From 037503cbc6dee7cad718ee1c268054acd1d16f3e Mon Sep 17 00:00:00 2001
From: Mateusz Pusz <mateusz.pusz@gmail.com>
Date: Mon, 10 Feb 2020 20:35:32 +0100
Subject: [PATCH] deduced_unit fixed + unit test for mass unit added

---
 src/include/units/bits/deduced_unit.h      |  3 ++-
 src/include/units/physical/si/mass.h       |  4 ++--
 test/unit_test/static/custom_unit_test.cpp | 12 ++++++++++++
 3 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/src/include/units/bits/deduced_unit.h b/src/include/units/bits/deduced_unit.h
index 82a28fc6..e8832da6 100644
--- a/src/include/units/bits/deduced_unit.h
+++ b/src/include/units/bits/deduced_unit.h
@@ -61,7 +61,8 @@ struct derived_ratio<exp_list<>, Us...> {
 template<typename E, typename... ERest, Unit U, Unit... URest>
 struct derived_ratio<exp_list<E, ERest...>, U, URest...> {
   using rest_ratio = derived_ratio<exp_list<ERest...>, URest...>::ratio;
-  using ratio = ratio_op<rest_ratio, E::num, E::den, typename U::ratio>::ratio;
+  using unit_ratio = ratio_op<rest_ratio, E::num, E::den, typename U::ratio>::ratio;
+  using ratio = ratio_divide<unit_ratio, typename dimension_unit<typename E::dimension>::ratio>;
 };
 
 template<DerivedDimension D, Unit... Us>
diff --git a/src/include/units/physical/si/mass.h b/src/include/units/physical/si/mass.h
index 37646b1a..1a4dd5f0 100644
--- a/src/include/units/physical/si/mass.h
+++ b/src/include/units/physical/si/mass.h
@@ -28,8 +28,8 @@
 
 namespace units::si {
 
-struct kilogram : named_unit<kilogram, "kg", no_prefix> {};
-struct gram : named_scaled_unit<gram, "g", prefix, ratio<1, 1'000>, kilogram> {};
+struct gram : named_unit<gram, "g", prefix> {};
+struct kilogram : prefixed_unit<kilogram, kilo, gram> {};
 struct tonne : named_scaled_unit<tonne, "t", prefix, ratio<1'000>, kilogram> {};
 
 struct dalton : named_scaled_unit<dalton, "Da", no_prefix, ratio<16'605'390'666'050, 10'000'000'000'000, -27>, kilogram> {};
diff --git a/test/unit_test/static/custom_unit_test.cpp b/test/unit_test/static/custom_unit_test.cpp
index 54c0c056..3c0ff742 100644
--- a/test/unit_test/static/custom_unit_test.cpp
+++ b/test/unit_test/static/custom_unit_test.cpp
@@ -20,7 +20,9 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 // SOFTWARE.
 
+#include <units/physical/si/mass.h>
 #include <units/physical/si/voltage.h>
+#include <units/physical/si/time.h>
 #include <units/physical/si/frequency.h>
 #include <units/math.h>
 
@@ -54,3 +56,13 @@ static_assert(std::is_same_v<decltype(pow<2>(amplitude_spectral_density<volt_per
 static_assert(std::is_same_v<decltype(sqrt(power_spectral_density<sq_volt_per_hertz>(16))), decltype(amplitude_spectral_density<volt_per_sqrt_hertz>(4))>);
 
 }
+
+namespace {
+
+struct kilogram_per_second : unit<kilogram_per_second> {};
+struct dim_mass_rate : derived_dimension<dim_mass_rate, kilogram_per_second, units::exp<si::dim_mass, 1>, units::exp<si::dim_time, -1>> {};
+struct kilogram_per_hour : deduced_unit<kilogram_per_hour, dim_mass_rate, si::kilogram, si::hour> {};
+constexpr auto a = 1kg / 1h;
+static_assert(std::is_same_v<decltype(a)::unit, kilogram_per_hour>);
+
+}