From f69b217beaad9a1a56bc19f0304b026172fcde1e Mon Sep 17 00:00:00 2001
From: Vlad Voronenkov <v.v.voronenkov@ya.ru>
Date: Fri, 5 Aug 2022 21:34:54 +0200
Subject: [PATCH] Add ElectricCurrentDensity quantity with related units.

---
 src/si/electric_current_density.rs | 54 ++++++++++++++++++++++++++++++
 src/si/mod.rs                      |  1 +
 2 files changed, 55 insertions(+)
 create mode 100644 src/si/electric_current_density.rs

diff --git a/src/si/electric_current_density.rs b/src/si/electric_current_density.rs
new file mode 100644
index 00000000..c4ef062a
--- /dev/null
+++ b/src/si/electric_current_density.rs
@@ -0,0 +1,54 @@
+//! Electric current density (base unit ampere per square meter, m⁻² · A).
+
+quantity! {
+    /// Electric current density (base unit ampere per square meter, m⁻² · A).
+    quantity: ElectricCurrentDensity; "electric current density";
+    /// Dimension of electric current density, L⁻²I (base unit ampere per square meter, A · m⁻²).
+    dimension: ISQ<
+        N2,     // length
+        Z0,     // mass
+        Z0,     // time
+        P1,     // electric current
+        Z0,     // thermodynamic temperature
+        Z0,     // amount of substance
+        Z0>;    // luminous intensity
+        kind: dyn (crate::si::marker::ConstituentConcentrationKind);
+    units {
+        @ampere_per_square_meter: prefix!(none); "A/m²", "ampere per square meter",
+            "amperes per square meter";
+        @ampere_per_square_centimeter: prefix!(none) / prefix!(centi) / prefix!(centi); "A/cm²",
+            "ampere per square centimeter", "amperes per square centimeter";
+        @ampere_per_square_millimeter: prefix!(none) / prefix!(milli) / prefix!(milli); "A/mm²",
+            "ampere per square millimeter", "amperes per square millimeter";
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    storage_types! {
+        use crate::num::One;
+        use crate::si::area as a;
+        use crate::si::electric_current as i;
+        use crate::si::electric_current_density as ecd;
+        use crate::si::quantities::*;
+        use crate::tests::Test;
+
+        #[test]
+        fn check_dimension() {
+            let _: ElectricCurrentDensity<V> = (ElectricCurrent::new::<i::ampere>(V::one())
+                / Area::new::<a::square_meter>(V::one())).into();
+        }
+
+        #[test]
+        fn check_units() {
+            test::<ecd::ampere_per_square_meter, i::ampere, a::square_meter>();
+            test::<ecd::ampere_per_square_centimeter, i::ampere, a::square_centimeter>();
+            test::<ecd::ampere_per_square_millimeter, i::ampere, a::square_millimeter>();
+
+            fn test<ECD: ecd::Conversion<V>, I: i::Conversion<V>, A: a::Conversion<V>>() {
+                Test::assert_approx_eq(&ElectricCurrentDensity::new::<ECD>(V::one()),
+                    &(ElectricCurrent::new::<I>(V::one()) / Area::new::<A>(V::one())).into());
+            }
+        }
+    }
+}
diff --git a/src/si/mod.rs b/src/si/mod.rs
index 18b09fbb..0254eb7b 100644
--- a/src/si/mod.rs
+++ b/src/si/mod.rs
@@ -69,6 +69,7 @@ system! {
         electric_charge_linear_density::ElectricChargeLinearDensity,
         electric_charge_volumetric_density::ElectricChargeVolumetricDensity,
         electric_current::ElectricCurrent,
+        electric_current_density::ElectricCurrentDensity,
         electric_dipole_moment::ElectricDipoleMoment,
         electric_displacement_field::ElectricDisplacementField,
         electric_field::ElectricField,