-seed, and re-fetches the recent feed from scratch; paging refills older
      * history on demand.
+     *
+     * Takes the [SQLiteConnection] overload rather than the [SupportSQLiteDatabase] one used by
+     * [Migration22To23]: the latter only fires when Room is built without a driver, so a future
+     * `setDriver` would turn the delete into a silent no-op.
      */
     class Migration28To29 : AutoMigrationSpec {
-        override fun onPostMigrate(db: SupportSQLiteDatabase) {
-            db.execSQL("DELETE FROM messages")
+        override fun onPostMigrate(connection: SQLiteConnection) {
+            connection.execSQL("DELETE FROM messages")
         }
     }
 

apps/flipcash/shared/persistence/db/src/test/kotlin/com/flipcash/app/persistence/TransactionHistoryMigrationTest.kt

@@ -0,0 +1,85 @@
+package com.flipcash.app.persistence
+
+import android.content.Context
+import androidx.sqlite.db.SupportSQLiteDatabase
+import androidx.sqlite.db.SupportSQLiteOpenHelper
+import androidx.sqlite.db.framework.FrameworkSQLiteOpenHelperFactory
+import androidx.sqlite.driver.SupportSQLiteConnection
+import androidx.test.core.app.ApplicationProvider
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.robolectric.RobolectricTestRunner
+import kotlin.test.assertEquals
+
+/**
+ * Covers the v29 upgrade dropping the cached transaction history.
+ *
+ * The feed is a re-fetchable cache ([FlipcashDatabase.Migration28To29]), so the contract is simply
+ * "after the upgrade, `messages` is empty and every other table is untouched".
+ */
+@RunWith(RobolectricTestRunner::class)
+class TransactionHistoryMigrationTest {
+
+    private val context = ApplicationProvider.getApplicationContext<Context>()
+
+    private fun openV28Database(): SupportSQLiteDatabase {
+        val callback = object : SupportSQLiteOpenHelper.Callback(1) {
+            override fun onCreate(db: SupportSQLiteDatabase) = Unit
+            override fun onUpgrade(db: SupportSQLiteDatabase, oldVersion: Int, newVersion: Int) = Unit
+        }
+        val config = SupportSQLiteOpenHelper.Configuration.builder(context)
+            .name(null) // in-memory
+            .callback(callback)
+            .build()
+        val db = FrameworkSQLiteOpenHelperFactory().create(config).writableDatabase
+        db.execSQL(
+            "CREATE TABLE messages (idBase58 TEXT NOT NULL, text TEXT NOT NULL, " +
+                "amountUsdc INTEGER, amountNative INTEGER, nativeCurrency TEXT, rate REAL, " +
+                "state TEXT NOT NULL, timestamp INTEGER NOT NULL, metadata TEXT, " +
+                "mintBase58 TEXT DEFAULT 'EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v', " +
+                "text_substitutions TEXT, PRIMARY KEY(idBase58))"
+        )
+        // A neighbouring table, to pin down that the migration only clears the feed.
+        db.execSQL(
+            "CREATE TABLE blocked_users (user_id_hex TEXT NOT NULL, " +
+                "blocked_at_epoch_ms INTEGER NOT NULL, PRIMARY KEY(user_id_hex))"
+        )
+        return db
+    }
+
+    private fun SupportSQLiteDatabase.count(table: String): Int =
+        query("SELECT COUNT(*) FROM $table").use { it.moveToFirst(); it.getInt(0) }
+
+    private fun SupportSQLiteDatabase.insertMessage(id: String, timestamp: Long) = execSQL(
+        "INSERT INTO messages (idBase58, text, state, timestamp) VALUES (?,?,?,?)",
+        arrayOf<Any?>(id, "sent \$1.00", "COMPLETED", timestamp),
+    )
+
+    @Test
+    fun `migration 28 to 29 drops the cached transaction history`() {
+        val db = openV28Database()
+        db.insertMessage("msgA", 1L)
+        db.insertMessage("msgB", 2L)
+        db.execSQL("INSERT INTO blocked_users VALUES (?,?)", arrayOf<Any?>("u1", 111L))
+        assertEquals(2, db.count("messages"))
+
+        FlipcashDatabase.Migration28To29().onPostMigrate(SupportSQLiteConnection(db))
+
+        assertEquals(0, db.count("messages"))
+        // Only the feed is cleared — unrelated caches survive the upgrade.
+        assertEquals(1, db.count("blocked_users"))
+
+        db.close()
+    }
+
+    @Test
+    fun `migration 28 to 29 is a no-op on an already-empty feed`() {
+        val db = openV28Database()
+
+        FlipcashDatabase.Migration28To29().onPostMigrate(SupportSQLiteConnection(db))
+
+        assertEquals(0, db.count("messages"))
+
+        db.close()
+    }
+}