import org.junit.Test;
//import src.main.java.BasicStatistic;

import static org.junit.Assert.*;

public class BasicStatisticTest {

    @Test
    public void numberOfDataItemsShouldBeZeroWhenNoneItemsWereAdded() {
        // arrange
        BasicStatistic basicStatistic = new BasicStatistic();

        // act
        int amountOfItemsInDataList = basicStatistic.numberOfDataItems();

        // assert
        assertEquals(0, amountOfItemsInDataList);
    }

    @Test
    public void numberOfDataItemsShouldBeMoreThanZeroAfterAdding() {
        // arrange
        BasicStatistic basicStatistic = new BasicStatistic();

        // act
        basicStatistic.addDoubleToData(new Double(12));
        int amountOfItemsInDataList = basicStatistic.numberOfDataItems();

        // assert
        assertEquals(1, amountOfItemsInDataList);
    }

    @Test
    public void clearDataShouldSetDataListToBeEmpty() {
        // arrange
        BasicStatistic basicStatistic = new BasicStatistic();

        // act
        basicStatistic.addDoubleToData(new Double(12));
        basicStatistic.addDoubleToData(new Double(13));
        basicStatistic.clearData();;

        int amountOfItemsInDataList = basicStatistic.numberOfDataItems();

        // assert
        assertEquals(0, amountOfItemsInDataList);
    }

    @Test
    public void addingItemsToDataListShouldIncreaseAmountOfItems() {
        // arrange
        BasicStatistic basicStatistic = new BasicStatistic();

        // act
        int beforeAddedItemsInDataListCount = 0;
        basicStatistic.addDoubleToData(new Double(11));
        basicStatistic.addDoubleToData(new Double(2));
        basicStatistic.addDoubleToData(new Double(9));
        int afterAddedItemsToDataListCount = basicStatistic.numberOfDataItems();

        // assert
        assertEquals(beforeAddedItemsInDataListCount + 3, afterAddedItemsToDataListCount);
    }

    @Test
    public void sumShouldReturnTotalSumOfAllItemsInDataList() {
        // arrange
        BasicStatistic basicStatistic = new BasicStatistic();

        // act
        basicStatistic.addDoubleToData(new Double(14));
        basicStatistic.addDoubleToData(new Double(22));
        Double sumOfAllItemsInDataList = basicStatistic.sum();

        // assert
        assertEquals(36, sumOfAllItemsInDataList.doubleValue(), 0.5);
    }
}