Iterator<Subscriber> one = registry.getSubscribers("");
    assertEquals(s1, one.next().target);
    assertFalse(one.hasNext());

    one = registry.getSubscribers("");

    registry.register(s2);
    registry.register(o1);

    Iterator<Subscriber> three = registry.getSubscribers("");
    assertEquals(s1, one.next().target);
    assertFalse(one.hasNext());

}

func TestPolymorphicHasOneAssociationForSlice(t *testing.T) {
	pets := []Pet{
		{Name: "hasone-1", Toy: Toy{Name: "toy-has-one"}},
		{Name: "hasone-2", Toy: Toy{}},
		{Name: "hasone-3", Toy: Toy{Name: "toy-has-one"}},
	}

	DB.Create(&pets)

	// Count
	AssertAssociationCount(t, pets, "Toy", 2, "")

	// Find
	var toys []Toy

                    "loc": ["header", "x-token"],
                    "msg": "Field required",
                    "input": None,
                },
                {
                    "type": "missing",
                    "loc": ["header", "x-key"],
                    "msg": "Field required",
                    "input": None,
                },
            ]
        }
    ) | IsDict(
        # TODO: remove when deprecating Pydantic v1

    assertMultimapEquals(ImmutableListMultimap.of("one", 1), "one", 1);
    assertMultimapEquals(ImmutableListMultimap.of("one", 1, "two", 2), "one", 1, "two", 2);
    assertMultimapEquals(
        ImmutableListMultimap.of("one", 1, "two", 2, "three", 3), "one", 1, "two", 2, "three", 3);
    assertMultimapEquals(
        ImmutableListMultimap.of("one", 1, "two", 2, "three", 3, "four", 4),
        "one",
        1,
        "two",
        2,

		{xForwardedFor, "", ""},                                                       // None
		{xRealIP, "8.8.8.8", "8.8.8.8"},                                               // Single address
		{xRealIP, "[2001:db8:cafe::17]:4711", "[2001:db8:cafe::17]"},                  // IPv6 address
		{xRealIP, "", ""},                                                             // None
		{forwarded, `for="_gazonk"`, "_gazonk"},                                       // Hostname

  /** Test an empty collection. */
  ZERO(0),
  /** Test a one-element collection. */
  ONE(1),
  /** Test a three-element collection. */
  SEVERAL(3),
  /*
   * TODO: add VERY_LARGE, noting that we currently assume that the fourth
   * sample element is not in any collection
   */

  ANY(ZERO, ONE, SEVERAL);

  private final Set<Feature<? super Collection>> implied;

    assert response.status_code == 200, response.text
    assert response.json() == {
        "name": "Foo",
        "price": 42,
        "description": None,
        "tax": None,
        "tags": [],
    }


@needs_pydanticv2
def test_openapi_schema():
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text

    Iterator<Subscriber> one = registry.getSubscribers("");
    assertEquals(s1, one.next().target);
    assertFalse(one.hasNext());

    one = registry.getSubscribers("");

    registry.register(s2);
    registry.register(o1);

    Iterator<Subscriber> three = registry.getSubscribers("");
    assertEquals(s1, one.next().target);
    assertFalse(one.hasNext());

## 응답 모델 인코딩 매개변수

응답 모델은 아래와 같이 기본값을 가질 수 있습니다:

```Python hl_lines="11  13-14"
{!../../docs_src/response_model/tutorial004.py!}
```

* `description: Optional[str] = None`은 기본값으로 `None`을 갖습니다.
* `tax: float = 10.5`는 기본값으로 `10.5`를 갖습니다.
* `tags: List[str] = []` 빈 리스트의 기본값으로: `[]`.

그러나 실제로 저장되지 않았을 경우 결과에서 값을 생략하고 싶을 수 있습니다.

def get_client():
    app = FastAPI()
    with pytest.warns(DeprecationWarning):

        @app.get("/items/")
        async def read_items(
            q: Annotated[str | None, Query(regex="^fixedquery$")] = None,
        ):
            if q:
                return f"Hello {q}"
            else:
                return "Hello World"

    client = TestClient(app)
    return client


@needs_py310