Fixes std::tuple serialization and adds tests (#363)

* Fixes a problem that caused passing ranges containing tuples into `request::push_range` to generate invalid commands.
* Adds test_serialization
* Updates request reference docs to reflect the requirements of the types passed to push and push_range

close #360

test/CMakeLists.txt

@@ -35,6 +35,7 @@ endmacro()
 # Unit tests
 make_test(test_low_level)
 make_test(test_request)
+make_test(test_serialization)
 make_test(test_low_level_sync_sans_io)
 make_test(test_any_adapter)
 make_test(test_log_to_file)

test/Jamfile

@@ -52,6 +52,7 @@ lib redis_test_common
 local tests =
     test_low_level
     test_request
+    test_serialization
     test_low_level_sync_sans_io
     test_any_adapter
     test_log_to_file

test/test_request.cpp

@@ -14,8 +14,6 @@
 
 using boost::redis::request;
 
-// TODO: Serialization.
-
 namespace {
 
 void test_push_no_args()

test/test_serialization.cpp

@@ -0,0 +1,193 @@
+//
+// Copyright (c) 2025 Marcelo Zimbres Silva (mzimbres@gmail.com),
+// Ruben Perez Hidalgo (rubenperez038 at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#include <boost/redis/request.hpp>
+#include <boost/redis/resp3/serialization.hpp>
+
+#include <boost/core/lightweight_test.hpp>
+
+#include <cstdint>
+#include <limits>
+#include <string>
+#include <string_view>
+#include <utility>
+#include <vector>
+
+using boost::redis::request;
+
+namespace other {
+
+struct my_struct {
+   int value;
+};
+
+void boost_redis_to_bulk(std::string& to, my_struct value)
+{
+   boost::redis::resp3::boost_redis_to_bulk(to, value.value);
+}
+
+}  // namespace other
+
+namespace {
+
+// --- Strings ---
+void test_string_view()
+{
+   request req;
+   req.push("GET", std::string_view("key"));
+   BOOST_TEST_EQ(req.payload(), "*2\r\n$3\r\nGET\r\n$3\r\nkey\r\n");
+}
+
+void test_string()
+{
+   std::string s{"k1"};
+   const std::string s2{"k2"};
+   request req;
+   req.push("GET", s, s2, std::string("k3"));
+   BOOST_TEST_EQ(req.payload(), "*4\r\n$3\r\nGET\r\n$2\r\nk1\r\n$2\r\nk2\r\n$2\r\nk3\r\n");
+}
+
+void test_c_string()
+{
+   request req;
+   req.push("GET", "k1", static_cast<const char*>("k2"));
+   BOOST_TEST_EQ(req.payload(), "*3\r\n$3\r\nGET\r\n$2\r\nk1\r\n$2\r\nk2\r\n");
+}
+
+void test_string_empty()
+{
+   request req;
+   req.push("GET", std::string_view{});
+   BOOST_TEST_EQ(req.payload(), "*2\r\n$3\r\nGET\r\n$0\r\n\r\n");
+}
+
+// --- Integers ---
+void test_signed_ints()
+{
+   request req;
+   req.push("GET", static_cast<signed char>(20), static_cast<short>(-42), -1, 80l, 200ll);
+   BOOST_TEST_EQ(
+      req.payload(),
+      "*6\r\n$3\r\nGET\r\n$2\r\n20\r\n$3\r\n-42\r\n$2\r\n-1\r\n$2\r\n80\r\n$3\r\n200\r\n");
+}
+
+void test_unsigned_ints()
+{
+   request req;
+   req.push(
+      "GET",
+      static_cast<unsigned char>(20),
+      static_cast<unsigned short>(42),
+      50u,
+      80ul,
+      200ull);
+   BOOST_TEST_EQ(
+      req.payload(),
+      "*6\r\n$3\r\nGET\r\n$2\r\n20\r\n$2\r\n42\r\n$2\r\n50\r\n$2\r\n80\r\n$3\r\n200\r\n");
+}
+
+// We don't overflow for big ints
+void test_signed_ints_minmax()
+{
+   using lims = std::numeric_limits<std::int64_t>;
+   request req;
+   req.push("GET", (lims::min)(), (lims::max)());
+   BOOST_TEST_EQ(
+      req.payload(),
+      "*3\r\n$3\r\nGET\r\n$20\r\n-9223372036854775808\r\n$19\r\n9223372036854775807\r\n");
+}
+
+void test_unsigned_ints_max()
+{
+   request req;
+   req.push("GET", (std::numeric_limits<std::uint64_t>::max)());
+   BOOST_TEST_EQ(req.payload(), "*2\r\n$3\r\nGET\r\n$20\r\n18446744073709551615\r\n");
+}
+
+// Custom type
+void test_custom()
+{
+   request req;
+   req.push("GET", other::my_struct{42});
+   BOOST_TEST_EQ(req.payload(), "*2\r\n$3\r\nGET\r\n$2\r\n42\r\n");
+}
+
+// --- Pairs and tuples (only supported in the range versions) ---
+// Nested structures are not supported (compile time error)
+void test_pair()
+{
+   std::vector<std::pair<std::string_view, int>> vec{
+      {"k1", 42}
+   };
+   request req;
+   req.push_range("GET", vec);
+   BOOST_TEST_EQ(req.payload(), "*3\r\n$3\r\nGET\r\n$2\r\nk1\r\n$2\r\n42\r\n");
+}
+
+void test_pair_custom()
+{
+   std::vector<std::pair<std::string_view, other::my_struct>> vec{
+      {"k1", {42}}
+   };
+   request req;
+   req.push_range("GET", vec);
+   BOOST_TEST_EQ(req.payload(), "*3\r\n$3\r\nGET\r\n$2\r\nk1\r\n$2\r\n42\r\n");
+}
+
+void test_tuple()
+{
+   std::vector<std::tuple<std::string_view, int, unsigned char>> vec{
+      {"k1", 42, 1}
+   };
+   request req;
+   req.push_range("GET", vec);
+   BOOST_TEST_EQ(req.payload(), "*4\r\n$3\r\nGET\r\n$2\r\nk1\r\n$2\r\n42\r\n$1\r\n1\r\n");
+}
+
+void test_tuple_custom()
+{
+   std::vector<std::tuple<std::string_view, other::my_struct>> vec{
+      {"k1", {42}}
+   };
+   request req;
+   req.push_range("GET", vec);
+   BOOST_TEST_EQ(req.payload(), "*3\r\n$3\r\nGET\r\n$2\r\nk1\r\n$2\r\n42\r\n");
+}
+
+void test_tuple_empty()
+{
+   std::vector<std::tuple<>> vec{{}};
+   request req;
+   req.push_range("GET", vec);
+   BOOST_TEST_EQ(req.payload(), "*1\r\n$3\r\nGET\r\n");
+}
+
+}  // namespace
+
+int main()
+{
+   test_string_view();
+   test_string();
+   test_c_string();
+   test_string_empty();
+
+   test_signed_ints();
+   test_unsigned_ints();
+   test_signed_ints_minmax();
+   test_unsigned_ints_max();
+
+   test_custom();
+
+   test_pair();
+   test_pair_custom();
+   test_tuple();
+   test_tuple_custom();
+   test_tuple_empty();
+
+   return boost::report_errors();
+}