Revert removal of deprecated lowest_layer from test::stream:

This reverts commit 3fb693eda6.

CHANGELOG.md

@@ -1,3 +1,7 @@
+* Revert removal of lowest_layer_type from test stream.
+
+--------------------------------------------------------------------------------
+
 Version 305:
 
 * Fix documentation build.

include/boost/beast/_experimental/test/stream.hpp

@@ -186,6 +186,27 @@ class stream
         std::unique_ptr<read_op_base>&& op,
         std::size_t buf_size);
 
+#if ! BOOST_BEAST_DOXYGEN
+    // boost::asio::ssl::stream needs these
+    // DEPRECATED
+    template<class>
+    friend class boost::asio::ssl::stream;
+    // DEPRECATED
+    using lowest_layer_type = stream;
+    // DEPRECATED
+    lowest_layer_type&
+    lowest_layer() noexcept
+    {
+        return *this;
+    }
+    // DEPRECATED
+    lowest_layer_type const&
+    lowest_layer() const noexcept
+    {
+        return *this;
+    }
+#endif
+
 public:
     using buffer_type = flat_buffer;
 

test/beast/_experimental/stream.cpp

@@ -13,6 +13,8 @@
 #include <boost/beast/_experimental/unit_test/suite.hpp>
 #include <boost/beast/_experimental/test/handler.hpp>
 
+#include <boost/asio/ssl/stream.hpp>
+
 namespace boost {
 namespace beast {
 
@@ -141,12 +143,23 @@ public:
         sp.reset();
     }
 
+    void
+    testAsioSSLCompat()
+    {
+        BOOST_STATIC_ASSERT(
+            std::is_same<
+                boost::asio::ssl::stream<test::stream>::
+                    lowest_layer_type,
+                test::stream>::value);
+    }
+
     void
     run() override
     {
         testTestStream();
         testSharedAbandon();
         //testLifetimeViolation();
+        boost::ignore_unused(&stream_test::testAsioSSLCompat);
     }
 };