return Result.OK;
            } finally {
                reader.dispose();
            }
        }
        return Result.FAILED;
    }

    /**
     * Enumeration representing the possible results of thumbnail image processing.
     */
    protected enum Result {
        /** Thumbnail was successfully generated */
        OK,

        // Step 4: Initially no cached listing
        assertNull(directoryLeaseManager.getCachedDirectoryListing(directoryPath));

        // Step 5: Simulate directory enumeration and update cache
        List<SmbFile> files = Arrays.asList(mockFile1, mockFile2);
        directoryLeaseManager.updateDirectoryCache(directoryPath, files);

        // Step 6: Verify cache is complete and populated

                        "Expected invalid list operation message, was: " + ex.getMessage());
            }
        }
    }

    @Nested
    @DisplayName("Master browser enumeration tests")
    class MasterBrowserEnumerationTests {

        @Test
        @DisplayName("doEnum with empty host throws SmbUnsupportedOperationException when master browser not found")

    }

    @Test
    @DisplayName("Test nextElement method")
    void testNextElement() {
        // Test the nextElement method from Enumeration interface
        SmbComTransactionResponse element = response.nextElement();

        // Should return itself
        assertSame(response, element);

        // Can be called multiple times

                        set.add(e);
                    }
                }
            } catch (final IOException ioe) {
                log.debug("DS enumeration failed", ioe);
            }
        }

        final SmbTreeConnection treeConn = SmbTreeConnection.create(tc);
        try (SmbTreeHandleImpl th = treeConn.connectHost(locator, locator.getServerWithDfs());

  @GwtIncompatible // Maps.fromProperties
  public void testFromPropertiesNullKey() {
    Properties properties =
        new Properties() {
          @Override
          public Enumeration<?> propertyNames() {
            return Iterators.asEnumeration(asList(null, "first", "second").iterator());
          }
        };
    properties.setProperty("first", "true");
    properties.setProperty("second", "null");

        // Act: constructing the iterator must not throw and results in empty iterator
        DirFileEntryEnumIterator2 it = new DirFileEntryEnumIterator2(tree, parent, "*", null, 0);

        // Assert: enumeration is empty and close produced no extra close call (no fileId opened)
        assertFalse(it.hasNext(), "Empty listing should produce no elements");
        it.close();

{* ../../docs_src/path_params/tutorial003.py hl[6,11] *}

否则，`/users/{user_id}` 将匹配 `/users/me`，FastAPI 会**认为**正在接收值为 `"me"` 的 `user_id` 参数。

## 预设值

路径操作使用 Python 的 <abbr title="Enumeration">`Enum`</abbr> 类型接收预设的*路径参数*。

### 创建 `Enum` 类

导入 `Enum` 并创建继承自 `str` 和 `Enum` 的子类。

通过从 `str` 继承，API 文档就能把值的类型定义为**字符串**，并且能正确渲染。

然后，创建包含固定值的类属性，这些固定值是可用的有效值：

* Das Kommandozeileninterface

* der Server
* der Client

* der Cloudanbieter
* der Clouddienst

* die Entwicklung
* die Entwicklungsphasen

* das Dict
* das Dictionary
* die Enumeration
* das Enum
* das Enum-Member

* der Encoder
* der Decoder
* kodieren
* dekodieren

* die Exception
* werfen

* der Ausdruck
* die Anweisung

* das Frontend

    }
    
    private void discoverLocalInterfaces() {
        localInterfaces.clear();
        
        try {
            Enumeration<NetworkInterface> interfaces = NetworkInterface.getNetworkInterfaces();
            
            while (interfaces.hasMoreElements()) {
                NetworkInterface ni = interfaces.nextElement();