BTrue:  true,
		I:      266703,
		INeg:   -266703,
		I8:     112,
		I8Neg:  -112,
		I16:    6703,
		I16Neg: -6703,
		I32:    266703,
		I32Neg: -266703,
		I64:    266703,
		I64Neg: -266703,
		UI:     266703,
		UI8:    112,
		UI16:   6703,
		UI32:   266703,
		UI64:   266703,
		F32:    266.703,
		F32Neg: -266.703,
		F64:    266.703,
		F64Neg: -266.703,
	}
	if v != want {

Jes Cok <******@****.***> 1712845527 +0800

Jes Cok <******@****.***> 1712845527 +0800

// Copyright 2018 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

//go:build cgo

// Issue 26743: typedef of uint leads to inconsistent typedefs error.
// No runtime test; just make sure it compiles.

package cgotest

package poll

import (
	"errors"
	"internal/syscall/unix"
	"syscall"
)

// Fsync invokes SYS_FCNTL with SYS_FULLFSYNC because
// on OS X, SYS_FSYNC doesn't fully flush contents to disk.
// See Issue #26650 as well as the man page for fsync on OS X.
func (fd *FD) Fsync() error {
	if err := fd.incref(); err != nil {
		return err
	}
	defer fd.decref()
	return ignoringEINTR(func() error {

type dnsNameTest struct {
	name   string
	result bool
}

var dnsNameTests = []dnsNameTest{
	// RFC 2181, section 11.
	{"_xmpp-server._tcp.google.com", true},
	{"foo.com", true},
	{"1foo.com", true},
	{"26.0.0.73.com", true},
	{"10-0-0-1", true},
	{"fo-o.com", true},
	{"fo1o.com", true},
	{"foo1.com", true},
	{"a.b..com", false},
	{"a.b-.com", false},
	{"a.b.com-", false},
	{"a.b..", false},
	{"b.com.", true},
}

And then **FastAPI** will call that override instead of the original dependency.

=== "Python 3.10+"

    ```Python hl_lines="26-27  30"
    {!> ../../../docs_src/dependency_testing/tutorial001_an_py310.py!}
    ```

=== "Python 3.9+"

    ```Python hl_lines="28-29  32"
    {!> ../../../docs_src/dependency_testing/tutorial001_an_py39.py!}
    ```

	{[]byte{255, 255, 255, 127}, true, "2.268435375", []uint64{2, 268435375}},
	{[]byte{0x87, 255, 255, 255, 127}, true, "2.2147483567", []uint64{2, 2147483567}},
	{[]byte{255, 127}, true, "2.16303", []uint64{2, 16303}},
	{[]byte{255, 255, 255, 255, 127}, true, "2.34359738287", []uint64{2, 34359738287}},
	{[]byte{255, 255, 255, 255, 255, 255, 255, 255, 127}, true, "2.9223372036854775727", []uint64{2, 9223372036854775727}},

Und dann ruft **FastAPI** diese Überschreibung anstelle der ursprünglichen Abhängigkeit auf.

=== "Python 3.10+"

    ```Python hl_lines="26-27  30"
    {!> ../../../docs_src/dependency_testing/tutorial001_an_py310.py!}
    ```

=== "Python 3.9+"

    ```Python hl_lines="28-29  32"
    {!> ../../../docs_src/dependency_testing/tutorial001_an_py39.py!}
    ```

### 使用 `app.dependency_overrides` 属性

对于这些用例，**FastAPI** 应用支持 `app.dependcy_overrides` 属性，该属性就是**字典**。

要在测试时覆盖原有依赖项，这个字典的键应当是原依赖项（函数），值是覆盖依赖项（另一个函数）。

这样一来，**FastAPI** 就会调用覆盖依赖项，不再调用原依赖项。

```Python hl_lines="26-27  30"
{!../../../docs_src/dependency_testing/tutorial001.py!}
```

!!! tip "提示"

    **FastAPI** 应用中的任何位置都可以实现覆盖依赖项。

    原依赖项可用于*路径操作函数*、*路径操作装饰器*（不需要返回值时）、`.include_router()` 调用等。

    FastAPI 可以覆盖这些位置的依赖项。