import java.lang.reflect.Field;
import java.net.Socket;
import java.util.concurrent.atomic.AtomicLong;

import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.DisplayName;
import org.junit.jupiter.api.Nested;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.extension.ExtendWith;
import org.mockito.Mock;
import org.mockito.junit.jupiter.MockitoExtension;
import org.mockito.junit.jupiter.MockitoSettings;

 *
 * @author Ben Yu
 */

@NullUnmarked
public class PackageSanityTests extends AbstractPackageSanityTests {
  public PackageSanityTests() {
    publicApiOnly(); // Many package-private classes are tested through the public API.
    setDefault(DiscreteDomain.class, DiscreteDomain.integers());
  }

import java.util.Collection;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * Creates collections, containing sample elements, to be tested.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
@NullMarked
public interface TestCollectionGenerator<E extends @Nullable Object>

                "flags should be DCERPC_FIRST_FRAG | DCERPC_LAST_FRAG");
        // Verify that the super constructor was called with the correct handle.
        // This is implicitly tested by the object being created without error and
        // the fields set by the constructor being correct.
    }

        assertNotNull(exception.getCause().getStackTrace());
        assertTrue(exception.getCause().getStackTrace().length > 0);
    }

    @Test
    public void test_multiLevelCause() {
        // Test with nested exceptions
        Throwable rootCause = new IllegalStateException("Root problem");
        Throwable intermediateCause = new RuntimeException("Intermediate problem", rootCause);

import java.util.Collection;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * Creates collections, containing sample elements, to be tested.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
@NullMarked
public interface TestCollectionGenerator<E extends @Nullable Object>

        assertEquals(message, exception.getMessage());
        assertNull(exception.getCause());
    }

    @Test
    public void test_constructor_withNestedCause() {
        // Test constructor with nested exceptions
        Throwable rootCause = new IllegalStateException("Root cause");
        Throwable intermediateCause = new RuntimeException("Intermediate cause", rootCause);
        String message = "Top level error";

                            return
                        }
                        val outputPrefix = if (file.startsWith("/META-INF/versions")) {
                            // Java 9 multi-release JAR entry, we must keep it nested in the output
                            file.subpath(0, 3).toString()
                        } else {
                            ""
                        }

{* ../../docs_src/dataclasses_/tutorial002_py310.py hl[1,6:12,18] *}

该数据类会被自动转换为 Pydantic 的数据类。

这样，它的模式会显示在 API 文档界面中：

<img src="/img/tutorial/dataclasses/image01.png">

## 在嵌套数据结构中使用数据类 { #dataclasses-in-nested-data-structures }

你也可以把 `dataclasses` 与其它类型注解组合在一起，创建嵌套数据结构。

在某些情况下，你可能仍然需要使用 Pydantic 的 `dataclasses` 版本。例如，如果自动生成的 API 文档出现错误。

在这种情况下，你可以直接把标准的 `dataclasses` 替换为 `pydantic.dataclasses`，它是一个可直接替换的实现：

import com.google.common.annotations.GwtCompatible;
import java.util.Set;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * Creates sets, containing sample elements, to be tested.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
@NullMarked
public interface TestSetGenerator<E extends @Nullable Object> extends TestCollectionGenerator<E> {
  @Override
  Set<E> create(Object... elements);