ArrayListTest.java

package com.examplehub.datastructures.array;

import static org.junit.jupiter.api.Assertions.*;

import org.junit.jupiter.api.Test;

class ArrayListTest {
  @Test
  void testArrayList() {
    ArrayList<String> arrayList = new ArrayList<>(10);
    assertTrue(arrayList.isEmpty());
    assertEquals(0, arrayList.size());
    assertEquals("[]", arrayList.toString());

    try {
      arrayList.remove();
      fail(); /* this should will not happen */
    } catch (IndexOutOfBoundsException e) {
      assertTrue(true); /* this should will happen */
    }

    for (int i = 1; i <= 5; ++i) {
      assertTrue(arrayList.add(i + ""));
    }
    assertEquals("[1, 2, 3, 4, 5]", arrayList.toString());

    arrayList.add(0, "0");
    arrayList.add(4, "444");
    assertEquals("[0, 1, 2, 3, 444, 4, 5]", arrayList.toString());

    assertEquals("444", arrayList.remove(4));
    assertEquals("0", arrayList.remove(0));
    assertEquals(5, arrayList.size());
    assertEquals("[1, 2, 3, 4, 5]", arrayList.toString());

    arrayList.clear();
    assertEquals(0, arrayList.size());
    assertTrue(arrayList.isEmpty());
  }

  @Test
  void testGrow() {
    ArrayList<String> arrayList = new ArrayList<>(5);
    for (int i = 1; i <= 7; i++) {
      arrayList.add(i + "");
    }
    assertEquals(7, arrayList.size());
    assertEquals("[1, 2, 3, 4, 5, 6, 7]", arrayList.toString());
  }

  @Test
  void testRemove() {
    ArrayList<String> arrayList = new ArrayList<>();
    for (int i = 1; i <= 5; i++) {
      arrayList.add("" + i);
    }
    arrayList.add("3");
    arrayList.add(2, "3");
    assertEquals("[1, 2, 3, 3, 4, 5, 3]", arrayList.toString());

    arrayList.remove("3");
    assertEquals("[1, 2, 4, 5]", arrayList.toString());
  }
}