Add As/ToUnit conversions to UnitSystem

UnitsNet.Tests/BaseUnitsTests.cs

@@ -136,5 +136,45 @@ public void ToStringGivesExpectedResult()
 
             Assert.Equal("[Length]: m, [Mass]: kg, [Time]: s, [Current]: A, [Temperature]: K, [Amount]: mol, [LuminousIntensity]: cd", siBaseUnits.ToString());
         }
+
+        [Fact]
+        public void IsFullyDefined_TrueIfAllBaseUnitDefined()
+        {
+            Assert.True(new BaseUnits(LengthUnit.Meter, MassUnit.Kilogram, DurationUnit.Second,
+                ElectricCurrentUnit.Ampere, TemperatureUnit.Kelvin, AmountOfSubstanceUnit.Mole,
+                LuminousIntensityUnit.Candela).IsFullyDefined);
+        }
+
+        [Fact]
+        public void IsFullyDefined_FalseIfAnyBaseUnitIsUndefined()
+        {
+            Assert.False(new BaseUnits(mass: MassUnit.Kilogram, time: DurationUnit.Second,
+                current: ElectricCurrentUnit.Ampere, temperature: TemperatureUnit.Kelvin, amount: AmountOfSubstanceUnit.Mole,
+                luminousIntensity: LuminousIntensityUnit.Candela).IsFullyDefined);
+
+            Assert.False(new BaseUnits(length: LengthUnit.Meter, time: DurationUnit.Second,
+                current: ElectricCurrentUnit.Ampere, temperature: TemperatureUnit.Kelvin, amount: AmountOfSubstanceUnit.Mole,
+                luminousIntensity: LuminousIntensityUnit.Candela).IsFullyDefined);
+
+            Assert.False(new BaseUnits(length: LengthUnit.Meter, mass: MassUnit.Kilogram,
+                current: ElectricCurrentUnit.Ampere, temperature: TemperatureUnit.Kelvin, amount: AmountOfSubstanceUnit.Mole,
+                luminousIntensity: LuminousIntensityUnit.Candela).IsFullyDefined);
+
+            Assert.False(new BaseUnits(length: LengthUnit.Meter, mass: MassUnit.Kilogram, time: DurationUnit.Second,
+                temperature: TemperatureUnit.Kelvin, amount: AmountOfSubstanceUnit.Mole,
+                luminousIntensity: LuminousIntensityUnit.Candela).IsFullyDefined);
+
+            Assert.False(new BaseUnits(length: LengthUnit.Meter, mass: MassUnit.Kilogram, time: DurationUnit.Second,
+                current: ElectricCurrentUnit.Ampere, amount: AmountOfSubstanceUnit.Mole,
+                luminousIntensity: LuminousIntensityUnit.Candela).IsFullyDefined);
+
+            Assert.False(new BaseUnits(length: LengthUnit.Meter, mass: MassUnit.Kilogram, time: DurationUnit.Second,
+                current: ElectricCurrentUnit.Ampere, temperature: TemperatureUnit.Kelvin,
+                luminousIntensity: LuminousIntensityUnit.Candela).IsFullyDefined);
+
+            Assert.False(new BaseUnits(length: LengthUnit.Meter, mass: MassUnit.Kilogram, time: DurationUnit.Second,
+                current: ElectricCurrentUnit.Ampere, temperature: TemperatureUnit.Kelvin, amount: AmountOfSubstanceUnit.Mole
+                ).IsFullyDefined);
+        }
     }
 }

UnitsNet.Tests/CustomCode/AreaTests.cs

@@ -90,5 +90,19 @@ public void Constructor_UnitSystemSI_AssignsSIUnit()
             var area = new Area(1.0, UnitSystem.SI);
             Assert.Equal(AreaUnit.SquareMeter, area.Unit);
         }
+
+        [Fact]
+        public void As_ImperialGivenSIUnitSystem_ReturnsSIValue()
+        {
+            var imperialArea = new Area(2.0, AreaUnit.SquareInch);
+            Assert.Equal(0.00129032, imperialArea.As(UnitSystem.SI));
+        }
+
+        [Fact]
+        public void ToUnit_ImperialGivenSIUnitSystem_ReturnsSIValue()
+        {
+            var imperialArea = new Area(2.0, AreaUnit.SquareInch);
+            Assert.Equal(Area.FromSquareMeters(0.00129032), imperialArea.ToUnit(UnitSystem.SI));
+        }
     }
 }

UnitsNet.Tests/CustomCode/EnergyTests.cs

@@ -60,5 +60,19 @@ public void Constructor_UnitSystemSI_AssignsSIUnit()
             var energy = new Energy(1.0, UnitSystem.SI);
             Assert.Equal(EnergyUnit.Joule, energy.Unit);
         }
+
+        [Fact]
+        public void As_ImperialQuantityGivenSIUnitSystem_ReturnsSIValue()
+        {
+            var imperialEnergy = new Energy(2.0, EnergyUnit.BritishThermalUnit);
+            Assert.Equal(2110.11170524, imperialEnergy.As(UnitSystem.SI));
+        }
+
+        [Fact]
+        public void ToUnit_ImperialQuantityGivenSIUnitSystem_ReturnsSIValue()
+        {
+            var imperialEnergy = new Energy(2.0, EnergyUnit.BritishThermalUnit);
+            Assert.Equal(Energy.FromJoules(2110.11170524), imperialEnergy.ToUnit(UnitSystem.SI));
+        }
     }
 }

UnitsNet.Tests/CustomCode/LengthTests.cs

@@ -165,5 +165,19 @@ public void Constructor_UnitSystemSI_AssignsSIUnit()
             var length = new Length(1.0, UnitSystem.SI);
             Assert.Equal(LengthUnit.Meter, length.Unit);
         }
+
+        [Fact]
+        public void As_ImperialQuantityGivenSIUnitSystem_ReturnsSIValue()
+        {
+            var imperialLength = new Length(2.0, LengthUnit.Inch);
+            Assert.Equal(0.0508, imperialLength.As(UnitSystem.SI));
+        }
+
+        [Fact]
+        public void ToUnit_ImperialQuantityGivenSIUnitSystem_ReturnsSIValue()
+        {
+            var imperialLength = new Length(2.0, LengthUnit.Inch);
+            Assert.Equal(Length.FromMeters(0.0508), imperialLength.ToUnit(UnitSystem.SI));
+        }
     }
 }

UnitsNet.Tests/IQuantityTests.cs

@@ -16,11 +16,39 @@ public void As_GivenWrongUnitType_ThrowsArgumentException()
             Assert.Throws<ArgumentException>(() => length.As(MassUnit.Kilogram));
         }
 
+        [Fact]
+        public void As_GivenNullUnitSystem_ThrowsArgumentNullException()
+        {
+            IQuantity imperialLengthQuantity = new Length(2.0, LengthUnit.Inch);
+            Assert.Throws<ArgumentNullException>(() => imperialLengthQuantity.As((UnitSystem)null));
+        }
+
+        [Fact]
+        public void As_ImperialQuantityGivenSIUnitSystem_ReturnsSIValue()
+        {
+            IQuantity imperialLengthQuantity = new Length(2.0, LengthUnit.Inch);
+            Assert.Equal(0.0508, imperialLengthQuantity.As(UnitSystem.SI));
+        }
+
         [Fact]
         public void ToUnit_GivenWrongUnitType_ThrowsArgumentException()
         {
             IQuantity length = Length.FromMeters(1.2345);
             Assert.Throws<ArgumentException>(() => length.ToUnit(MassUnit.Kilogram));
         }
+
+        [Fact]
+        public void ToUnit_GivenNullUnitSystem_ThrowsArgumentNullException()
+        {
+            IQuantity imperialLengthQuantity = new Length(2.0, LengthUnit.Inch);
+            Assert.Throws<ArgumentNullException>(() => imperialLengthQuantity.ToUnit((UnitSystem)null));
+        }
+
+        [Fact]
+        public void ToUnit_ImperialQuantityGivenSIUnitSystem_ReturnsSIValue()
+        {
+            IQuantity imperialLengthQuantity = new Length(2.0, LengthUnit.Inch);
+            Assert.Equal(Length.FromMeters(0.0508), imperialLengthQuantity.ToUnit(UnitSystem.SI));
+        }
     }
 }

UnitsNet/BaseUnits.cs

@@ -46,6 +46,14 @@ public BaseUnits(
             Temperature = temperature;
             Amount = amount;
             LuminousIntensity = luminousIntensity;
+
+            IsFullyDefined = Length != LengthUnit.Undefined &&
+                Mass != MassUnit.Undefined &&
+                Time != DurationUnit.Undefined &&
+                Current != ElectricCurrentUnit.Undefined &&
+                Temperature != TemperatureUnit.Undefined &&
+                Amount != AmountOfSubstanceUnit.Undefined &&
+                LuminousIntensity != LuminousIntensityUnit.Undefined;
         }
 
         /// <inheritdoc />
@@ -181,5 +189,10 @@ public override string ToString()
         /// Gets the luminous intensity unit (J).
         /// </summary>
         public LuminousIntensityUnit LuminousIntensity{ get; }
+
+        /// <summary>
+        /// Gets whether or not all of the base units are defined.
+        /// </summary>
+        public bool IsFullyDefined { get; }
     }
 }