diff --git a/test/sv_find_first_of_test.cpp b/test/sv_find_first_of_test.cpp
index 92e4188..728d4f6 100644
--- a/test/sv_find_first_of_test.cpp
+++ b/test/sv_find_first_of_test.cpp
@@ -305,6 +305,46 @@ int main()
         BOOST_TEST_EQ( sv.find_first_of( L"123", 7, 3 ), npos );
     }
 
+    {
+        boost::core::wstring_view sv( L"\x101\x102\x103\x101\x102\x103" );
+
+        BOOST_TEST_EQ( sv.find_first_of( L"\x101\x102\x103", 0, 0 ), npos );
+        BOOST_TEST_EQ( sv.find_first_of( L"\x101\x102\x103", 1, 0 ), npos );
+        BOOST_TEST_EQ( sv.find_first_of( L"\x101\x102\x103", 2, 0 ), npos );
+        BOOST_TEST_EQ( sv.find_first_of( L"\x101\x102\x103", 3, 0 ), npos );
+        BOOST_TEST_EQ( sv.find_first_of( L"\x101\x102\x103", 4, 0 ), npos );
+        BOOST_TEST_EQ( sv.find_first_of( L"\x101\x102\x103", 5, 0 ), npos );
+        BOOST_TEST_EQ( sv.find_first_of( L"\x101\x102\x103", 6, 0 ), npos );
+        BOOST_TEST_EQ( sv.find_first_of( L"\x101\x102\x103", 7, 0 ), npos );
+
+        BOOST_TEST_EQ( sv.find_first_of( L"\x101\x102\x103", 0, 1 ), 0 );
+        BOOST_TEST_EQ( sv.find_first_of( L"\x101\x102\x103", 1, 1 ), 3 );
+        BOOST_TEST_EQ( sv.find_first_of( L"\x101\x102\x103", 2, 1 ), 3 );
+        BOOST_TEST_EQ( sv.find_first_of( L"\x101\x102\x103", 3, 1 ), 3 );
+        BOOST_TEST_EQ( sv.find_first_of( L"\x101\x102\x103", 4, 1 ), npos );
+        BOOST_TEST_EQ( sv.find_first_of( L"\x101\x102\x103", 5, 1 ), npos );
+        BOOST_TEST_EQ( sv.find_first_of( L"\x101\x102\x103", 6, 1 ), npos );
+        BOOST_TEST_EQ( sv.find_first_of( L"\x101\x102\x103", 7, 1 ), npos );
+
+        BOOST_TEST_EQ( sv.find_first_of( L"\x101\x102\x103", 0, 2 ), 0 );
+        BOOST_TEST_EQ( sv.find_first_of( L"\x101\x102\x103", 1, 2 ), 1 );
+        BOOST_TEST_EQ( sv.find_first_of( L"\x101\x102\x103", 2, 2 ), 3 );
+        BOOST_TEST_EQ( sv.find_first_of( L"\x101\x102\x103", 3, 2 ), 3 );
+        BOOST_TEST_EQ( sv.find_first_of( L"\x101\x102\x103", 4, 2 ), 4 );
+        BOOST_TEST_EQ( sv.find_first_of( L"\x101\x102\x103", 5, 2 ), npos );
+        BOOST_TEST_EQ( sv.find_first_of( L"\x101\x102\x103", 6, 2 ), npos );
+        BOOST_TEST_EQ( sv.find_first_of( L"\x101\x102\x103", 7, 2 ), npos );
+
+        BOOST_TEST_EQ( sv.find_first_of( L"\x101\x102\x103", 0, 3 ), 0 );
+        BOOST_TEST_EQ( sv.find_first_of( L"\x101\x102\x103", 1, 3 ), 1 );
+        BOOST_TEST_EQ( sv.find_first_of( L"\x101\x102\x103", 2, 3 ), 2 );
+        BOOST_TEST_EQ( sv.find_first_of( L"\x101\x102\x103", 3, 3 ), 3 );
+        BOOST_TEST_EQ( sv.find_first_of( L"\x101\x102\x103", 4, 3 ), 4 );
+        BOOST_TEST_EQ( sv.find_first_of( L"\x101\x102\x103", 5, 3 ), 5 );
+        BOOST_TEST_EQ( sv.find_first_of( L"\x101\x102\x103", 6, 3 ), npos );
+        BOOST_TEST_EQ( sv.find_first_of( L"\x101\x102\x103", 7, 3 ), npos );
+    }
+
     {
         boost::core::string_view sv( "abc1abc2abc3" );