[mqtt.homeassistant] sensors with a state_class are numeric (#13398)

see reference in code comment, but a measurement sensor is assumed to
be numeric, even if it doesn't have a unit

Signed-off-by: Cody Cutrer <cody@cutrer.us>

bundles/org.openhab.binding.mqtt.homeassistant/src/main/java/org/openhab/binding/mqtt/homeassistant/internal/component/Sensor.java

@@ -49,6 +49,8 @@ public class Sensor extends AbstractComponent<Sensor.ChannelConfiguration> {
         protected @Nullable String unitOfMeasurement;
         @SerializedName("device_class")
         protected @Nullable String deviceClass;
+        @SerializedName("state_class")
+        protected @Nullable String stateClass;
         @SerializedName("force_update")
         protected boolean forceUpdate = false;
         @SerializedName("expire_after")
@@ -70,9 +72,14 @@ public class Sensor extends AbstractComponent<Sensor.ChannelConfiguration> {
 
         Value value;
         String uom = channelConfiguration.unitOfMeasurement;
+        String sc = channelConfiguration.stateClass;
 
         if (uom != null && !uom.isBlank()) {
             value = new NumberValue(null, null, null, UnitUtils.parseUnit(uom));
+        } else if (sc != null && !sc.isBlank()) {
+            // see state_class at https://developers.home-assistant.io/docs/core/entity/sensor#properties
+            // > If not None, the sensor is assumed to be numerical
+            value = new NumberValue(null, null, null, null);
         } else {
             value = new TextValue();
         }

bundles/org.openhab.binding.mqtt.homeassistant/src/test/java/org/openhab/binding/mqtt/homeassistant/internal/component/SensorTests.java

@@ -20,6 +20,7 @@ import java.util.Set;
 import org.eclipse.jdt.annotation.NonNullByDefault;
 import org.junit.jupiter.api.Test;
 import org.openhab.binding.mqtt.generic.values.NumberValue;
+import org.openhab.binding.mqtt.generic.values.TextValue;
 import org.openhab.core.library.types.QuantityType;
 import org.openhab.core.library.unit.Units;
 import org.openhab.core.types.UnDefType;
@@ -79,6 +80,58 @@ public class SensorTests extends AbstractComponentTests {
         waitForAssert(() -> assertState(component, Sensor.SENSOR_CHANNEL_ID, UnDefType.UNDEF), 10000, 200);
     }
 
+    @Test
+    public void testMeasurementStateClass() throws InterruptedException {
+        // @formatter:off
+        var component = discoverComponent(configTopicToMqtt(CONFIG_TOPIC),
+                "{ " +
+                        "  \"device\": { " +
+                        "    \"identifiers\": [ " +
+                        "      \"zigbee2mqtt_0x0000000000000000\" " +
+                        "    ], " +
+                        "    \"manufacturer\": \"Sensors inc\", " +
+                        "    \"model\": \"Sensor\", " +
+                        "    \"name\": \"Sensor\", " +
+                        "    \"sw_version\": \"Zigbee2MQTT 1.18.2\" " +
+                        "  }, " +
+                        "  \"name\": \"sensor1\", " +
+                        "  \"expire_after\": \"1\", " +
+                        "  \"force_update\": \"true\", " +
+                        "  \"state_class\": \"measurement\", " +
+                        "  \"state_topic\": \"zigbee2mqtt/sensor/state\", " +
+                        "  \"unique_id\": \"sn1\" " +
+                        "}");
+        // @formatter:on
+
+        assertChannel(component, Sensor.SENSOR_CHANNEL_ID, "zigbee2mqtt/sensor/state", "", "sensor1",
+                NumberValue.class);
+    }
+
+    @Test
+    public void testNonNumericSensor() throws InterruptedException {
+        // @formatter:off
+        var component = discoverComponent(configTopicToMqtt(CONFIG_TOPIC),
+                "{ " +
+                        "  \"device\": { " +
+                        "    \"identifiers\": [ " +
+                        "      \"zigbee2mqtt_0x0000000000000000\" " +
+                        "    ], " +
+                        "    \"manufacturer\": \"Sensors inc\", " +
+                        "    \"model\": \"Sensor\", " +
+                        "    \"name\": \"Sensor\", " +
+                        "    \"sw_version\": \"Zigbee2MQTT 1.18.2\" " +
+                        "  }, " +
+                        "  \"name\": \"sensor1\", " +
+                        "  \"expire_after\": \"1\", " +
+                        "  \"force_update\": \"true\", " +
+                        "  \"state_topic\": \"zigbee2mqtt/sensor/state\", " +
+                        "  \"unique_id\": \"sn1\" " +
+                        "}");
+        // @formatter:on
+
+        assertChannel(component, Sensor.SENSOR_CHANNEL_ID, "zigbee2mqtt/sensor/state", "", "sensor1", TextValue.class);
+    }
+
     @Override
     protected Set<String> getConfigTopics() {
         return Set.of(CONFIG_TOPIC);