junit java 错误消息的参数化测试构造函数：测试 class 应该只有一个 public 零参数构造函数

Question

对于我尝试创建的这个参数化测试用例，我确实需要一些帮助。无论我创建哪种构造函数，IDE 都会给出错误消息。这是我的代码：

@RunWith(Parameterized.class)
public class SolverTest {
    final static File folder = new File("C:\Users\Azizam\IdeaProjects\EightPuzzle\src\ModifiedTests");
    final static String destFolder = "C:\Users\Azizam\IdeaProjects\EightPuzzle\src\testresults";
    final static ArrayList<Object[][]> filesList = new ArrayList<>();
    final Object currentBoard = new Object();

    @Parameterized.Parameters
    public static Iterable<Object[][]> data() {
        String path = "";
        int counter = 0;
        for (final File fileEntry : folder.listFiles()) {
            //System.out.println("processing file: " + fileEntry.getName())
            counter++;
            if (counter == 20) break;
            path = destFolder + fileEntry;
            In in = new In(fileEntry.getAbsolutePath());
            int n = in.readInt();
            int moves = in.readInt();
            int[][] tiles = new int[n][n];
            for (int i = 0; i < n; i++)
                for (int j = 0; j < n; j++)
                    tiles[i][j] = in.readInt();
            Board b = new Board(tiles);
            Object[][] fileList = new Object[][]{{b, moves}};
            filesList.add(fileList);
        }
        return filesList;
    }

    @Parameterized.Parameter(0)
    private Board board;
    @Parameterized.Parameter(1)
    private int expectedNumberOfMoves;

    public SolverTest(Board board, int expectedNumberOfMoves) {
        this.board = board;
        this.expectedNumberOfMoves = expectedNumberOfMoves;
    }


    @Test
    public void test() {
        assertEquals(expectedNumberOfMoves, new Solver(board).moves());
    }

}

我尝试了不同的方法来创建 1 个参数、2 个和无参数构造函数。但我从未见过此类问题或解决方案。我正在关注 this link and this 教程。这是我的第一个参数化测试，调试似乎也没有为我提供太多帮助。我还看到了 these 链接，但它们没有帮助。我也可以在 GitHub 或 gist 上提供项目其余部分的代码。我确实通过正确创建 fileList 来调试我的代码，但我对之后发生的事情或需要发生的事情知之甚少。以下是错误的摘录：

java.lang.Exception: Test class should have exactly one public zero-argument constructor

    at org.junit.runners.BlockJUnit4ClassRunner.validateZeroArgConstructor(BlockJUnit4ClassRunner.java:171)
    at org.junit.runners.parameterized.BlockJUnit4ClassRunnerWithParameters.validateConstructor(BlockJUnit4ClassRunnerWithParameters.java:90)
    at org.junit.runners.BlockJUnit4ClassRunner.collectInitializationErrors(BlockJUnit4ClassRunner.java:127)
    at org.junit.runners.ParentRunner.validate(ParentRunner.java:416)
    at org.junit.runners.ParentRunner.<init>(ParentRunner.java:84)
    at org.junit.runners.BlockJUnit4ClassRunner.<init>(BlockJUnit4ClassRunner.java:65)
    at org.junit.runners.parameterized.BlockJUnit4ClassRunnerWithParameters.<init>(BlockJUnit4ClassRunnerWithParameters.java:27)
    at org.junit.runners.parameterized.BlockJUnit4ClassRunnerWithParametersFactory.createRunnerForTestWithParameters(BlockJUnit4ClassRunnerWithParametersFactory.java:16)
    at org.junit.runners.Parameterized.createRunnersForParameters(Parameterized.java:313)
    at org.junit.runners.Parameterized.<init>(Parameterized.java:248)
    at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:490)
    at org.junit.internal.builders.AnnotatedBuilder.buildRunner(AnnotatedBuilder.java:104)
    at org.junit.vintage.engine.discovery.DefensiveAllDefaultPossibilitiesBuilder$DefensiveAnnotatedBuilder.buildRunner(DefensiveAllDefaultPossibilitiesBuilder.java:113)

这是我的代码的最新版本：

package assignments;

import edu.princeton.cs.algs4.In;
import org.junit.jupiter.api.Test;
import org.junit.runner.RunWith;
import org.junit.runners.Parameterized;

import java.io.File;
import java.util.ArrayList;

import static junit.framework.TestCase.assertEquals;

@RunWith(Parameterized.class)
public class SolverTest {
    final static File folder = new File("C:\Users\Azizam\IdeaProjects\EightPuzzle\src\ModifiedTests");
    final static String destFolder = "C:\Users\Azizam\IdeaProjects\EightPuzzle\src\testresults";
    final static ArrayList<Object[][]> filesList = new ArrayList<>();
    final Object currentBoard = new Object();

    @Parameterized.Parameters
    public static Iterable<Object[][]> data() {
        String path = "";
        int counter = 0;
        for (final File fileEntry : folder.listFiles()) {
            //System.out.println("processing file: " + fileEntry.getName())
            counter++;
            if (counter == 20) break;
            path = destFolder + fileEntry;
            In in = new In(fileEntry.getAbsolutePath());
            int n = in.readInt();
            int moves = in.readInt();
            int[][] tiles = new int[n][n];
            for (int i = 0; i < n; i++)
                for (int j = 0; j < n; j++)
                    tiles[i][j] = in.readInt();
            Board b = new Board(tiles);
            Object[][] fileList = new Object[][]{{b, moves}};
            filesList.add(fileList);
        }
        return filesList;
    }

    @Parameterized.Parameter(0)
    public Board board;
    @Parameterized.Parameter(1)
    public int expectedNumberOfMoves;

    public SolverTest() {
    }


    @Test
    public void test() {
        assertEquals(expectedNumberOfMoves, new Solver(board).moves());
    }

}

这是调试会话的图片，显示了文件列表中我想要的所有内容。一些板对象如何不转移到我的规划求解构造函数。

Answer 1

这里是无参数构造函数错误的意思。

测试class中的构造函数如下：

public SolverTest(Board board, int expectedNumberOfMoves) {
    this.board = board;
    this.expectedNumberOfMoves = expectedNumberOfMoves;
}

它有 2 个参数，因此不是无参数构造函数。下面是一个无参数的构造函数：

public SolverTest() {
}

删除 2-arg 构造函数将起作用，因此不需要显式列出，因为 java 编译器会自动添加默认的无参数构造函数。

然而错误的原因是 Parameterized 测试 class.

的 2 种方法的混合

要么使用带有 @Parameterized.Parameters 字段的无参数构造函数（顺便说一句，它需要是 public 而不是私有的），或者删除这些字段并使用带有参数的构造取参数

这是为使用第一种方法（即使用 @Parameterized.Parameters 字段）修改的代码：

@RunWith(Parameterized.class)
public class SolverTest {
    final static File folder = new File("C:\Users\Azizam\IdeaProjects\EightPuzzle\src\ModifiedTests");
    final static String destFolder = "C:\Users\Azizam\IdeaProjects\EightPuzzle\src\testresults";
    final static ArrayList<Object[][]> filesList = new ArrayList<>();
    final Object currentBoard = new Object();

    @Parameterized.Parameters
    public static Iterable<Object[][]> data() {
        String path = "";
        int counter = 0;
        for (final File fileEntry : folder.listFiles()) {
            //System.out.println("processing file: " + fileEntry.getName())
            counter++;
            if (counter == 20) break;
            path = destFolder + fileEntry;
            In in = new In(fileEntry.getAbsolutePath());
            int n = in.readInt();
            int moves = in.readInt();
            int[][] tiles = new int[n][n];
            for (int i = 0; i < n; i++)
                for (int j = 0; j < n; j++)
                    tiles[i][j] = in.readInt();
            Board b = new Board(tiles);
            Object[][] fileList = new Object[][]{{b, moves}};
            filesList.add(fileList);
        }
        return filesList;
    }

    @Parameterized.Parameter(0)
    public Board board;
    @Parameterized.Parameter(1)
    public int expectedNumberOfMoves;

    public SolverTest() {
    }


    @Test
    public void test() {
        assertEquals(expectedNumberOfMoves, new Solver(board).moves());
    }

}

junit java 错误消息的参数化测试构造函数：测试 class 应该只有一个 public 零参数构造函数

parameterized test constructor of junit java error message: Test class should have exactly one public zero-argument constructor

java

junit

unit-testing

intellij-idea

parameterized-unit-test