*/
    String getSource();

    /**
     * Gets the one-based index of the line containing the problem. The line number should refer to some text file that
     * is given by {@link #getSource()}.
     *
     * @return The one-based index of the line containing the problem or a non-positive value if unknown.
     */
    int getLineNumber();

    /**

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

Аналогично, вы можете объявлять необязательные query-параметры, установив их значение по умолчанию, равное `None`:

{* ../../docs_src/query_params/tutorial002_py310.py hl[7] *}

В этом случае, параметр  `q` будет не обязательным и будет иметь значение `None` по умолчанию.

/// check | Важно

}

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

	if hamsterToy.Name != hamster.PreferredToy.Name {
		t.Errorf("Should find has one polymorphic association")
	}

	hamsterToy = Toy{}
	DB.Model(&hamster).Association("OtherToy").Find(&hamsterToy)
	if hamsterToy.Name != hamster.OtherToy.Name {
		t.Errorf("Should find has one polymorphic association")
	}

	// Append
	DB.Model(&hamster).Association("PreferredToy").Append(&Toy{
		Name: "bike 2",

```
http://127.0.0.1:8000/items/?skip=20
```

查询参数的值就是：

* `skip=20`：在 URL 中设定的值
* `limit=10`：使用默认值

## 可选参数 { #optional-parameters }

同理，把默认值设为 `None` 即可声明可选的查询参数：

{* ../../docs_src/query_params/tutorial002_py310.py hl[7] *}

本例中，查询参数 `q` 是可选的，默认值为 `None`。

/// check | 检查

注意，**FastAPI** 可以识别出 `item_id` 是路径参数，`q` 不是路径参数，而是查询参数。

///

## 查询参数类型转换 { #query-parameter-type-conversion }

    assert response.status_code == 200
    assert response.json() == {
        "item_id": 5,
        "item": {"name": "Foo", "price": 3.0, "description": None, "tax": None},
    }


def test_items_6(client: TestClient):
    response = client.put(
        "/items/6",
        json={
            "item": {
                "name": "Bar",
                "price": 0.2,

    )
    assert response.status_code == 200
    assert response.json() == {
        "item_id": 123,
        "name": "Foo",
        "price": 50.1,
        "description": None,
        "tax": None,
    }


def test_put_with_no_data(client: TestClient):
    response = client.put("/items/123", json={})
    assert response.status_code == 422
    assert response.json() == {
        "detail": [

	},
	{ // 2. replication status for one target
		name:      "replication status for one target",
		rs:        ReplicationState{ReplicationStatusInternal: "arn1=PENDING;", Targets: map[string]replication.StatusType{"arn1": "PENDING"}},
		expStatus: replication.Pending,
	},
	{ // 3. replication status for one target - incorrect format
		name:      "replication status for one target",

  }

  public void testForMapWithoutDefault() {
    Map<String, @Nullable Integer> map = new HashMap<>();
    map.put("One", 1);
    map.put("Three", 3);
    map.put("Null", null);
    Function<String, @Nullable Integer> function = Functions.forMap(map);

    assertEquals(1, function.apply("One").intValue());
    assertEquals(3, function.apply("Three").intValue());
    assertThat(function.apply("Null")).isNull();