message: Added BLOB tests for NULL and empty values.
diff: using namespace duckdb;
  using namespace std;
  +TEST_CASE("BLOB null and empty values", "[blob]") {
  + unique_ptr<QueryResult> result;
  + DuckDB db(nullptr);
  + Connection con(db);
  + result = con.Query("SELECT ''::BLOB");
  + REQUIRE(CHECK_COLUMN(result, 0, {""}));
  +
  + result = con.Query("SELECT NULL::BLOB");
  + REQUIRE(CHECK_COLUMN(result, 0, {Value(nullptr)}));
  +
  + REQUIRE_NO_FAIL(con.Query("CREATE TABLE blobs (b BYTEA);"));
  + REQUIRE_NO_FAIL(con.Query("INSERT INTO blobs VALUES(''), (''::BLOB)"));
  + REQUIRE_NO_FAIL(con.Query("INSERT INTO blobs VALUES(NULL), (NULL::BLOB)"));
  +
  + result = con.Query("SELECT * FROM blobs");
  + REQUIRE(CHECK_COLUMN(result, 0, {"", "", Value(nullptr), Value(nullptr)}));
  +}
  +
  TEST_CASE("Cast BLOB values", "[blob]") {
  unique_ptr<QueryResult> result;
  DuckDB db(nullptr);
  