Verify that custom iterator traits work correctly

test/compile_fail.hpp

@@ -0,0 +1,49 @@
+#include <fstream>
+
+#include <streambuf>
+
+#include <boost/static_string/detail/static_string.hpp>
+
+namespace boost
+{
+namespace static_string
+{
+
+static_assert(std::is_base_of<
+  detail::static_string_base_zero<0, char, std::char_traits<char>>,
+              static_string<0>>::value,
+              "the zero size optimization shall be used for N = 0");
+
+#ifdef BOOST_STATIC_STRING_USE_NULL_OPTIMIZATION
+static_assert(std::is_base_of<
+  detail::static_string_base_null<1, char, std::char_traits<char>>,
+              static_string<1>>::value,
+              "the null terminator optimization shall be used for N <= (std::numeric_limits<char>::max)()");
+
+static_assert(std::is_base_of<
+  detail::static_string_base_null<(std::numeric_limits<char>::max)(), char, std::char_traits<char>>,
+              static_string<(std::numeric_limits<char>::max)()>>::value,
+              "the null terminator optimization shall be used for N <= std::numeric_limits<char>::max()");
+
+static_assert(std::is_base_of<
+  detail::static_string_base_zero<(std::numeric_limits<char>::max)() + 1, char, std::char_traits<char>>,
+              static_string<(std::numeric_limits<char>::max)() + 1>>::value,
+              "the minimum size type optimization shall be used for N > std::numeric_limits<char>::max()");
+#else
+static_assert(std::is_base_of<
+  detail::static_string_base_zero<(std::numeric_limits<char>::max)() + 1, char, std::char_traits<char>>,
+              static_string<(std::numeric_limits<char>::max)() + 1>>::value,
+              "the minimum size type optimization shall be used for N > 0");
+#endif
+
+static_assert(!detail::is_input_iterator<int>::value, "is_input_iterator is incorrect");
+static_assert(!detail::is_input_iterator<double>::value, "is_input_iterator is incorrect");
+static_assert(detail::is_input_iterator<int*>::value, "is_input_iterator is incorrect");
+static_assert(detail::is_input_iterator<std::istreambuf_iterator<char>>::value, "is_input_iterator is incorrect");
+
+static_assert(!detail::is_forward_iterator<int>::value, "is_forward_iterator is incorrect");
+static_assert(!detail::is_forward_iterator<double>::value, "is_forward_iterator is incorrect");
+static_assert(detail::is_forward_iterator<int*>::value, "is_forward_iterator is incorrect");
+static_assert(!detail::is_forward_iterator<std::istreambuf_iterator<char>>::value, "is_forward_iterator is incorrect");
+}
+}