#### Define a *path operation decorator* { #define-a-path-operation-decorator }

{* ../../docs_src/first_steps/tutorial001_py310.py hl[6] *}

The `@app.get("/")` tells **FastAPI** that the function right below is in charge of handling requests that go to:

* the path `/`
* using a <dfn title="an HTTP GET method"><code>get</code> operation</dfn>

/// info | `@decorator` Info

That `@something` syntax in Python is called a "decorator".

### バックグラウンドタスクと `yield` を伴う依存関係、技術詳細 { #background-tasks-and-dependencies-with-yield-technical-details }

FastAPI 0.106.0 より前では、`yield` の後で例外を送出することはできませんでした。`yield` を持つ依存関係の終了コードはレスポンス送信「後」に実行されるため、[例外ハンドラ](../tutorial/handling-errors.md#install-custom-exception-handlers)はすでに実行済みでした。

これは主に、依存関係が "yield" した同じオブジェクトをバックグラウンドタスク内で利用できるようにするための設計でした。終了コードはバックグラウンドタスク完了後に実行されるからです。

            if (e.getCause().getMessage() != null) {
                assertTrue(e.getCause().getMessage().contains("Process start failed"));
            }
        }
    }

    // Test execute with exception handling
    @Test
    public void test_execute_withException() {
        pythonJob.filename("test.py");

        testProcessHelper.throwException = new RuntimeException("Unexpected error");

        assertEquals("groupList should remain empty", 0, groupList.size());
        assertEquals("roleList should remain empty", 0, roleList.size());
    }

    /**
     * Test addGroupOrRoleName with null value handling.
     */
    @Test
    public void test_addGroupOrRoleName_withEmptyValue() {
        EntraIdAuthenticator authenticator = new EntraIdAuthenticator();
        List<String> list = new ArrayList<>();

            // When & Then
            assertThrows(CIFSException.class, () -> transportPool.getChallenge(context, address));
        }
    }

    @Nested
    @DisplayName("Edge Cases and Error Handling")
    class EdgeCasesTests {

        @Test
        @DisplayName("Should handle null context")
        void testNullContext() {
            // Given

import java.util.concurrent.ForkJoinPool;

import javax.net.ssl.SSLSocketFactory;

import org.codelibs.curl.Curl.Method;
import org.junit.Test;

/**
 * Test class for CurlRequest.
 * Tests the fluent API, parameter handling, and request configuration.
 */
public class CurlRequestTest {

    @Test
    public void testConstructor() {
        String url = "https://example.com";

import jakarta.servlet.ServletContext;
import jakarta.servlet.SessionTrackingMode;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpSession;

/**
 * Helper class for handling view-related operations in the Fess search system.
 * This class provides utilities for content rendering, URL processing, highlighting,
 * caching, pagination, and user interface functionality.
 *
 */

 * This class contains various helper methods for formatting, parsing, and manipulating data
 * in Fess web templates, including date formatting, localization, file operations, and
 * query parameter handling.
 *
 * @since 1.0
 */
public class FessFunctions {
    /** Logger instance for this class */
    private static final Logger logger = LogManager.getLogger(FessFunctions.class);

        tagDifferentAttrValue.setCss("highlight");
        tagDifferentAttrValue.setAttr("data-value", "456");
        assertFalse(tag1.equals(tagDifferentAttrValue));

        // Null values handling
        PrunedTag tagWithNulls = new PrunedTag("div");
        PrunedTag anotherTagWithNulls = new PrunedTag("div");
        assertTrue(tagWithNulls.equals(anotherTagWithNulls));
    }

    @Test

 *
 * <p>Key features:</p>
 * <ul>
 *   <li>Concurrent crawler process management with configurable limits</li>
 *   <li>Selective crawling based on configuration IDs</li>
 *   <li>Document expiration handling</li>
 *   <li>Hot thread monitoring for performance analysis</li>
 *   <li>Process isolation with separate JVM</li>
 * </ul>
 */
public class CrawlJob extends ExecJob {