TestUser.java

package com.nicewuerfel.blockown;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertNotSame;
import static org.junit.Assert.assertSame;
import static org.junit.Assert.assertTrue;

import org.junit.BeforeClass;
import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.ExpectedException;

import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.UUID;

public class TestUser {

  private static List<UUID> ids;

  @BeforeClass
  public static void init() {
    Set<UUID> ids = new HashSet<>(40);
    for (int i = 0; i < 20; i++) {
      if (!ids.add(UUID.randomUUID())) {
        i--;
      }
    }
    TestUser.ids = Collections.unmodifiableList(listFromSet(ids));
  }

  private static <T> List<T> listFromSet(Set<T> ids) {
    List<T> list = new ArrayList<>(ids.size());
    list.addAll(ids);
    return list;
  }

  @Rule
  public ExpectedException expected = ExpectedException.none();

  @Test
  public void testIntegrity() {
    assertEquals(0, User.class.getConstructors().length);

    User u1 = User.getInstance(ids.get(0));
    User u1_2 = User.getInstance(ids.get(0));
    User u2 = User.getInstance(ids.get(1));

    assertSame(u1, u1_2);
    assertNotSame(u1, u2);

    User u2_2 = User.getInstance(ids.get(1), null);
    assertSame(u2_2, u2);

    expected.expect(NullPointerException.class);
    @SuppressWarnings("unused")
    User noob = User.getInstance(null);
  }

  @Test
  public void testEquals() {
    User u1 = User.getInstance(ids.get(0));
    User u1_2 = User.getInstance(ids.get(0));
    User u1_3 = User.getInstance(ids.get(0));
    User u2 = User.getInstance(ids.get(1));

    // Integrity
    assertFalse(u1.equals(u2));
    assertFalse(u2.equals(u1));

    // Reflexivity
    assertTrue(u1.equals(u1));

    // Transivity
    assertTrue(u1.equals(u1_2));
    assertTrue(u1_2.equals(u1_3));
    assertTrue(u1.equals(u1_3));

    // Symmetry
    assertTrue(u1.equals(u1_2));
    assertTrue(u1_2.equals(u1));
    assertFalse(u1.equals(u2));
    assertFalse(u2.equals(u1));
  }

  @Test
  public void testHashCode() {
    User u1 = User.getInstance(ids.get(0));
    User u1_2 = User.getInstance(ids.get(0));
    User u2 = User.getInstance(ids.get(1));

    assertEquals(u1.hashCode(), u1_2.hashCode());
    assertEquals(u2.hashCode(), u2.hashCode());
  }

  @Test
  public void testToString() {
    // Just to make sure no NullPointers are thrown
    User u1 = User.getInstance(ids.get(0));
    u1.toString();
  }
}