walletdb: Create a mock database of specific type

We may want to make a mock database of either SQLite or BDB, not just
whatever the compiled default is.

src/wallet/walletdb.cpp

@@ -1187,13 +1187,36 @@ std::unique_ptr<WalletDatabase> CreateDummyWalletDatabase()
 }
 
 /** Return object for accessing temporary in-memory database. */
+std::unique_ptr<WalletDatabase> CreateMockWalletDatabase(DatabaseOptions& options)
+{
+
+    std::optional<DatabaseFormat> format;
+    if (options.require_format) format = options.require_format;
+    if (!format) {
+#ifdef USE_BDB
+        format = DatabaseFormat::BERKELEY;
+#endif
+#ifdef USE_SQLITE
+        format = DatabaseFormat::SQLITE;
+#endif
+    }
+
+    if (format == DatabaseFormat::SQLITE) {
+#ifdef USE_SQLITE
+        return std::make_unique<SQLiteDatabase>("", "", options, true);
+#endif
+        assert(false);
+    }
+
+#ifdef USE_BDB
+    return std::make_unique<BerkeleyDatabase>(std::make_shared<BerkeleyEnvironment>(), "", options);
+#endif
+    assert(false);
+}
+
 std::unique_ptr<WalletDatabase> CreateMockWalletDatabase()
 {
     DatabaseOptions options;
-#ifdef USE_SQLITE
+    return CreateMockWalletDatabase(options);
-    return std::make_unique<SQLiteDatabase>("", "", options, true);
-#elif USE_BDB
-    return std::make_unique<BerkeleyDatabase>(std::make_shared<BerkeleyEnvironment>(), "", options);
-#endif
 }
 } // namespace wallet

src/wallet/walletdb.h

@@ -301,6 +301,7 @@ bool ReadKeyValue(CWallet* pwallet, CDataStream& ssKey, CDataStream& ssValue, st
 std::unique_ptr<WalletDatabase> CreateDummyWalletDatabase();
 
 /** Return object for accessing temporary in-memory database. */
+std::unique_ptr<WalletDatabase> CreateMockWalletDatabase(DatabaseOptions& options);
 std::unique_ptr<WalletDatabase> CreateMockWalletDatabase();
 } // namespace wallet