java-tutorials/libraries/src/test/java/com/baeldung/measurement/WaterTankTests.java

package com.baeldung.measurement;

import javax.measure.Quantity;
import javax.measure.quantity.Area;
import javax.measure.quantity.Length;
import javax.measure.quantity.Pressure;
import javax.measure.quantity.Volume;

import javax.measure.Unit;
import javax.measure.UnitConverter;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;
import org.junit.Test;

import com.baeldung.measurement.WaterTank;

import tec.units.ri.format.SimpleUnitFormat;
import tec.units.ri.quantity.Quantities;
import tec.units.ri.unit.MetricPrefix;
import static tec.units.ri.unit.Units.*;

public class WaterTankTests {

    @Test
    public void givenQuantity_whenGetUnitAndConvertValue_thenSuccess() {
        WaterTank waterTank = new WaterTank();
        waterTank.setCapacityMeasure(Quantities.getQuantity(9.2, LITRE));
        assertEquals(LITRE, waterTank.getCapacityMeasure().getUnit());

        Quantity<Volume> waterCapacity = waterTank.getCapacityMeasure();
        double volumeInLitre = waterCapacity.getValue().doubleValue();
        assertEquals(9.2, volumeInLitre, 0.0f);

        double volumeInMilliLitre = waterCapacity.to(MetricPrefix.MILLI(LITRE)).getValue().doubleValue();
        assertEquals(9200.0, volumeInMilliLitre, 0.0f);

        // compilation error
        // volumeInMilliLitre = waterCapacity.to(MetricPrefix.MILLI(KILOGRAM));

        Unit<Length> Kilometer = MetricPrefix.KILO(METRE);

        // compilation error
        // Unit<Length> Centimeter = MetricPrefix.CENTI(LITRE);
    }

    @Test
    public void givenUnit_whenAlternateUnit_ThenGetAlternateUnit() {

        Unit<Pressure> PASCAL = NEWTON.divide(METRE.pow(2)).alternate("Pa").asType(Pressure.class);
        assertTrue(SimpleUnitFormat.getInstance().parse("Pa").equals(PASCAL));
    }

    @Test
    public void givenUnit_whenProduct_ThenGetProductUnit() {
        Unit<Area> squareMetre = METRE.multiply(METRE).asType(Area.class);
        Quantity<Length> line = Quantities.getQuantity(2, METRE);
        assertEquals(line.multiply(line).getUnit(), squareMetre);
    }

    @Test
    public void givenMeters_whenConvertToKilometer_ThenConverted() {
        double distanceInMeters = 50.0;
        UnitConverter metreToKilometre = METRE.getConverterTo(MetricPrefix.KILO(METRE));
        double distanceInKilometers = metreToKilometre.convert(distanceInMeters);
        assertEquals(0.05, distanceInKilometers, 0.00f);
    }

    @Test
    public void givenSymbol_WhenCompareToSystemUnit_ThenSuccess() {
        assertTrue(SimpleUnitFormat.getInstance().parse("kW").equals(MetricPrefix.KILO(WATT)));
        assertTrue(SimpleUnitFormat.getInstance().parse("ms").equals(SECOND.divide(1000)));
    }

    @Test
    public void givenUnits_WhenAdd_ThenSuccess() {
        Quantity<Length> total = Quantities.getQuantity(2, METRE).add(Quantities.getQuantity(3, METRE));
        assertEquals(total.getValue().intValue(), 5);

        // compilation error
        // Quantity<Length> total = Quantities.getQuantity(2, METRE).add(Quantities.getQuantity(3, LITRE));

        Quantity<Length> totalKm = Quantities.getQuantity(2, METRE).add(Quantities.getQuantity(3, MetricPrefix.KILO(METRE)));
        assertEquals(totalKm.getValue().intValue(), 3002);
    }
}