ArrayUtilsTest.java

package org.dayatang.utils;

import org.dayatang.utils.beans.Item;
import org.junit.Test;

import static org.junit.Assert.*;

public class ArrayUtilsTest {

    @Test
    public void testSubstract() {
        Item[] items = {
            new Item(1, "A"),
            new Item(2, "B"),
            new Item(1, "C")
        };
        assertArrayEquals(new Object[]{1, 2, 1}, ArrayUtils.substract(items, "id"));
        assertArrayEquals(new Object[]{"A", "B", "C"}, ArrayUtils.substract(items, "name"));
    }

    @Test
    public void testSubstractEmpty() {
        assertEquals(ArrayUtils.substract(new Item[]{}, "name").length, 0);
    }

    @Test
    public void testSubstractSingleElement() {
        Item[] items = {
            new Item(1, "A")
        };
        assertArrayEquals(new Object[]{1}, ArrayUtils.substract(items, "id"));
    }

    @Test(expected = IllegalArgumentException.class)
    public void testPropertyNotExists() {
        Item[] items = {
            new Item(1, "A"),
            new Item(2, "B"),
            new Item(1, "C")
        };
        ArrayUtils.substract(items, "birthday");
    }
    
    @Test
    public void testJoin() {
        Item[] items = {
            new Item(1, "A"),
            new Item(2, "B"),
            new Item(1, "C")
        };
        String separator = ", ";
        String result = ArrayUtils.join(items, "id", separator);
        assertEquals("1, 2, 1", result);
    }

    @Test
    public void testJoinNull() {
        String separator = ", ";
        Item[] items = null;
        String result = ArrayUtils.join(items, "id", separator);
        assertTrue(result.isEmpty());
    }

    @Test
    public void testJoinEmpty() {
        Item[] items = {};
        String separator = ", ";
        String result = ArrayUtils.join(items, "id", separator);
        assertTrue(result.isEmpty());
    }

    @Test
    public void testJoinSingleElement() {
        Item[] items = {
            new Item(1, "A")
        };
        String separator = ", ";
        String result = ArrayUtils.join(items, "name", separator);
        assertEquals("A", result);
    }
}