Add sv_element_access_test

test/Jamfile.v2

@@ -249,6 +249,7 @@ run type_name_test.cpp ;
 
 run sv_types_test.cpp ;
 run sv_construct_test.cpp ;
+run sv_element_access_test.cpp ;
 
 use-project /boost/core/swap : ./swap ;
 build-project ./swap ;

test/sv_element_access_test.cpp

@@ -0,0 +1,41 @@
+// Copyright 2021 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/core/string_view.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <stdexcept>
+
+int main()
+{
+    {
+        boost::core::string_view sv( "12345" );
+
+        for( std::size_t i = 0; i < 5; ++i )
+        {
+            BOOST_TEST_EQ( &sv[ i ], sv.data() + i );
+            BOOST_TEST_EQ( &sv.at( i ), sv.data() + i );
+        }
+
+        BOOST_TEST_THROWS( sv.at( 5 ), std::out_of_range );
+        BOOST_TEST_THROWS( sv.at( boost::core::string_view::npos ), std::out_of_range );
+    }
+
+    {
+        boost::core::string_view sv;
+
+        BOOST_TEST_THROWS( sv.at( 0 ), std::out_of_range );
+        BOOST_TEST_THROWS( sv.at( 1 ), std::out_of_range );
+        BOOST_TEST_THROWS( sv.at( boost::core::string_view::npos ), std::out_of_range );
+    }
+
+    {
+        boost::core::string_view sv( "12345", 0 );
+
+        BOOST_TEST_THROWS( sv.at( 0 ), std::out_of_range );
+        BOOST_TEST_THROWS( sv.at( 1 ), std::out_of_range );
+        BOOST_TEST_THROWS( sv.at( boost::core::string_view::npos ), std::out_of_range );
+    }
+
+    return boost::report_errors();
+}