for (long a : UNSIGNED_INTS) {
      for (long b : UNSIGNED_INTS) {
        int cmpAsLongs = Longs.compare(a, b);
        int cmpAsUInt = UnsignedInts.compare((int) a, (int) b);
        assertThat(Integer.signum(cmpAsUInt)).isEqualTo(Integer.signum(cmpAsLongs));
      }
    }
  }

  public void testMax_noArgs() {
    assertThrows(IllegalArgumentException.class, () -> max());
  }

  public void testMax() {

```

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：

```Python hl_lines="1  6-9"
{!../../docs_src/path_params/tutorial005.py!}

// The opening parenthesis has been absorbed.
func (in *Input) argsFor(macro *Macro) map[string][]Token {
	var args [][]Token
	// One macro argument per iteration. Collect them all and check counts afterwards.
	for argNum := 0; ; argNum++ {
		tokens, tok := in.collectArgument(macro)
		args = append(args, tokens)
		if tok == ')' {
			break
		}
	}
	// Zero-argument macros are tricky.

    @Override
    double roundToDoubleArbitrarily(BigDecimal bigDecimal) {
      return bigDecimal.doubleValue();
    }

    @Override
    int sign(BigDecimal bigDecimal) {
      return bigDecimal.signum();
    }

    @Override
    BigDecimal toX(double d, RoundingMode mode) {
      return new BigDecimal(d);
    }

    @Override
    BigDecimal minus(BigDecimal a, BigDecimal b) {
      return a.subtract(b);

@GwtCompatible(serializable = true, emulated = true)
@SuppressWarnings("serial") // we're overriding default serialization
@ElementTypesAreNonnullByDefault
final class ImmutableEnumMap<K extends Enum<K>, V> extends IteratorBasedImmutableMap<K, V> {
  static <K extends Enum<K>, V> ImmutableMap<K, V> asImmutable(EnumMap<K, V> map) {
    switch (map.size()) {
      case 0:
        return ImmutableMap.of();
      case 1:

  private Class<? extends Enum> enumType;

  private String[] sampleData;

  @BeforeExperiment
  void setUp() throws ClassNotFoundException {
    Preconditions.checkArgument(hitRate >= 0 && hitRate <= 1, "hitRate must be in the range [0,1]");

    enumType =
        Class.forName(EnumsBenchmark.class.getCanonicalName() + "$" + enumSize + "Enum")
            .asSubclass(Enum.class);

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.hash;


/**
 * An enum that contains all of the known hash functions.
 *
 * @author Kurt Alfred Kluever
 */
enum HashFunctionEnum {
  ADLER32(Hashing.adler32()),
  CRC32(Hashing.crc32()),
  GOOD_FAST_HASH_32(Hashing.goodFastHash(32)),
  GOOD_FAST_HASH_64(Hashing.goodFastHash(64)),

        byte x = VALUES[i];
        byte y = VALUES[j];
        // note: spec requires only that the sign is the same
        assertWithMessage(x + ", " + y)
            .that(Math.signum(UnsignedBytes.compare(x, y)))
            .isEqualTo(Math.signum(Integer.compare(i, j)));
      }
    }
  }

  public void testMax_noArgs() {
    assertThrows(IllegalArgumentException.class, () -> max());
  }

  }

  @IgnoreJRERequirement // see enclosing class (whose annotation Animal Sniffer ignores here...)
  private static final class EnumSetAccumulator<E extends Enum<E>> {
    @SuppressWarnings({"rawtypes", "unchecked"})
    static final Collector<Enum<?>, ?, ImmutableSet<? extends Enum<?>>> TO_IMMUTABLE_ENUM_SET =
        (Collector) toImmutableEnumSetGeneric();

    @CheckForNull private EnumSet<E> set;

    void add(E e) {

from collections import deque
from dataclasses import dataclass
from datetime import datetime, timezone
from decimal import Decimal
from enum import Enum
from pathlib import PurePath, PurePosixPath, PureWindowsPath
from typing import Optional

import pytest
from fastapi._compat import PYDANTIC_V2, Undefined
from fastapi.encoders import jsonable_encoder
from pydantic import BaseModel, Field, ValidationError