should be it

external/duckdb/test/appender/test_appender_transactions.cpp

@@ -0,0 +1,39 @@
+#include "catch.hpp"
+#include "duckdb/main/appender.hpp"
+#include "test_helpers.hpp"
+
+#include <vector>
+
+using namespace duckdb;
+using namespace std;
+
+TEST_CASE("Test the way appenders interact with transactions", "[appender]") {
+	duckdb::unique_ptr<QueryResult> result;
+	DuckDB db(nullptr);
+	Connection con(db);
+
+	REQUIRE_NO_FAIL(con.Query("CREATE TABLE integers(i INTEGER PRIMARY KEY)"));
+
+	// begin a transaction manually
+	REQUIRE_NO_FAIL(con.Query("BEGIN TRANSACTION"));
+
+	// append a value to the table
+	Appender appender(con, "integers");
+
+	appender.BeginRow();
+	appender.Append<int32_t>(1);
+	appender.EndRow();
+
+	appender.Close();
+
+	// we can select the value now
+	result = con.Query("SELECT * FROM integers");
+	REQUIRE(CHECK_COLUMN(result, 0, {1}));
+
+	// rolling back cancels the transaction
+	REQUIRE_NO_FAIL(con.Query("ROLLBACK"));
+
+	// now the values are gone
+	result = con.Query("SELECT * FROM integers");
+	REQUIRE(CHECK_COLUMN(result, 0, {}));
+}