fix bugs in temperature conversion

src/main/java/io/github/ititus/si/dimension/BaseDimension.java

@@ -1,6 +1,7 @@
 package io.github.ititus.si.dimension;
 
 import io.github.ititus.data.Lazy;
+import io.github.ititus.internal.Config;
 
 import java.util.Collections;
 import java.util.EnumMap;
@@ -12,7 +13,7 @@ public enum BaseDimension implements Dimension {
     MASS('M'),
     TIME('T'),
     ELECTRIC_CURRENT('I'),
-    THERMODYNAMIC_TEMPERATURE('\u0398'),
+    TEMPERATURE(Config.FORCE_ASCII ? 'O' : '\u0398'),
     SUBSTANCE_AMOUNT('N'),
     LUMINOUS_INTENSITY('J');
 

src/main/java/io/github/ititus/si/quantity/type/Temperature.java

@@ -0,0 +1,14 @@
+package io.github.ititus.si.quantity.type;
+
+import io.github.ititus.si.dimension.BaseDimension;
+
+import static io.github.ititus.si.unit.Units.KELVIN;
+
+public final class Temperature extends AbstractQuantityType<Temperature> {
+
+    public static final Temperature TEMPERATURE = new Temperature();
+
+    private Temperature() {
+        super(BaseDimension.TEMPERATURE, () -> KELVIN);
+    }
+}

src/main/java/io/github/ititus/si/unit/Units.java

@@ -42,7 +42,7 @@
 import static io.github.ititus.si.quantity.type.SolidAngle.SOLID_ANGLE;
 import static io.github.ititus.si.quantity.type.Speed.SPEED;
 import static io.github.ititus.si.quantity.type.SubstanceAmount.SUBSTANCE_AMOUNT;
-import static io.github.ititus.si.quantity.type.ThermodynamicTemperature.THERMODYNAMIC_TEMPERATURE;
+import static io.github.ititus.si.quantity.type.Temperature.TEMPERATURE;
 import static io.github.ititus.si.quantity.type.Time.TIME;
 import static io.github.ititus.si.quantity.type.Volume.VOLUME;
 
@@ -59,7 +59,7 @@ public final class Units {
     public static final Unit<Mass> GRAM = new BaseUnit<>(MASS, "g");
     public static final Unit<Time> SECOND = new BaseUnit<>(TIME, "s");
     public static final Unit<ElectricCurrent> AMPERE = new BaseUnit<>(ELECTRIC_CURRENT, "A");
-    public static final Unit<ThermodynamicTemperature> KELVIN = new BaseUnit<>(THERMODYNAMIC_TEMPERATURE, "K");
+    public static final Unit<Temperature> KELVIN = new BaseUnit<>(TEMPERATURE, "K");
     public static final Unit<SubstanceAmount> MOLE = new BaseUnit<>(SUBSTANCE_AMOUNT, "mol");
     public static final Unit<LuminousIntensity> CANDELA = new BaseUnit<>(LUMINOUS_INTENSITY, "cd");
 
@@ -103,9 +103,9 @@ public final class Units {
     // Electric Current
 
     // Thermodynamic Temperature
-    public static final Unit<ThermodynamicTemperature> CELSIUS = KELVIN.shift(ofExp(-23715, -2)).alternate("°C");
-    public static final Unit<ThermodynamicTemperature> RANKINE = KELVIN.multiply(of(9, 5)).alternate("°R");
-    public static final Unit<ThermodynamicTemperature> FAHRENHEIT = RANKINE.shift(ofExp(-45967, -2)).alternate("°F");
+    public static final Unit<Temperature> CELSIUS = KELVIN.shift(ofExp(27315, -2)).alternate("°C");
+    public static final Unit<Temperature> RANKINE = KELVIN.multiply(of(5, 9)).alternate("°R");
+    public static final Unit<Temperature> FAHRENHEIT = RANKINE.shift(ofExp(45967, -2)).alternate("°F");
 
     // Amount of Substance
 

src/main/java/io/github/ititus/si/unit/converter/LinearConverter.java

@@ -59,7 +59,7 @@ public UnitConverter concat(UnitConverter converter) {
             return this;
         } else if (converter instanceof LinearConverter) {
             LinearConverter that = (LinearConverter) converter;
-            return of(factor.multiply(that.factor), that.factor.multiply(shift).add(this.shift));
+            return of(factor.multiply(that.factor), that.factor.multiply(shift).add(that.shift));
         }
 
         return UnitConverter.compound(List.of(this, converter));

src/test/java/io/github/ititus/si/quantity/type/TemperatureTest.java

@@ -5,25 +5,56 @@
 
 import static io.github.ititus.assertions.Assertions.assertThat;
 import static io.github.ititus.si.quantity.value.QuantityValue.of;
-import static io.github.ititus.si.unit.Units.CELSIUS;
-import static io.github.ititus.si.unit.Units.KELVIN;
+import static io.github.ititus.si.unit.Units.*;
 import static org.assertj.core.data.Percentage.withPercentage;
 
 class TemperatureTest {
 
     @Test
-    void kelvinToCelsius() {
-        Quantity<ThermodynamicTemperature> kelvin = KELVIN.get(0);
-        Quantity<ThermodynamicTemperature> celsius = kelvin.convertTo(CELSIUS);
+    void fromKelvin() {
+        Quantity<Temperature> kelvin = KELVIN.get(42);
+        Quantity<Temperature> celsius = kelvin.convertTo(CELSIUS);
+        Quantity<Temperature> rankine = kelvin.convertTo(RANKINE);
+        Quantity<Temperature> fahrenheit = kelvin.convertTo(FAHRENHEIT);
 
-        assertThat(celsius.getValue()).isCloseTo(of(-273.15), withPercentage(1.0));
+        assertThat(celsius.getValue()).isCloseTo(of(-231.15), withPercentage(1.0));
+        assertThat(rankine.getValue()).isCloseTo(of(75.6), withPercentage(1.0));
+        assertThat(fahrenheit.getValue()).isCloseTo(of(-384.07), withPercentage(1.0));
     }
 
     @Test
-    void celsiusToKelvin() {
-        Quantity<ThermodynamicTemperature> celsius = CELSIUS.get(0);
-        Quantity<ThermodynamicTemperature> kelvin = celsius.convertTo(KELVIN);
+    void fromCelsius() {
+        Quantity<Temperature> celsius = CELSIUS.get(42);
+        Quantity<Temperature> kelvin = celsius.convertTo(KELVIN);
+        Quantity<Temperature> rankine = celsius.convertTo(RANKINE);
+        Quantity<Temperature> fahrenheit = celsius.convertTo(FAHRENHEIT);
 
-        assertThat(kelvin.getValue()).isCloseTo(of(273.15), withPercentage(1.0));
+        assertThat(kelvin.getValue()).isCloseTo(of(315.15), withPercentage(1.0));
+        assertThat(rankine.getValue()).isCloseTo(of(567.27), withPercentage(1.0));
+        assertThat(fahrenheit.getValue()).isCloseTo(of(107.6), withPercentage(1.0));
+    }
+
+    @Test
+    void fromRankine() {
+        Quantity<Temperature> rankine = RANKINE.get(42);
+        Quantity<Temperature> kelvin = rankine.convertTo(KELVIN);
+        Quantity<Temperature> celsius = rankine.convertTo(CELSIUS);
+        Quantity<Temperature> fahrenheit = rankine.convertTo(FAHRENHEIT);
+
+        assertThat(kelvin.getValue()).isCloseTo(of(23.33), withPercentage(1.0));
+        assertThat(celsius.getValue()).isCloseTo(of(-249.82), withPercentage(1.0));
+        assertThat(fahrenheit.getValue()).isCloseTo(of(-417.67), withPercentage(1.0));
+    }
+
+    @Test
+    void fromFahrenheit() {
+        Quantity<Temperature> fahrenheit = FAHRENHEIT.get(42);
+        Quantity<Temperature> kelvin = fahrenheit.convertTo(KELVIN);
+        Quantity<Temperature> celsius = fahrenheit.convertTo(CELSIUS);
+        Quantity<Temperature> rankine = fahrenheit.convertTo(RANKINE);
+
+        assertThat(kelvin.getValue()).isCloseTo(of(278.71), withPercentage(1.0));
+        assertThat(celsius.getValue()).isCloseTo(of(5.56), withPercentage(1.0));
+        assertThat(rankine.getValue()).isCloseTo(of(501.67), withPercentage(1.0));
     }
 }

src/test/java/io/github/ititus/si/quantity/type/TimeTest.java

@@ -0,0 +1,31 @@
+package io.github.ititus.si.quantity.type;
+
+import io.github.ititus.si.quantity.Quantity;
+import org.junit.jupiter.api.Test;
+
+import static io.github.ititus.assertions.Assertions.assertThat;
+import static io.github.ititus.math.number.BigRational.ofExp;
+import static io.github.ititus.si.prefix.MetricPrefix.NANO;
+import static io.github.ititus.si.quantity.value.QuantityValue.of;
+import static io.github.ititus.si.unit.Units.*;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.data.Percentage.withPercentage;
+
+class TimeTest {
+
+    @Test
+    void secondsToMinutes() {
+        Quantity<Time> seconds = SECOND.get(42);
+        Quantity<Time> minutes = seconds.convertTo(MINUTE);
+
+        assertThat(minutes.getValue()).isCloseTo(of(0.7), withPercentage(1));
+    }
+
+    @Test
+    void minutesToSeconds() {
+        Quantity<Time> minutes = MINUTE.get(42);
+        Quantity<Time> seconds = minutes.convertTo(SECOND);
+
+        assertThat(seconds.getValue()).isCloseTo(of(2520), withPercentage(1));
+    }
+}