diff --git a/test/iso_week/weeknum.pass.cpp b/test/iso_week/weeknum.pass.cpp
new file mode 100644
index 0000000..1289d32
--- /dev/null
+++ b/test/iso_week/weeknum.pass.cpp
@@ -0,0 +1,121 @@
+// The MIT License (MIT)
+// 
+// Copyright (c) 2015 Howard Hinnant
+// 
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+// 
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+// class weeknum
+// {
+//     unsigned char wn_;
+// 
+// public:
+//     explicit constexpr weeknum(unsigned wn) noexcept;
+// 
+//     weeknum& operator++()    noexcept;
+//     weeknum  operator++(int) noexcept;
+//     weeknum& operator--()    noexcept;
+//     weeknum  operator--(int) noexcept;
+// 
+//     weeknum& operator+=(const weeks& y) noexcept;
+//     weeknum& operator-=(const weeks& y) noexcept;
+// 
+//     constexpr explicit operator unsigned() const noexcept;
+//     constexpr bool ok() const noexcept;
+// };
+// 
+// constexpr bool operator==(const weeknum& x, const weeknum& y) noexcept;
+// constexpr bool operator!=(const weeknum& x, const weeknum& y) noexcept;
+// constexpr bool operator< (const weeknum& x, const weeknum& y) noexcept;
+// constexpr bool operator> (const weeknum& x, const weeknum& y) noexcept;
+// constexpr bool operator<=(const weeknum& x, const weeknum& y) noexcept;
+// constexpr bool operator>=(const weeknum& x, const weeknum& y) noexcept;
+// 
+// constexpr weeknum  operator+(const weeknum& x, const weeks&   y) noexcept;
+// constexpr weeknum  operator+(const weeks&   x, const weeknum& y) noexcept;
+// constexpr weeknum  operator-(const weeknum& x, const weeks&   y) noexcept;
+// constexpr weeks    operator-(const weeknum& x, const weeknum& y) noexcept;
+// 
+// std::ostream& operator<<(std::ostream& os, const weeknum& wn);
+//
+// constexpr weeknum operator "" _w(unsigned long long wn) noexcept;
+
+#include "iso_week.h"
+
+#include <cassert>
+#include <sstream>
+#include <type_traits>
+
+static_assert( std::is_trivially_destructible<iso_week::weeknum>{}, "");
+static_assert(!std::is_default_constructible<iso_week::weeknum>{}, "");
+static_assert( std::is_trivially_copy_constructible<iso_week::weeknum>{}, "");
+static_assert( std::is_trivially_copy_assignable<iso_week::weeknum>{}, "");
+static_assert( std::is_trivially_move_constructible<iso_week::weeknum>{}, "");
+static_assert( std::is_trivially_move_assignable<iso_week::weeknum>{}, "");
+
+static_assert(std::is_trivially_copyable<iso_week::weeknum>{}, "");
+static_assert(std::is_standard_layout<iso_week::weeknum>{}, "");
+static_assert(std::is_literal_type<iso_week::weeknum>{}, "");
+
+static_assert( std::is_nothrow_constructible<iso_week::weeknum, unsigned>{}, "");
+static_assert(!std::is_convertible<unsigned, iso_week::weeknum>{}, "");
+static_assert( std::is_nothrow_constructible<unsigned, iso_week::weeknum>{}, "");
+static_assert(!std::is_convertible<iso_week::weeknum, unsigned>{}, "");
+static_assert(static_cast<unsigned>(iso_week::weeknum{3}) == 3, "");
+
+int
+main()
+{
+    using namespace iso_week;
+    using namespace std::chrono;
+
+    static_assert(weeknum{2} == 2_w, "");
+    static_assert(unsigned{weeknum{2}} == 2, "");
+    static_assert(unsigned{weeknum{3}} == 3, "");
+    static_assert(weeknum{2} != 3_w, "");
+    static_assert(weeknum{2} < 3_w, "");
+    static_assert(weeknum{3} > 2_w, "");
+    static_assert(weeknum{2} <= 2_w, "");
+    static_assert(weeknum{3} >= 2_w, "");
+
+    auto wn = weeknum{4};
+    assert(++wn == weeknum{5});
+    assert(wn == weeknum{5});
+    assert(wn++ == weeknum{5});
+    assert(wn == weeknum{6});
+    assert(--wn == weeknum{5});
+    assert(wn == weeknum{5});
+    assert(wn-- == weeknum{5});
+    assert(wn == weeknum{4});
+
+    static_assert(!weeknum{0}.ok(), "");
+    static_assert( weeknum{1}.ok(), "");
+    static_assert( weeknum{53}.ok(), "");
+    static_assert(!weeknum{54}.ok(), "");
+
+    static_assert(15_w - 10_w == weeks{5}, "");
+    static_assert(15_w - weeks{5} == 10_w, "");
+    static_assert(15_w == weeks{5} + 10_w, "");
+    static_assert(15_w == 10_w + weeks{5}, "");
+    static_assert(10_w - 15_w == -weeks{5}, "");
+
+    auto w = 5_w;
+    std::ostringstream os;
+    os << w;
+    assert(os.str() == "W05");
+}
diff --git a/test/iso_week/weeknum_p_weeknum.fail.cpp b/test/iso_week/weeknum_p_weeknum.fail.cpp
new file mode 100644
index 0000000..8d2b0db
--- /dev/null
+++ b/test/iso_week/weeknum_p_weeknum.fail.cpp
@@ -0,0 +1,32 @@
+// The MIT License (MIT)
+// 
+// Copyright (c) 2015 Howard Hinnant
+// 
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+// 
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+// weeknum + weeknum not allowed
+
+#include "iso_week.h"
+
+int
+main()
+{
+    using namespace iso_week;
+    auto x = 3_w + 4_w;
+}