diff --git a/test/Jamfile.v2 b/test/Jamfile.v2
index 6b179e1..bf59485 100644
--- a/test/Jamfile.v2
+++ b/test/Jamfile.v2
@@ -252,6 +252,7 @@ run sv_construct_test.cpp ;
 run sv_element_access_test.cpp ;
 run sv_modifiers_test.cpp ;
 run sv_copy_test.cpp ;
+run sv_substr_test.cpp ;
 
 use-project /boost/core/swap : ./swap ;
 build-project ./swap ;
diff --git a/test/sv_substr_test.cpp b/test/sv_substr_test.cpp
new file mode 100644
index 0000000..666aebf
--- /dev/null
+++ b/test/sv_substr_test.cpp
@@ -0,0 +1,203 @@
+// 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>
+#include <cstddef>
+
+int main()
+{
+    {
+        boost::core::string_view sv;
+
+        {
+            boost::core::string_view sv2 = sv.substr();
+
+            BOOST_TEST_EQ( sv2.data(), sv.data() );
+            BOOST_TEST_EQ( sv2.size(), sv.size() );
+        }
+
+        {
+            boost::core::string_view sv2 = sv.substr( 0 );
+
+            BOOST_TEST_EQ( sv2.data(), sv.data() );
+            BOOST_TEST_EQ( sv2.size(), sv.size() );
+        }
+
+        BOOST_TEST_THROWS( sv.substr( 1 ), std::out_of_range );
+        BOOST_TEST_THROWS( sv.substr( boost::core::string_view::npos ), std::out_of_range );
+
+        {
+            boost::core::string_view sv2 = sv.substr( 0, 1 );
+
+            BOOST_TEST_EQ( sv2.data(), sv.data() );
+            BOOST_TEST_EQ( sv2.size(), sv.size() );
+        }
+
+        {
+            boost::core::string_view sv2 = sv.substr( 0, 0 );
+
+            BOOST_TEST_EQ( sv2.data(), sv.data() );
+            BOOST_TEST_EQ( sv2.size(), sv.size() );
+        }
+
+        BOOST_TEST_THROWS( sv.substr( 1, 0 ), std::out_of_range );
+        BOOST_TEST_THROWS( sv.substr( boost::core::string_view::npos, 0 ), std::out_of_range );
+    }
+
+    {
+        boost::core::string_view sv( "12345" );
+
+        {
+            boost::core::string_view sv2 = sv.substr();
+
+            BOOST_TEST_EQ( sv2.data(), sv.data() );
+            BOOST_TEST_EQ( sv2.size(), sv.size() );
+        }
+
+        {
+            boost::core::string_view sv2 = sv.substr( 0 );
+
+            BOOST_TEST_EQ( sv2.data(), sv.data() );
+            BOOST_TEST_EQ( sv2.size(), sv.size() );
+        }
+
+        {
+            boost::core::string_view sv2 = sv.substr( 2 );
+
+            BOOST_TEST_EQ( sv2.data(), sv.data() + 2 );
+            BOOST_TEST_EQ( sv2.size(), sv.size() - 2 );
+        }
+
+        {
+            boost::core::string_view sv2 = sv.substr( 5 );
+
+            BOOST_TEST_EQ( sv2.data(), sv.data() + 5 );
+            BOOST_TEST_EQ( sv2.size(), sv.size() - 5 );
+        }
+
+        BOOST_TEST_THROWS( sv.substr( 6 ), std::out_of_range );
+        BOOST_TEST_THROWS( sv.substr( boost::core::string_view::npos ), std::out_of_range );
+
+        {
+            boost::core::string_view sv2 = sv.substr( 0, 0 );
+
+            BOOST_TEST_EQ( sv2.data(), sv.data() );
+            BOOST_TEST_EQ( sv2.size(), 0 );
+        }
+
+        {
+            boost::core::string_view sv2 = sv.substr( 2, 0 );
+
+            BOOST_TEST_EQ( sv2.data(), sv.data() + 2 );
+            BOOST_TEST_EQ( sv2.size(), 0 );
+        }
+
+        {
+            boost::core::string_view sv2 = sv.substr( 5, 0 );
+
+            BOOST_TEST_EQ( sv2.data(), sv.data() + 5 );
+            BOOST_TEST_EQ( sv2.size(), 0 );
+        }
+
+        BOOST_TEST_THROWS( sv.substr( 6, 0 ), std::out_of_range );
+        BOOST_TEST_THROWS( sv.substr( boost::core::string_view::npos, 0 ), std::out_of_range );
+
+        {
+            boost::core::string_view sv2 = sv.substr( 0, 3 );
+
+            BOOST_TEST_EQ( sv2.data(), sv.data() );
+            BOOST_TEST_EQ( sv2.size(), 3 );
+        }
+
+        {
+            boost::core::string_view sv2 = sv.substr( 2, 3 );
+
+            BOOST_TEST_EQ( sv2.data(), sv.data() + 2 );
+            BOOST_TEST_EQ( sv2.size(), 3 );
+        }
+
+        {
+            boost::core::string_view sv2 = sv.substr( 4, 3 );
+
+            BOOST_TEST_EQ( sv2.data(), sv.data() + 4 );
+            BOOST_TEST_EQ( sv2.size(), 1 );
+        }
+
+        {
+            boost::core::string_view sv2 = sv.substr( 5, 3 );
+
+            BOOST_TEST_EQ( sv2.data(), sv.data() + 5 );
+            BOOST_TEST_EQ( sv2.size(), 0 );
+        }
+
+        BOOST_TEST_THROWS( sv.substr( 6, 3 ), std::out_of_range );
+        BOOST_TEST_THROWS( sv.substr( boost::core::string_view::npos, 3 ), std::out_of_range );
+
+        {
+            boost::core::string_view sv2 = sv.substr( 0, 5 );
+
+            BOOST_TEST_EQ( sv2.data(), sv.data() );
+            BOOST_TEST_EQ( sv2.size(), 5 );
+        }
+
+        {
+            boost::core::string_view sv2 = sv.substr( 2, 5 );
+
+            BOOST_TEST_EQ( sv2.data(), sv.data() + 2 );
+            BOOST_TEST_EQ( sv2.size(), 3 );
+        }
+
+        {
+            boost::core::string_view sv2 = sv.substr( 4, 5 );
+
+            BOOST_TEST_EQ( sv2.data(), sv.data() + 4 );
+            BOOST_TEST_EQ( sv2.size(), 1 );
+        }
+
+        {
+            boost::core::string_view sv2 = sv.substr( 5, 5 );
+
+            BOOST_TEST_EQ( sv2.data(), sv.data() + 5 );
+            BOOST_TEST_EQ( sv2.size(), 0 );
+        }
+
+        BOOST_TEST_THROWS( sv.substr( 6, 5 ), std::out_of_range );
+        BOOST_TEST_THROWS( sv.substr( boost::core::string_view::npos, 5 ), std::out_of_range );
+
+        {
+            boost::core::string_view sv2 = sv.substr( 0, 8 );
+
+            BOOST_TEST_EQ( sv2.data(), sv.data() );
+            BOOST_TEST_EQ( sv2.size(), 5 );
+        }
+
+        {
+            boost::core::string_view sv2 = sv.substr( 2, 8 );
+
+            BOOST_TEST_EQ( sv2.data(), sv.data() + 2 );
+            BOOST_TEST_EQ( sv2.size(), 3 );
+        }
+
+        {
+            boost::core::string_view sv2 = sv.substr( 4, 8 );
+
+            BOOST_TEST_EQ( sv2.data(), sv.data() + 4 );
+            BOOST_TEST_EQ( sv2.size(), 1 );
+        }
+
+        {
+            boost::core::string_view sv2 = sv.substr( 5, 8 );
+
+            BOOST_TEST_EQ( sv2.data(), sv.data() + 5 );
+            BOOST_TEST_EQ( sv2.size(), 0 );
+        }
+
+        BOOST_TEST_THROWS( sv.substr( 6, 8 ), std::out_of_range );
+        BOOST_TEST_THROWS( sv.substr( boost::core::string_view::npos, 8 ), std::out_of_range );
+    }
+
+    return boost::report_errors();
+}