test: add response_factory facility for body unit tests

Author: ashtum

CMakeLists.txt

@@ -176,7 +176,9 @@ function(boost_burl_setup_properties target)
 endfunction()
 
 if (BOOST_BURL_MRDOCS_BUILD)
-    file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/mrdocs.cpp" "#include <boost/burl.hpp>\n")
+    file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/mrdocs.cpp"
+        "#include <boost/burl.hpp>\n"
+        "#include <boost/burl/test/response_factory.hpp>\n")
     add_library(boost_burl_mrdocs "${CMAKE_CURRENT_BINARY_DIR}/mrdocs.cpp")
     boost_burl_setup_properties(boost_burl_mrdocs)
     target_compile_definitions(boost_burl_mrdocs PUBLIC BOOST_BURL_MRDOCS)

doc/mrdocs.yml

@@ -10,6 +10,7 @@ file-patterns:
 # Filters
 include-symbols:
   - 'boost::burl::**'
+  - 'boost::burl::test::**'
 implementation-defined:
   - 'boost::burl::detail'
   - 'boost::burl::*::detail'

include/boost/burl/detail/connection_pool.hpp

@@ -11,6 +11,7 @@
 #define BOOST_BURL_DETAIL_CONNECTION_POOL_HPP
 
 #include <boost/burl/detail/config.hpp>
+#include <boost/burl/test/response_factory_fwd.hpp>
 #include <boost/capy/buffers.hpp>
 #include <boost/capy/detail/buffer_array.hpp>
 #include <boost/capy/io_task.hpp>
@@ -74,6 +75,7 @@ class connection
 class pooled_connection
 {
     friend class connection_pool;
+    friend class test::response_factory;
 
     using duration = std::chrono::steady_clock::duration;
 

include/boost/burl/response.hpp

@@ -14,6 +14,7 @@
 #include <boost/burl/detail/config.hpp>
 #include <boost/burl/detail/connection_pool.hpp>
 #include <boost/burl/error.hpp>
+#include <boost/burl/test/response_factory_fwd.hpp>
 #include <boost/capy/io/any_buffer_source.hpp>
 #include <boost/capy/io/any_read_source.hpp>
 #include <boost/capy/io_task.hpp>
@@ -74,13 +75,15 @@ namespace burl
 class response
 {
     friend class client;
+    friend class test::response_factory;
     using clock = std::chrono::steady_clock;
 
     urls::url url_;
     detail::pooled_connection conn_;
     http::response_parser parser_;
     std::optional<clock::time_point> deadline_;
 
+    BOOST_BURL_DECL
     response(
         urls::url url,
         detail::pooled_connection conn,

include/boost/burl/test/detail/buffer_connection.hpp

@@ -0,0 +1,97 @@
+//
+// Copyright (c) 2026 Mohammad Nejati
+//
+// 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)
+//
+// Official repository: https://github.com/cppalliance/burl
+//
+
+#ifndef BOOST_BURL_TEST_DETAIL_BUFFER_CONNECTION_HPP
+#define BOOST_BURL_TEST_DETAIL_BUFFER_CONNECTION_HPP
+
+#include <boost/burl/detail/connection_pool.hpp>
+
+#include <boost/capy/buffers/buffer_copy.hpp>
+#include <boost/capy/buffers/make_buffer.hpp>
+#include <boost/capy/error.hpp>
+#include <boost/capy/io_task.hpp>
+#include <boost/capy/test/fuse.hpp>
+#include <boost/capy/buffers/buffer_slice.hpp>
+
+#include <cstddef>
+#include <string>
+#include <vector>
+
+namespace boost
+{
+namespace burl
+{
+namespace test
+{
+namespace detail
+{
+
+class buffer_connection final : public burl::detail::connection
+{
+    std::vector<std::string> chunks_;
+    capy::test::fuse fuse_;
+    std::size_t idx_ = 0;
+    std::size_t pos_ = 0;
+
+public:
+    buffer_connection(
+        std::vector<std::string> chunks,
+        capy::test::fuse fuse)
+        : chunks_(std::move(chunks))
+        , fuse_(std::move(fuse))
+    {
+    }
+
+    bool
+    is_open() const noexcept override
+    {
+        return true;
+    }
+
+    capy::io_task<>
+    shutdown() override
+    {
+        co_return {};
+    }
+
+private:
+    capy::io_task<std::size_t>
+    do_read_some(std::span<capy::mutable_buffer const> bufs) override
+    {
+        if(auto ec = fuse_.maybe_fail())
+            co_return { ec, 0 };
+
+        if(idx_ >= chunks_.size())
+            co_return { capy::error::eof, 0 };
+
+        auto const b = capy::make_buffer(chunks_[idx_]);
+        auto const n = capy::buffer_copy(
+            bufs, capy::buffer_slice(b, pos_).data());
+        pos_ += n;
+        if(pos_ == b.size())
+        {
+            ++idx_;
+            pos_ = 0;
+        }
+        co_return { {}, n };
+    }
+
+    capy::io_task<std::size_t>
+    do_write_some(std::span<capy::const_buffer const>) override
+    {
+        co_return { capy::error::eof, 0 };
+    }
+};
+
+} // namespace detail
+} // namespace test
+} // namespace burl
+} // namespace boost
+
+#endif