java - @Before/@BeforeClass 似乎不起作用，对象指示为空

Question

我正在学习junit，一开始就出现了问题。

一开始我想初始化将在测试中使用的对象。但是@BeforeClass 不会那样做。

public class InitTests {
private Croupier croupier;
private Player p1, p2;
@BeforeClass
public void setUp() {
    croupier = new Croupier();
    croupier.PlayersInit(5, 100);
    p1 = croupier.getPlayer(0);
    p2 = croupier.getPlayer(1);
} @Test // p1,p2, croupier = null, have no idea why.
public void PlayerInitTest() {
    assertEquals(0, p1.getId());
    assertEquals(1, p2.getId());
}}

其他类:

public class Player {

private ArrayList<Card> hand = new ArrayList<>();
private int coins = 0;
private static int playerNumber = 0;
private int id;
private boolean inGame = true;

public Player(int coins) {
    this.coins = coins;
    id = ++playerNumber;
}

public int addCoins(int amount) {
    coins+=amount;
    return amount;
}

public int substractCoins(int substract) {
    coins-=substract;
    return substract;
}

public int getCoins() {
    return coins;
}

public int getId() {
    return id;
}

public boolean isInGame() {
    return inGame;
}

public void setGameStatus(boolean status) {
    if(getCoins() < 0 )
        inGame = false;
    else 
        inGame = status;
}

public void clearHand() {
    hand.clear();
}}

public class Croupier {

private String name;
private ArrayList<Card> deck = new ArrayList<>();
private ArrayList<Player> allPlayers = new ArrayList<>();
private ArrayList<Player> actual = new ArrayList<>();
private int stack = 0;
private int bigPlayerStack = 0;
private int smallPlayerStack = 0;

public Croupier() {
    System.out.println("tutej.");
}

public Croupier CroupierInit() {
    // static
    PlayersInit(5, 100);

    return new Croupier();
}

private void CreateDeck() {
    String[] suits = { "hearts", "spades", "diamonds", "clubs" };

    for (int i = 0; i < suits.length; i++)
        for (int j = 2; j < 15; j++)
            deck.add(new Card(j, suits[i]));

}

private void DeckShuffle() {
    Collections.shuffle(deck);
}

public boolean TurnPlayed() {
    if (!preparedGame())
        return false;

    return true;

}

public void StartGame() {
    preparedGame();
    System.out.println("Game ended.");
}

public boolean preparedGame() {
    clearTable();

    if(!setActualPlayers()) 
        return false;

    setSmallAndBig();
    takeFromSmallAndBig();
    CreateDeck();
    DeckShuffle();

    return true;
}

// set players who are playing
public boolean setActualPlayers() {
    for (Player e : allPlayers)
        if (e.isInGame())
            actual.add(e);

    if (actual.size() < 2)
        return false;

    return true;
}

// take coisn from small and big blind
public void takeFromSmallAndBig() {
    stack += actual.get(bigPlayerStack).substractCoins(20);
    stack += actual.get(smallPlayerStack).substractCoins(10);
}

// set who has small or big blind
public void setSmallAndBig() {
    bigPlayerStack++;
    if (bigPlayerStack > actual.size())
        bigPlayerStack = 0;

    smallPlayerStack = bigPlayerStack - 1;

    if(smallPlayerStack < 0 )
        smallPlayerStack = actual.size() -1;
}

// clear table before game
public void clearTable() {
    actual.clear();
    for (Player e : allPlayers)
        e.clearHand();
}

public void PlayersInit(int numberOfPlayers, int coins) {
    for (int i = 0; i < numberOfPlayers; i++) {
        allPlayers.add(new Player(coins));
    }
}

public Player getPlayer(int index) {
    return allPlayers.get(index);
}}

我确信这些测试是正确的，因为当我将 setUp 方法(来自该方法的代码)放入 @Test 中时，它就可以正常工作。我希望这是一个简单的语法问题，作为初学者目前无法设置。

问候。

Answer 1

您的测试类混合使用了 JUnit 4 和 5 注释。

JUnit 5 API 与以前版本的库不兼容，并定义了一组新的注释。假设您的测试执行，您可能正在使用 JUnit 5 启动器，因此需要使用来自 org.junit.jupiter.api 的注释。包。

如果您想使用 JUnit 5
尝试使用 @org.junit.jupiter.api.BeforeEach 或 @org.junit.jupiter.api.BeforeAll，后者使用静态方法。它们的语义定义为 here .

如果您想使用 JUnit 4
您需要将所有注释恢复为 JUnit 4 - 这意味着使用 org.junit.Test。
您的 JUnit 启动器需要针对 JUnit 4 进行配置。