Fix group calculations to use GroupItem's system unit (#4563)

* QuantityType improve group calculations
* support inverse units, extend tests
* refactoring
* javadoc and code simplification
* use streams; make sums absolute

Signed-off-by: Andrew Fiddian-Green <software@whitebear.ch>

bundles/org.openhab.core/src/main/java/org/openhab/core/internal/items/GroupFunctionHelper.java

@@ -15,7 +15,7 @@ package org.openhab.core.internal.items;
 import java.util.ArrayList;
 import java.util.List;
 
-import javax.measure.Quantity;
+import javax.measure.Unit;
 
 import org.eclipse.jdt.annotation.NonNullByDefault;
 import org.eclipse.jdt.annotation.Nullable;
@@ -48,13 +48,12 @@ public class GroupFunctionHelper {
      * arithmetic group function will take unit conversion into account.
      *
      * @param function the {@link GroupFunctionDTO} describing the group function.
-     * @param baseItem an optional {@link Item} defining the dimension for unit conversion.
+     * @param baseItem an optional {@link Item} defining the dimension/unit for unit conversion.
      * @return a {@link GroupFunction} according to the given parameters.
      */
     public GroupFunction createGroupFunction(GroupFunctionDTO function, @Nullable Item baseItem) {
-        Class<? extends Quantity<?>> dimension = getDimension(baseItem);
-        if (dimension != null) {
-            return createDimensionGroupFunction(function, baseItem, dimension);
+        if (baseItem instanceof NumberItem baseNumberItem && baseNumberItem.getDimension() != null) {
+            return createDimensionGroupFunction(function, baseNumberItem);
         }
         return createDefaultGroupFunction(function, baseItem);
     }
@@ -78,30 +77,25 @@ public class GroupFunctionHelper {
         return states;
     }
 
-    private @Nullable Class<? extends Quantity<?>> getDimension(@Nullable Item baseItem) {
-        if (baseItem instanceof NumberItem numberItem) {
-            return numberItem.getDimension();
-        }
-        return null;
-    }
-
-    private GroupFunction createDimensionGroupFunction(GroupFunctionDTO function, @Nullable Item baseItem,
-            Class<? extends Quantity<?>> dimension) {
+    private GroupFunction createDimensionGroupFunction(GroupFunctionDTO function, NumberItem baseItem) {
         final String functionName = function.name;
-        switch (functionName.toUpperCase()) {
-            case "AVG":
-                return new QuantityTypeArithmeticGroupFunction.Avg(dimension);
-            case "MEDIAN":
-                return new QuantityTypeArithmeticGroupFunction.Median(dimension, baseItem);
-            case "SUM":
-                return new QuantityTypeArithmeticGroupFunction.Sum(dimension);
-            case "MIN":
-                return new QuantityTypeArithmeticGroupFunction.Min(dimension);
-            case "MAX":
-                return new QuantityTypeArithmeticGroupFunction.Max(dimension);
-            default:
-                return createDefaultGroupFunction(function, baseItem);
+        Unit<?> baseItemUnit = baseItem.getUnit();
+        if (baseItemUnit != null) {
+            switch (functionName.toUpperCase()) {
+                case "AVG":
+                    return new QuantityTypeArithmeticGroupFunction.Avg(baseItemUnit);
+                case "MEDIAN":
+                    return new QuantityTypeArithmeticGroupFunction.Median(baseItemUnit);
+                case "SUM":
+                    return new QuantityTypeArithmeticGroupFunction.Sum(baseItemUnit);
+                case "MIN":
+                    return new QuantityTypeArithmeticGroupFunction.Min(baseItemUnit);
+                case "MAX":
+                    return new QuantityTypeArithmeticGroupFunction.Max(baseItemUnit);
+                default:
+            }
         }
+        return createDefaultGroupFunction(function, baseItem);
     }
 
     private GroupFunction createDefaultGroupFunction(GroupFunctionDTO function, @Nullable Item baseItem) {

bundles/org.openhab.core/src/main/java/org/openhab/core/library/types/QuantityTypeArithmeticGroupFunction.java

@@ -13,12 +13,11 @@
 package org.openhab.core.library.types;
 
 import java.math.BigDecimal;
-import java.math.MathContext;
-import java.util.ArrayList;
 import java.util.List;
+import java.util.Objects;
+import java.util.Optional;
 import java.util.Set;
 
-import javax.measure.Quantity;
 import javax.measure.Unit;
 
 import org.eclipse.jdt.annotation.NonNullByDefault;
@@ -26,31 +25,38 @@ import org.eclipse.jdt.annotation.Nullable;
 import org.openhab.core.items.GroupFunction;
 import org.openhab.core.items.GroupItem;
 import org.openhab.core.items.Item;
-import org.openhab.core.library.items.NumberItem;
 import org.openhab.core.types.State;
 import org.openhab.core.types.UnDefType;
 import org.openhab.core.util.Statistics;
 
+import tech.units.indriya.AbstractUnit;
+
 /**
  * This interface is a container for dimension based functions that require {@link QuantityType}s for its calculations.
  *
  * @author Henning Treu - Initial contribution
+ * @author Andrew Fiddian-Green - Normalise calculations based on the Unit of the GroupItem
  */
 @NonNullByDefault
 public interface QuantityTypeArithmeticGroupFunction extends GroupFunction {
 
     abstract class DimensionalGroupFunction implements GroupFunction {
 
-        protected final Class<? extends Quantity<?>> dimension;
+        protected final Unit<?> baseItemUnit; // the actual unit of the owning group item
+        protected final Unit<?> systemUnit; // the reference unit for group member calculations
 
-        public DimensionalGroupFunction(Class<? extends Quantity<?>> dimension) {
-            this.dimension = dimension;
+        public DimensionalGroupFunction(Unit<?> baseItemUnit) {
+            this.baseItemUnit = baseItemUnit;
+            this.systemUnit = baseItemUnit.getSystemUnit();
         }
 
         @Override
         public @Nullable <T extends State> T getStateAs(@Nullable Set<Item> items, Class<T> stateClass) {
             State state = calculate(items);
             if (stateClass.isInstance(state)) {
+                if (state instanceof QuantityType<?> quantity) {
+                    state = toInvertibleUnit(quantity, baseItemUnit);
+                }
                 return stateClass.cast(state);
             } else {
                 return null;
@@ -62,102 +68,76 @@ public interface QuantityTypeArithmeticGroupFunction extends GroupFunction {
             return new State[0];
         }
 
-        protected boolean isSameDimension(@Nullable Item item) {
-            if (item instanceof GroupItem groupItem) {
-                return isSameDimension(groupItem.getBaseItem());
+        /**
+         * Convert the given {@link QuantityType} to an equivalent based on the given {@link Unit}. The conversion can
+         * be made to both inverted and non-inverted units, so invertible type conversions (e.g. Mirek <=> Kelvin) are
+         * supported.
+         * <p>
+         * Note: we can use {@link QuantityType.toInvertibleUnit()} if OH Core PR #4561 is merged.
+         *
+         * @param source the {@link QuantityType} to be converted.
+         * @param targetUnit the {@link Unit} to convert to.
+         *
+         * @return a new {@link QuantityType} based on 'targetUnit' or null.
+         */
+        private @Nullable QuantityType<?> toInvertibleUnit(QuantityType<?> source, Unit<?> targetUnit) {
+            if (!targetUnit.equals(source.getUnit()) && !targetUnit.isCompatible(AbstractUnit.ONE)
+                    && source.getUnit().inverse().isCompatible(targetUnit)) {
+                QuantityType<?> sourceInSystemUnit = source.toUnit(source.getUnit().getSystemUnit());
+                return sourceInSystemUnit != null ? sourceInSystemUnit.inverse().toUnit(targetUnit) : null;
             }
-            return item instanceof NumberItem ni && dimension.equals(ni.getDimension());
+            return source.toUnit(targetUnit);
+        }
+
+        /**
+         * Convert the given item {@link State} to a {@link QuantityType} based on the {@link Unit} of the
+         * {@link GroupItem} i.e. 'referenceUnit'. Returns null if the {@link State} is not a {@link QuantityType} or
+         * if the {@link QuantityType} could not be converted to 'referenceUnit'.
+         *
+         * The conversion can be made to both inverted and non-inverted units, so invertible type conversions (e.g.
+         * Mirek <=> Kelvin) are supported.
+         *
+         * @param state the State of any given group member item
+         * @return a QuantityType or null
+         */
+        private @Nullable QuantityType<?> toQuantityTypeOfUnit(@Nullable State state, Unit<?> unit) {
+            return state instanceof QuantityType<?> quantity //
+                    ? toInvertibleUnit(quantity, unit)
+                    : null;
+        }
+
+        /**
+         * Convert a set of {@link Item} to a respective list of {@link QuantityType}. Exclude any {@link Item}s whose
+         * current {@link State} is not a {@link QuantityType}. Convert any remaining {@link QuantityType} to the
+         * 'referenceUnit' and exclude any values that did not convert.
+         *
+         * @param items a list of {@link Item}
+         * @return a list of {@link QuantityType} converted to the 'referenceUnit'
+         */
+        @SuppressWarnings({ "rawtypes" })
+        protected List<QuantityType> toQuantityTypesOfUnit(Set<Item> items, Unit<?> unit) {
+            return items.stream().map(i -> i.getState()).map(s -> toQuantityTypeOfUnit(s, unit))
+                    .filter(Objects::nonNull).map(s -> (QuantityType) s).toList();
         }
     }
 
     /**
-     * This calculates the numeric average over all item states of {@link QuantityType}.
+     * Calculates the average of a set of item states whose value could be converted to the 'referenceUnit'.
      */
     class Avg extends DimensionalGroupFunction {
 
-        public Avg(Class<? extends Quantity<?>> dimension) {
-            super(dimension);
-        }
-
-        @Override
-        @SuppressWarnings({ "unchecked", "rawtypes" })
-        public State calculate(@Nullable Set<Item> items) {
-            if (items == null || items.isEmpty()) {
-                return UnDefType.UNDEF;
-            }
-
-            QuantityType<?> sum = null;
-            int count = 0;
-            for (Item item : items) {
-                if (isSameDimension(item)) {
-                    QuantityType itemState = item.getStateAs(QuantityType.class);
-                    if (itemState != null) {
-                        if (sum == null) {
-                            sum = itemState; // initialise the sum from the first item
-                            count++;
-                        } else {
-                            itemState = itemState.toInvertibleUnit(sum.getUnit());
-                            if (itemState != null) {
-                                sum = sum.add(itemState);
-                                count++;
-                            }
-                        }
-                    }
-                }
-            }
-
-            if (sum != null && count > 0) {
-                BigDecimal result = sum.toBigDecimal().divide(BigDecimal.valueOf(count), MathContext.DECIMAL128);
-                return new QuantityType(result, sum.getUnit());
-            }
-
-            return UnDefType.UNDEF;
-        }
-    }
-
-    /**
-     * This calculates the numeric median over all item states of {@link QuantityType}.
-     */
-    class Median extends DimensionalGroupFunction {
-
-        private @Nullable Item baseItem;
-
-        public Median(Class<? extends Quantity<?>> dimension, @Nullable Item baseItem) {
-            super(dimension);
-            this.baseItem = baseItem;
+        public Avg(Unit<?> baseItemUnit) {
+            super(baseItemUnit);
         }
 
         @Override
         @SuppressWarnings({ "unchecked", "rawtypes" })
         public State calculate(@Nullable Set<Item> items) {
             if (items != null) {
-                List<BigDecimal> values = new ArrayList<>();
-                Unit<?> unit = null;
-                if (baseItem instanceof NumberItem numberItem) {
-                    unit = numberItem.getUnit();
-                }
-                for (Item item : items) {
-                    if (!isSameDimension(item)) {
-                        continue;
-                    }
-                    QuantityType itemState = item.getStateAs(QuantityType.class);
-                    if (itemState == null) {
-                        continue;
-                    }
-                    if (unit == null) {
-                        unit = itemState.getUnit(); // set it to the first item's unit
-                    }
-                    if (itemState.toInvertibleUnit(unit) instanceof QuantityType<?> inverted) {
-                        values.add(inverted.toBigDecimal());
-                    }
-                }
-
-                if (!values.isEmpty()) {
-                    BigDecimal median = Statistics.median(values);
-                    if (median != null && unit != null) {
-                        return new QuantityType<>(median, unit);
-                    }
-
+                List<QuantityType> systemUnitQuantities = toQuantityTypesOfUnit(items, systemUnit);
+                if (!systemUnitQuantities.isEmpty()) {
+                    return systemUnitQuantities.stream().reduce(new QuantityType<>(0, systemUnit), QuantityType::add)
+                            .divide(BigDecimal.valueOf(systemUnitQuantities.size()));
                 }
             }
             return UnDefType.UNDEF;
@@ -165,105 +145,99 @@ public interface QuantityTypeArithmeticGroupFunction extends GroupFunction {
     }
 
     /**
-     * This calculates the numeric sum over all item states of {@link QuantityType}.
+     * Calculates the median of a set of item states whose value could be converted to the 'referenceUnit'.
+     */
+    class Median extends DimensionalGroupFunction {
+
+        public Median(Unit<?> baseItemUnit) {
+            super(baseItemUnit);
+        }
+
+        @Override
+        public State calculate(@Nullable Set<Item> items) {
+            if (items != null) {
+                BigDecimal median = Statistics
+                        .median(toQuantityTypesOfUnit(items, systemUnit).stream().map(q -> q.toBigDecimal()).toList());
+                if (median != null) {
+                    return new QuantityType<>(median, systemUnit);
+                }
+            }
+            return UnDefType.UNDEF;
+        }
+    }
+
+    /**
+     * Calculates the sum of a set of item states whose value could be converted to the 'referenceUnit'.
+     *
+     * Uses the {@link QuanitityType.add()} method so the result is an incremental sum based on the 'referenceUnit'. As
+     * a general rule this class is instantiated with a 'referenceUnit' that is a "system unit" (which are zero based)
+     * so such incremental sum is in fact also an absolute sum. However the class COULD be instantiated with a "non-
+     * system unit" (e.g. °C, °F) in which case the result would be an incremental sum based on that unit.
+     *
      */
     class Sum extends DimensionalGroupFunction {
 
-        public Sum(Class<? extends Quantity<?>> dimension) {
-            super(dimension);
+        public Sum(Unit<?> baseItemUnit) {
+            super(baseItemUnit);
         }
 
         @Override
-        @SuppressWarnings({ "unchecked", "rawtypes" })
+        @SuppressWarnings("unchecked")
         public State calculate(@Nullable Set<Item> items) {
-            if (items == null || items.isEmpty()) {
-                return UnDefType.UNDEF;
-            }
-
-            QuantityType<?> sum = null;
-            for (Item item : items) {
-                if (isSameDimension(item)) {
-                    QuantityType itemState = item.getStateAs(QuantityType.class);
-                    if (itemState != null) {
-                        if (sum == null) {
-                            sum = itemState; // initialise the sum from the first item
-                        } else {
-                            itemState = itemState.toUnit(sum.getUnit());
-                            if (itemState != null) {
-                                sum = sum.add(itemState);
-                            }
-                        }
-                    }
+            if (items != null) {
+                @SuppressWarnings("rawtypes")
+                List<QuantityType> systemUnitQuantities = toQuantityTypesOfUnit(items, baseItemUnit);
+                if (!systemUnitQuantities.isEmpty()) {
+                    return systemUnitQuantities.stream().reduce(new QuantityType<>(0, baseItemUnit), QuantityType::add);
                 }
             }
-
-            return sum != null ? sum : UnDefType.UNDEF;
+            return UnDefType.UNDEF;
         }
     }
 
     /**
-     * This calculates the minimum value of all item states of {@link QuantityType}.
+     * Calculates the minimum of a set of item states whose value could be converted to the 'referenceUnit'.
      */
     class Min extends DimensionalGroupFunction {
 
-        public Min(Class<? extends Quantity<?>> dimension) {
-            super(dimension);
+        public Min(Unit<?> baseItemUnit) {
+            super(baseItemUnit);
         }
 
         @Override
-        @SuppressWarnings({ "unchecked", "rawtypes" })
         public State calculate(@Nullable Set<Item> items) {
-            if (items == null || items.isEmpty()) {
-                return UnDefType.UNDEF;
-            }
-
-            QuantityType<?> min = null;
-            for (Item item : items) {
-                if (isSameDimension(item)) {
-                    QuantityType itemState = item.getStateAs(QuantityType.class);
-                    if (itemState != null) {
-                        if (min == null
-                                || (min.getUnit().isCompatible(itemState.getUnit()) && min.compareTo(itemState) > 0)) {
-                            min = itemState;
-                        }
-                    }
+            if (items != null) {
+                @SuppressWarnings({ "unchecked", "rawtypes" })
+                Optional<QuantityType> min = toQuantityTypesOfUnit(items, systemUnit).stream()
+                        .min(QuantityType::compareTo);
+                if (min.isPresent()) {
+                    return min.get();
                 }
             }
-
-            return min != null ? min : UnDefType.UNDEF;
+            return UnDefType.UNDEF;
         }
     }
 
     /**
-     * This calculates the maximum value of all item states of {@link QuantityType}.
+     * Calculates the maximum of a set of item states whose value could be converted to the 'referenceUnit'.
      */
     class Max extends DimensionalGroupFunction {
 
-        public Max(Class<? extends Quantity<?>> dimension) {
-            super(dimension);
+        public Max(Unit<?> targetUnit) {
+            super(targetUnit);
         }
 
         @Override
-        @SuppressWarnings({ "unchecked", "rawtypes" })
         public State calculate(@Nullable Set<Item> items) {
-            if (items == null || items.isEmpty()) {
-                return UnDefType.UNDEF;
-            }
-
-            QuantityType<?> max = null;
-            for (Item item : items) {
-                if (isSameDimension(item)) {
-                    QuantityType itemState = item.getStateAs(QuantityType.class);
-                    if (itemState != null) {
-                        if (max == null
-                                || (max.getUnit().isCompatible(itemState.getUnit()) && max.compareTo(itemState) < 0)) {
-                            max = itemState;
-                        }
-                    }
+            if (items != null) {
+                @SuppressWarnings({ "unchecked", "rawtypes" })
+                Optional<QuantityType> max = toQuantityTypesOfUnit(items, systemUnit).stream()
+                        .max(QuantityType::compareTo);
+                if (max.isPresent()) {
+                    return max.get();
                 }
             }
-
-            return max != null ? max : UnDefType.UNDEF;
+            return UnDefType.UNDEF;
         }
     }
 }

bundles/org.openhab.core/src/test/java/org/openhab/core/library/types/QuantityTypeArithmeticGroupFunctionTest.java

@@ -15,7 +15,7 @@ package org.openhab.core.library.types;
 import static org.hamcrest.CoreMatchers.is;
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.number.IsCloseTo.closeTo;
-import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.*;
 import static org.junit.jupiter.params.provider.Arguments.arguments;
 
 import java.util.LinkedHashSet;
@@ -46,6 +46,9 @@ import org.openhab.core.items.GroupItem;
 import org.openhab.core.items.Item;
 import org.openhab.core.library.CoreItemFactory;
 import org.openhab.core.library.items.NumberItem;
+import org.openhab.core.library.unit.ImperialUnits;
+import org.openhab.core.library.unit.SIUnits;
+import org.openhab.core.library.unit.Units;
 import org.openhab.core.types.State;
 import org.openhab.core.types.UnDefType;
 import org.osgi.service.component.ComponentContext;
@@ -85,7 +88,7 @@ public class QuantityTypeArithmeticGroupFunctionTest {
         items.add(createNumberItem("TestItem4", Temperature.class, UnDefType.UNDEF));
         items.add(createNumberItem("TestItem5", Temperature.class, new QuantityType<>("122.41 °C")));
 
-        GroupFunction function = new QuantityTypeArithmeticGroupFunction.Sum(Temperature.class);
+        GroupFunction function = new QuantityTypeArithmeticGroupFunction.Sum(SIUnits.CELSIUS);
         State state = function.calculate(items);
 
         assertEquals(new QuantityType<>("234.95 °C"), state);
@@ -103,7 +106,7 @@ public class QuantityTypeArithmeticGroupFunctionTest {
         items.add(createNumberItem("TestItem4", Temperature.class, UnDefType.UNDEF));
         items.add(createNumberItem("TestItem5", Temperature.class, new QuantityType<>("395.56 K")));
 
-        GroupFunction function = new QuantityTypeArithmeticGroupFunction.Sum(Temperature.class);
+        GroupFunction function = new QuantityTypeArithmeticGroupFunction.Sum(SIUnits.CELSIUS);
         State state = function.calculate(items);
 
         assertEquals(new QuantityType<>("234.95 °C"), state);
@@ -119,7 +122,7 @@ public class QuantityTypeArithmeticGroupFunctionTest {
         items.add(createNumberItem("TestItem2", Temperature.class, UnDefType.NULL));
         items.add(createNumberItem("TestItem3", Pressure.class, new QuantityType<>("192.2 hPa")));
 
-        GroupFunction function = new QuantityTypeArithmeticGroupFunction.Sum(Temperature.class);
+        GroupFunction function = new QuantityTypeArithmeticGroupFunction.Sum(SIUnits.CELSIUS);
         State state = function.calculate(items);
 
         assertEquals(new QuantityType<>("23.54 °C"), state);
@@ -137,7 +140,7 @@ public class QuantityTypeArithmeticGroupFunctionTest {
         items.add(createNumberItem("TestItem4", Temperature.class, UnDefType.UNDEF));
         items.add(createNumberItem("TestItem5", Temperature.class, new QuantityType<>("300 °C")));
 
-        GroupFunction function = new QuantityTypeArithmeticGroupFunction.Avg(Temperature.class);
+        GroupFunction function = new QuantityTypeArithmeticGroupFunction.Avg(Units.KELVIN);
         State state = function.calculate(items);
 
         assertEquals(new QuantityType<>("200 °C"), state);
@@ -163,10 +166,11 @@ public class QuantityTypeArithmeticGroupFunctionTest {
         items.add(createNumberItem("TestItem4", Temperature.class, UnDefType.UNDEF));
         items.add(createNumberItem("TestItem5", Temperature.class, new QuantityType<>("294.15 K")));
 
-        GroupFunction function = new QuantityTypeArithmeticGroupFunction.Avg(Temperature.class);
+        GroupFunction function = new QuantityTypeArithmeticGroupFunction.Avg(Units.KELVIN);
         State state = function.calculate(items);
 
-        assertEquals(new QuantityType<>("55.33333333333333333333333333333334 °C"), state);
+        assertTrue(state instanceof QuantityType<?>);
+        assertEquals(328.48, ((QuantityType<?>) state).doubleValue(), 0.01);
     }
 
     @ParameterizedTest
@@ -179,12 +183,13 @@ public class QuantityTypeArithmeticGroupFunctionTest {
         items.add(createNumberItem("TestItem2", Temperature.class, UnDefType.NULL));
         items.add(createNumberItem("TestItem3", Pressure.class, new QuantityType<>("192.2 hPa")));
 
-        GroupFunction function = new QuantityTypeArithmeticGroupFunction.Avg(Temperature.class);
+        GroupFunction function = new QuantityTypeArithmeticGroupFunction.Avg(SIUnits.CELSIUS);
         State state = function.calculate(items);
 
         assertEquals(new QuantityType<>("23.54 °C"), state);
     }
 
+    @SuppressWarnings("rawtypes")
     static Stream<Arguments> medianTestSource() {
         return Stream.of( //
                 arguments( //
@@ -214,13 +219,14 @@ public class QuantityTypeArithmeticGroupFunctionTest {
 
     @ParameterizedTest
     @MethodSource("medianTestSource")
+    @SuppressWarnings({ "null", "rawtypes", "unchecked" })
     public void testMedianFunctionQuantityType(List<State> states, State expected) {
         AtomicInteger index = new AtomicInteger(1);
         Set<Item> items = states.stream()
                 .map(state -> createNumberItem("TestItem" + index.getAndIncrement(), Temperature.class, state))
                 .collect(Collectors.toSet());
 
-        GroupFunction function = new QuantityTypeArithmeticGroupFunction.Median(Temperature.class, null);
+        GroupFunction function = new QuantityTypeArithmeticGroupFunction.Median(SIUnits.CELSIUS);
         State state = function.calculate(items);
 
         assertEquals(state.getClass(), expected.getClass());
@@ -242,7 +248,7 @@ public class QuantityTypeArithmeticGroupFunctionTest {
         items.add(createNumberItem("TestItem4", Temperature.class, UnDefType.UNDEF));
         items.add(createNumberItem("TestItem5", Temperature.class, new QuantityType<>("300 °C")));
 
-        GroupFunction function = new QuantityTypeArithmeticGroupFunction.Max(Temperature.class);
+        GroupFunction function = new QuantityTypeArithmeticGroupFunction.Max(SIUnits.CELSIUS);
         State state = function.calculate(items);
 
         assertEquals(new QuantityType<>("300 °C"), state);
@@ -260,7 +266,7 @@ public class QuantityTypeArithmeticGroupFunctionTest {
         items.add(createNumberItem("TestItem4", Temperature.class, UnDefType.UNDEF));
         items.add(createNumberItem("TestItem5", Temperature.class, new QuantityType<>("294.15 K")));
 
-        GroupFunction function = new QuantityTypeArithmeticGroupFunction.Max(Temperature.class);
+        GroupFunction function = new QuantityTypeArithmeticGroupFunction.Max(SIUnits.CELSIUS);
         State state = function.calculate(items);
 
         assertEquals(new QuantityType<>("100 °C"), state);
@@ -276,7 +282,7 @@ public class QuantityTypeArithmeticGroupFunctionTest {
         items.add(createNumberItem("TestItem2", Temperature.class, UnDefType.NULL));
         items.add(createNumberItem("TestItem3", Pressure.class, new QuantityType<>("192.2 hPa")));
 
-        GroupFunction function = new QuantityTypeArithmeticGroupFunction.Max(Temperature.class);
+        GroupFunction function = new QuantityTypeArithmeticGroupFunction.Max(SIUnits.CELSIUS);
         State state = function.calculate(items);
 
         assertEquals(new QuantityType<>("23.54 °C"), state);
@@ -294,7 +300,7 @@ public class QuantityTypeArithmeticGroupFunctionTest {
         items.add(createNumberItem("TestItem4", Temperature.class, UnDefType.UNDEF));
         items.add(createNumberItem("TestItem5", Temperature.class, new QuantityType<>("300 °C")));
 
-        GroupFunction function = new QuantityTypeArithmeticGroupFunction.Min(Temperature.class);
+        GroupFunction function = new QuantityTypeArithmeticGroupFunction.Min(SIUnits.CELSIUS);
         State state = function.calculate(items);
 
         assertEquals(new QuantityType<>("100 °C"), state);
@@ -313,7 +319,7 @@ public class QuantityTypeArithmeticGroupFunctionTest {
         items.add(createNumberItem("TestItem5", Dimensionless.class, new QuantityType<>("0 %")));
         items.add(createNumberItem("TestItem6", Dimensionless.class, new QuantityType<>("0 %")));
 
-        GroupFunction function = new QuantityTypeArithmeticGroupFunction.Max(Dimensionless.class);
+        GroupFunction function = new QuantityTypeArithmeticGroupFunction.Max(Units.ONE);
         State state = function.calculate(items);
 
         assertEquals(new QuantityType<>("48 %"), state);
@@ -331,7 +337,7 @@ public class QuantityTypeArithmeticGroupFunctionTest {
         items.add(createNumberItem("TestItem4", Temperature.class, UnDefType.UNDEF));
         items.add(createNumberItem("TestItem5", Temperature.class, new QuantityType<>("294.15 K")));
 
-        GroupFunction function = new QuantityTypeArithmeticGroupFunction.Min(Temperature.class);
+        GroupFunction function = new QuantityTypeArithmeticGroupFunction.Min(SIUnits.CELSIUS);
         State state = function.calculate(items);
 
         assertEquals(new QuantityType<>("294.15 K"), state);
@@ -347,7 +353,7 @@ public class QuantityTypeArithmeticGroupFunctionTest {
         items.add(createNumberItem("TestItem2", Temperature.class, UnDefType.NULL));
         items.add(createNumberItem("TestItem3", Pressure.class, new QuantityType<>("192.2 hPa")));
 
-        GroupFunction function = new QuantityTypeArithmeticGroupFunction.Min(Temperature.class);
+        GroupFunction function = new QuantityTypeArithmeticGroupFunction.Min(SIUnits.CELSIUS);
         State state = function.calculate(items);
 
         assertEquals(new QuantityType<>("23.54 °C"), state);
@@ -362,7 +368,7 @@ public class QuantityTypeArithmeticGroupFunctionTest {
         items.add(createNumberItem("TestItem1", Power.class, new QuantityType<>("5 W")));
         items.add(createGroupItem("TestGroup1", Power.class, new QuantityType<>("5 W")));
 
-        GroupFunction function = new QuantityTypeArithmeticGroupFunction.Sum(Power.class);
+        GroupFunction function = new QuantityTypeArithmeticGroupFunction.Sum(Units.WATT);
         State state = function.calculate(items);
 
         assertEquals(new QuantityType<>("10 W"), state);
@@ -380,4 +386,190 @@ public class QuantityTypeArithmeticGroupFunctionTest {
         item.setState(state);
         return item;
     }
+
+    @ParameterizedTest
+    @MethodSource("locales")
+    public void testSumFunctionQuantityTypeDifferentUnitsBaseKelvin(Locale locale) {
+        Locale.setDefault(locale);
+
+        Set<Item> items = new LinkedHashSet<>();
+        items.add(createNumberItem("TestItem1", Temperature.class, new QuantityType<>("23.54 °C")));
+        items.add(createNumberItem("TestItem2", Temperature.class, UnDefType.NULL));
+        items.add(createNumberItem("TestItem3", Temperature.class, new QuantityType<>("192.2 °F")));
+        items.add(createNumberItem("TestItem4", Temperature.class, UnDefType.UNDEF));
+        items.add(createNumberItem("TestItem5", Temperature.class, new QuantityType<>("395.56 K")));
+
+        GroupFunction function = new QuantityTypeArithmeticGroupFunction.Sum(Units.KELVIN);
+        State state = function.calculate(items);
+
+        assertEquals(new QuantityType<>("1054.40 K"), state);
+    }
+
+    @ParameterizedTest
+    @MethodSource("locales")
+    public void testAvgFunctionQuantityTypeDifferentUnitsBaseKelvin(Locale locale) {
+        Locale.setDefault(locale);
+
+        Set<Item> items = new LinkedHashSet<>();
+        items.add(createNumberItem("TestItem1", Temperature.class, new QuantityType<>("100 °C")));
+        items.add(createNumberItem("TestItem2", Temperature.class, UnDefType.NULL));
+        items.add(createNumberItem("TestItem3", Temperature.class, new QuantityType<>("113 °F")));
+        items.add(createNumberItem("TestItem4", Temperature.class, UnDefType.UNDEF));
+        items.add(createNumberItem("TestItem5", Temperature.class, new QuantityType<>("294.15 K")));
+
+        GroupFunction function = new QuantityTypeArithmeticGroupFunction.Avg(Units.KELVIN);
+        State state = function.calculate(items);
+
+        assertTrue(state instanceof QuantityType<?>);
+        assertEquals(328.48, ((QuantityType<?>) state).doubleValue(), 0.01);
+    }
+
+    @ParameterizedTest
+    @MethodSource("locales")
+    public void testMaxFunctionQuantityTypeDifferentUnitsBaseKelvin(Locale locale) {
+        Locale.setDefault(locale);
+
+        Set<Item> items = new LinkedHashSet<>();
+        items.add(createNumberItem("TestItem1", Temperature.class, new QuantityType<>("100 °C")));
+        items.add(createNumberItem("TestItem2", Temperature.class, UnDefType.NULL));
+        items.add(createNumberItem("TestItem3", Temperature.class, new QuantityType<>("113 °F")));
+        items.add(createNumberItem("TestItem4", Temperature.class, UnDefType.UNDEF));
+        items.add(createNumberItem("TestItem5", Temperature.class, new QuantityType<>("294.15 K")));
+
+        GroupFunction function = new QuantityTypeArithmeticGroupFunction.Max(Units.KELVIN);
+        State state = function.calculate(items);
+
+        assertEquals(new QuantityType<>("100 °C"), state);
+    }
+
+    @ParameterizedTest
+    @MethodSource("locales")
+    public void testMinFunctionQuantityTypeDifferentUnitsBaseKelvin(Locale locale) {
+        Locale.setDefault(locale);
+
+        Set<Item> items = new LinkedHashSet<>();
+        items.add(createNumberItem("TestItem1", Temperature.class, new QuantityType<>("100 °C")));
+        items.add(createNumberItem("TestItem2", Temperature.class, UnDefType.NULL));
+        items.add(createNumberItem("TestItem3", Temperature.class, new QuantityType<>("113 °F")));
+        items.add(createNumberItem("TestItem4", Temperature.class, UnDefType.UNDEF));
+        items.add(createNumberItem("TestItem5", Temperature.class, new QuantityType<>("294.15 K")));
+
+        GroupFunction function = new QuantityTypeArithmeticGroupFunction.Min(Units.KELVIN);
+        State state = function.calculate(items);
+
+        assertEquals(new QuantityType<>("294.15 K"), state);
+    }
+
+    @ParameterizedTest
+    @MethodSource("locales")
+    public void testSumFunctionColorTemperatureDifferentUnitsBaseKelvin(Locale locale) {
+        Locale.setDefault(locale);
+
+        Set<Item> items = new LinkedHashSet<>();
+        items.add(createNumberItem("TestItem1", Temperature.class, QuantityType.valueOf(2000, Units.KELVIN)));
+        items.add(createNumberItem("TestItem2", Temperature.class, UnDefType.NULL));
+        items.add(createNumberItem("TestItem3", Temperature.class, QuantityType.valueOf(1726.85, SIUnits.CELSIUS)));
+        items.add(createNumberItem("TestItem4", Temperature.class, QuantityType.valueOf(500, Units.MIRED)));
+        items.add(createNumberItem("TestItem5", Temperature.class,
+                QuantityType.valueOf(3140.33, ImperialUnits.FAHRENHEIT)));
+
+        GroupFunction function = new QuantityTypeArithmeticGroupFunction.Sum(Units.KELVIN);
+        State state = function.calculate(items);
+
+        assertEquals(new QuantityType<>("8000 K"), state);
+    }
+
+    @ParameterizedTest
+    @MethodSource("locales")
+    public void testAvgFunctionQuantityTypeColorTempDifferentUnitsBaseKelvin(Locale locale) {
+        Locale.setDefault(locale);
+
+        Set<Item> items = new LinkedHashSet<>();
+        items.add(createNumberItem("TestItem1", Temperature.class, QuantityType.valueOf(2000, Units.KELVIN)));
+        items.add(createNumberItem("TestItem2", Temperature.class, UnDefType.NULL));
+        items.add(createNumberItem("TestItem3", Temperature.class, QuantityType.valueOf(1726.85, SIUnits.CELSIUS)));
+        items.add(createNumberItem("TestItem4", Temperature.class, QuantityType.valueOf(500, Units.MIRED)));
+        items.add(createNumberItem("TestItem5", Temperature.class,
+                QuantityType.valueOf(3140.33, ImperialUnits.FAHRENHEIT)));
+
+        GroupFunction function = new QuantityTypeArithmeticGroupFunction.Avg(Units.KELVIN);
+        State state = function.calculate(items);
+
+        assertEquals(new QuantityType<>("2000 K"), state);
+    }
+
+    @ParameterizedTest
+    @MethodSource("locales")
+    public void testAvgFunctionQuantityTypeColorTempDifferentUnitsBaseMirek(Locale locale) {
+        Locale.setDefault(locale);
+
+        Set<Item> items = new LinkedHashSet<>();
+        items.add(createNumberItem("TestItem1", Temperature.class, QuantityType.valueOf(2000, Units.KELVIN)));
+        items.add(createNumberItem("TestItem2", Temperature.class, UnDefType.NULL));
+        items.add(createNumberItem("TestItem3", Temperature.class, QuantityType.valueOf(1726.85, SIUnits.CELSIUS)));
+        items.add(createNumberItem("TestItem4", Temperature.class, QuantityType.valueOf(500, Units.MIRED)));
+        items.add(createNumberItem("TestItem5", Temperature.class,
+                QuantityType.valueOf(3140.33, ImperialUnits.FAHRENHEIT)));
+
+        GroupFunction function = new QuantityTypeArithmeticGroupFunction.Avg(Units.MIRED);
+        State state = function.calculate(items);
+
+        assertEquals(new QuantityType<>("2000 K"), state);
+    }
+
+    @ParameterizedTest
+    @MethodSource("locales")
+    public void testMinFunctionColorTemperatureDifferentUnitsBaseKelvin(Locale locale) {
+        Locale.setDefault(locale);
+
+        Set<Item> items = new LinkedHashSet<>();
+        items.add(createNumberItem("TestItem1", Temperature.class, QuantityType.valueOf(1999, Units.KELVIN)));
+        items.add(createNumberItem("TestItem2", Temperature.class, UnDefType.NULL));
+        items.add(createNumberItem("TestItem3", Temperature.class, QuantityType.valueOf(1726.85, SIUnits.CELSIUS)));
+        items.add(createNumberItem("TestItem4", Temperature.class, QuantityType.valueOf(500, Units.MIRED)));
+        items.add(createNumberItem("TestItem5", Temperature.class,
+                QuantityType.valueOf(3140.33, ImperialUnits.FAHRENHEIT)));
+
+        GroupFunction function = new QuantityTypeArithmeticGroupFunction.Min(Units.KELVIN);
+        State state = function.calculate(items);
+
+        assertEquals(new QuantityType<>("1999 K"), state);
+    }
+
+    @ParameterizedTest
+    @MethodSource("locales")
+    public void testMaxFunctionColorTemperatureDifferentUnitsBaseKelvin(Locale locale) {
+        Locale.setDefault(locale);
+
+        Set<Item> items = new LinkedHashSet<>();
+        items.add(createNumberItem("TestItem1", Temperature.class, QuantityType.valueOf(2001, Units.KELVIN)));
+        items.add(createNumberItem("TestItem2", Temperature.class, UnDefType.NULL));
+        items.add(createNumberItem("TestItem3", Temperature.class, QuantityType.valueOf(1726.85, SIUnits.CELSIUS)));
+        items.add(createNumberItem("TestItem4", Temperature.class, QuantityType.valueOf(500, Units.MIRED)));
+        items.add(createNumberItem("TestItem5", Temperature.class,
+                QuantityType.valueOf(3140.33, ImperialUnits.FAHRENHEIT)));
+
+        GroupFunction function = new QuantityTypeArithmeticGroupFunction.Max(Units.KELVIN);
+        State state = function.calculate(items);
+
+        assertEquals(new QuantityType<>("2001 K"), state);
+    }
+
+    @ParameterizedTest
+    @MethodSource("locales")
+    public void testSumFunctionQuantityTypeDifferentUnitsBaseWatt(Locale locale) {
+        Locale.setDefault(locale);
+
+        Set<Item> items = new LinkedHashSet<>();
+        items.add(createNumberItem("TestItem1", Power.class, new QuantityType<>("1 W")));
+        items.add(createNumberItem("TestItem2", Temperature.class, UnDefType.NULL));
+        items.add(createNumberItem("TestItem3", Temperature.class, new QuantityType<>("192.2 °F")));
+        items.add(createNumberItem("TestItem4", Temperature.class, UnDefType.UNDEF));
+        items.add(createNumberItem("TestItem5", Power.class, new QuantityType<>("3000 mW")));
+
+        GroupFunction function = new QuantityTypeArithmeticGroupFunction.Sum(Units.WATT);
+        State state = function.calculate(items);
+
+        assertEquals(new QuantityType<>("4 W"), state);
+    }
 }