# 请求体 - 嵌套模型 { #body-nested-models }

使用 **FastAPI**，你可以定义、校验、记录文档并使用任意深度嵌套的模型（归功于Pydantic）。

## List 字段 { #list-fields }

你可以将一个属性定义为一个子类型。例如，Python `list`：

{* ../../docs_src/body_nested_models/tutorial001_py310.py hl[12] *}

这将使 `tags` 成为一个由元素组成的列表。不过它没有声明每个元素的类型。

## 带类型参数的 List 字段 { #list-fields-with-type-parameter }

不过，Python 有一种用于声明具有内部类型（类型参数）的列表的特定方式：

### 声明带类型参数的 `list` { #declare-a-list-with-a-type-parameter }

    }

    @Nested
    @DisplayName("Modification Behavior")
    class ModificationBehaviorTests {

        @Test
        @DisplayName("should not save modifications to disk")
        void shouldNotSaveModificationsToDisk() {
            assertFalse(checkGoal.shouldSaveModifications(), "Check goal should not save modifications to disk");
        }
    }

    @Nested
    @DisplayName("Execution")

    }

    @Nested
    @DisplayName("Modification Behavior")
    class ModificationBehaviorTests {

        @Test
        @DisplayName("should save modifications to disk")
        void shouldSaveModificationsToDisk() {
            assertTrue(applyGoal.shouldSaveModifications(), "Apply goal should save modifications to disk");
        }
    }

    @Nested
    @DisplayName("Execution")

import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Nested;
import org.junit.jupiter.api.Test;
import org.mockito.Mockito;

import jcifs.smb.SmbPipeHandleInternal;

/**
 * Unit tests for a class that implements the {@link SmbPipeHandle} interface.
 * This test class uses a mock implementation to ensure any class adhering to the
 * SmbPipeHandle contract is tested for correctness.
 */
public class SmbPipeHandleTest {

### Tested { #tested }

* 100% <dfn title="The amount of code that is automatically tested">test coverage</dfn>.
* 100% <dfn title="Python type annotations, with this your editor and external tools can give you better support">type annotated</dfn> code base.

import java.lang.reflect.Field;
import java.util.Arrays;
import java.util.stream.Stream;

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.params.ParameterizedTest;
import org.junit.jupiter.params.provider.Arguments;
import org.junit.jupiter.params.provider.CsvSource;

When you run a packaging test, Gradle will set up the target VM and mount your
repository directory in the VM. Once this is done, a Gradle task will issue a
Vagrant command to run a *nested* Gradle task on the VM. This nested Gradle
runs the actual "destructive" test classes.

. Install Virtual Box and Vagrant.
+
. (Optional) Install https://github.com/fgrehm/vagrant-cachier[vagrant-cachier] to squeeze

 * public class Books {
 *   public static Book hardcover(String title) {...}
 *   public static Book paperback(String title) {...}
 * }
 * </pre>
 *
 * <p>And all the created {@code Book} instances can be tested with:
 *
 * <pre>
 * new ClassSanityTester()
 *     .forAllPublicStaticMethods(Books.class)
 *     .thatReturn(Book.class)
 *     .testEquals(); // or testNulls(), testSerializable() etc.
 * </pre>
 *

	}

	var find1 Value
	err := DB.Joins("Nested").Joins("Nested.Join").Preload("Nested.Preloads").First(&find1, value1.ID).Error
	if err != nil {
		t.Errorf("failed to find value, got err: %v", err)
	}
	AssertEqual(t, find1, value1)

	var find2 Value
	// Joins will automatically add Nested queries.
	err = DB.Joins("Nested.Join").Preload("Nested.Preloads").First(&find2, value2.ID).Error
	if err != nil {

     * OS family that can be tested for. {@value}
     */
    private static final String FAMILY_OS2 = "os/2";

    /**
     * OS family that can be tested for. {@value}
     */
    private static final String FAMILY_NETWARE = "netware";

    /**
     * OS family that can be tested for. {@value}
     */
    private static final String FAMILY_DOS = "dos";

    /**
     * OS family that can be tested for. {@value}
     */