modernize-tests

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Modernize Tests

测试现代化

Test modernization refers to two potential actions: migrating from XCTest to Swift Testing, and updating existing Swift Testing tests to use recommended patterns.

XCTests should be migrated to Swift Testing when possible. However, not all XCTests can be migrated to Swift Testing.

UI tests (those that use XCUIAutomation) cannot be written with Swift Testing, and must remain XCTests.
XCTests that use the
```
measure { ... }
```
family of APIs for performance measurement cannot be migrated. However, other test methods within an XCTestCase that do not use XCTest performance APIs can be migrated.

测试现代化包含两种操作：从XCTest迁移至Swift Testing，以及更新现有Swift Testing测试以使用推荐的模式。

在可行的情况下，应将XCTest迁移至Swift Testing，但并非所有XCTest都能完成迁移：

UI测试（使用XCUIAutomation的测试）无法用Swift Testing编写，必须保留为XCTest。
使用
```
measure { ... }
```
系列API进行性能测量的XCTest无法迁移，但XCTestCase中不使用XCTest性能API的其他测试方法可以迁移。

Migration Reference

迁移参考

Imports

导入

Replace

import XCTest

with

import Testing

. A file can import both if it contains mixed test content during incremental migration.

When removing

import XCTest

, check whether the file uses Foundation types (URL, CharacterSet, ProcessInfo, Data, etc.). XCTest re-exports Foundation, so add

import Foundation

if needed.

将

import XCTest

替换为

import Testing

。在增量迁移期间，如果文件包含混合测试内容，可以同时导入两者。

移除

import XCTest

时，请检查文件是否使用Foundation类型（如URL、CharacterSet、ProcessInfo、Data等）。由于XCTest会重新导出Foundation，因此如果需要，请添加

import Foundation

。

Test Classes to Suites

测试类转测试套件

Remove

XCTestCase

inheritance. Prefer structs over classes:

final class FoodTruckTests: XCTestCase { ... }

struct FoodTruckTests { ... }

移除

XCTestCase

继承。优先使用结构体而非类：

final class FoodTruckTests: XCTestCase { ... }

struct FoodTruckTests { ... }

Move setUp/tearDown code to init/deinit

将setUp/tearDown代码迁移至init/deinit

Replace

override func setUp()

with

init()

(can be

async throws

). Replace

override func tearDown()

with

deinit

. If

deinit

is needed, use

actor

final class

instead of

struct

(since structs have no

deinit

). Change stored properties to not use implicitly-unwrapped optional types, and move their initial assignment from

setUp

to either be initialized inline or, if the initialization is complex, in an initializer.

struct MyTests {
    var fixture = Fixture()
    mutating func `Fixture behaves as expected`() {
        #expect(fixture.doSomething())
    }
}

Avoid pulling instance variables into function bodies; this can cause noise. Swift Testing reinvokes the initializer fresh before each test runs. If the test mutates an instance variable with value semantics, you may need to mark the test function

mutating

将

override func setUp()

替换为

init()

（可以是

async throws

）。将

override func tearDown()

替换为

deinit

。如果需要

deinit

，请使用

actor

或

final class

而非结构体（因为结构体没有

deinit

）。将存储属性改为不使用隐式解包可选类型，并将其初始赋值从

setUp

移至内联初始化，或者如果初始化逻辑复杂，则移至初始化器中。

struct MyTests {
    var fixture = Fixture()
    mutating func `Fixture behaves as expected`() {
        #expect(fixture.doSomething())
    }
}

避免将实例变量放入函数体内，这会产生冗余代码。Swift Testing会在每次测试运行前重新调用初始化器。如果测试使用值语义修改实例变量，可能需要将测试函数标记为

mutating

。

Test Methods

测试方法

Replace the

test

name prefix with the

@Test

attribute. If the resulting test name includes multiple camelCase words, use a raw identifier with the test name in sentence case.

func testEngineDoesNotStall() { ... }

@Test func

Engine does not stall

() { ... }

func testIgnition() { ... }

@Test func ignition() { ... }

Test functions can be

async

throws

, or

async throws

, and can be isolated to a global actor with

@MainActor

将

test

名称前缀替换为

@Test

属性。如果生成的测试名称包含多个驼峰式单词，请使用原始标识符并将测试名称改为句子格式。

func testEngineDoesNotStall() { ... }

@Test func

Engine does not stall

() { ... }

func testIgnition() { ... }

@Test func ignition() { ... }

测试函数可以是

async

、

throws

或

async throws

，也可以通过

@MainActor

隔离到全局actor。

Assertions to Expectations

断言转预期

When migrating a test from XCTest to Swift Testing, apply these mappings:

XCTAssert(x)

XCTAssertTrue(x)

#expect(x)

XCTAssertFalse(x)

#expect(!x)

XCTAssertNil(x)

#expect(x == nil)

XCTAssertNotNil(x)

#expect(x != nil)

XCTAssertEqual(x, y)

#expect(x == y)

XCTAssertNotEqual(x, y)

#expect(x != y)

XCTAssertIdentical(x, y)

#expect(x === y)

XCTAssertNotIdentical(x, y)

#expect(x !== y)

XCTAssertGreaterThan(x, y)

#expect(x > y)

XCTAssertGreaterThanOrEqual(x, y)

#expect(x >= y)

XCTAssertLessThanOrEqual(x, y)

#expect(x <= y)

XCTAssertLessThan(x, y)

#expect(x < y)

try XCTUnwrap(x)

try #require(x)

There is no direct equivalent for

XCTAssertEqual(_:_:accuracy:)

; use floating point math directly.

将测试从XCTest迁移至Swift Testing时，请应用以下映射：

XCTAssert(x)

、

XCTAssertTrue(x)

#expect(x)

XCTAssertFalse(x)

#expect(!x)

XCTAssertNil(x)

#expect(x == nil)

XCTAssertNotNil(x)

#expect(x != nil)

XCTAssertEqual(x, y)

#expect(x == y)

XCTAssertNotEqual(x, y)

#expect(x != y)

XCTAssertIdentical(x, y)

#expect(x === y)

XCTAssertNotIdentical(x, y)

#expect(x !== y)

XCTAssertGreaterThan(x, y)

#expect(x > y)

XCTAssertGreaterThanOrEqual(x, y)

#expect(x >= y)

XCTAssertLessThanOrEqual(x, y)

#expect(x <= y)

XCTAssertLessThan(x, y)

#expect(x < y)

try XCTUnwrap(x)

try #require(x)

XCTAssertEqual(_:_:accuracy:)

没有直接等效的API，请直接使用浮点数运算。

Errors

错误处理

When the error type is

Equatable

and the exact value is known, prefer to check the specific error value.

XCTAssertThrowsError(try f())

#expect(throws: (any Error).self) {
    try f()
}

XCTAssertThrowsError(try f()) { error in
    XCTAssertEqual(error, specificError)
}

#expect(throws: specificError) {
    try f()
}

XCTAssertThrowsError(try f()) { error in
    // Check error
}

let error = #expect(throws: (any Error).self) {
    try f()
}
// Check error

XCTAssertNoThrow(try f())

#expect(throws: Never.self) {
    try f()
}

当错误类型遵循

Equatable

且已知确切值时，优先检查特定错误值。

XCTAssertThrowsError(try f())

#expect(throws: (any Error).self) {
    try f()
}

XCTAssertThrowsError(try f()) { error in
    XCTAssertEqual(error, specificError)
}

#expect(throws: specificError) {
    try f()
}

XCTAssertThrowsError(try f()) { error in
    // Check error
}

let error = #expect(throws: (any Error).self) {
    try f()
}
// Check error

XCTAssertNoThrow(try f())

#expect(throws: Never.self) {
    try f()
}

continueAfterFailure

By default

continueAfterFailure

is true, which means expectations do not halt the test run. Some XCTestCases set

continueAfterFailure = false

, which means the

XCTAssert

family of functions will throw Objective-C exceptions that halt the test execution.

When a test method sets

continueAfterFailure = false

, all subsequent assertions need to be

try #require(x)

instead of

#expect(x)

to preserve this behavior. When adding

try #require(x)

, add

throws

to the affected methods.

When

continueAfterFailure = false

is set in

setUp

, the conversion to

try #require(x)

must apply to all assertions in all test methods in that class.

默认情况下

continueAfterFailure

为true，这意味着预期不会终止测试运行。有些XCTestCase会设置

continueAfterFailure = false

，这意味着

XCTAssert

系列函数会抛出Objective-C异常以终止测试执行。

当测试方法设置

continueAfterFailure = false

时，所有后续断言需要改为

try #require(x)

而非

#expect(x)

，以保留该行为。添加

try #require(x)

时，请为受影响的方法添加

throws

。

如果在

setUp

中设置了

continueAfterFailure = false

，则该类中所有测试方法的所有断言都必须转换为

try #require(x)

。

Promote

Issue.record

XCTFail

to expectations

将

Issue.record

XCTFail

升级为预期

Wherever it is not disruptive, convert usage of

Issue.record

XCTFail

to #expect or #require, depending if the test exits after (taking

continueAfterFailure

into account).

In some cases, the source of the expectation itself is sufficient to explain the failure, and the comment would be redundant.

For example, the following structures should be converted as such:

guard let object = somethingOptional() else {
    Issue.record("Could not get object")
    return
}

guard object.isAvailable() else {
    Issue.record("Object not available")
    return
}

if !object.performOperation() {
    Issue.record("Failed to perform operation")
}

let object = try #require(somethingOptional(), "Could not get object")
try #require(object.isAvailable())
#expect(object.performOperation())

在不影响逻辑的情况下，将

Issue.record

或

XCTFail

的用法转换为#expect或#require，具体取决于测试是否会在失败后退出（需考虑

continueAfterFailure

的设置）。

在某些情况下，预期本身的来源足以解释失败原因，此时注释会显得冗余。

例如，以下结构应按如下方式转换：

guard let object = somethingOptional() else {
    Issue.record("Could not get object")
    return
}

guard object.isAvailable() else {
    Issue.record("Object not available")
    return
}

if !object.performOperation() {
    Issue.record("Failed to perform operation")
}

let object = try #require(somethingOptional(), "Could not get object")
try #require(object.isAvailable())
#expect(object.performOperation())

Asynchronous Expectations to Confirmations

异步预期转确认

Replace

XCTestExpectation

fulfill()

await fulfillment(of:)

with

confirmation()

swift

// Before
let exp = expectation(description: "...")
handler = { exp.fulfill() }
doWork()
await fulfillment(of: [exp])

// After
await confirmation("...") { confirm in
    handler = { confirm() }
    doWork()
}

For

assertForOverFulfill = false

with an

expectedFulfillmentCount

, use a range:

await confirmation("...", expectedCount: 10...) { confirm in ... }

将

XCTestExpectation

fulfill()

await fulfillment(of:)

替换为

confirmation()

：

swift

// Before
let exp = expectation(description: "...")
handler = { exp.fulfill() }
doWork()
await fulfillment(of: [exp])

// After
await confirmation("...") { confirm in
    handler = { confirm() }
    doWork()
}

对于设置

assertForOverFulfill = false

且指定

expectedFulfillmentCount

的情况，请使用范围：

await confirmation("...", expectedCount: 10...) { confirm in ... }

Skipping Tests

跳过测试

Replace

XCTSkipIf

XCTSkipUnless

with traits on the test or suite:

try XCTSkipIf(condition)

@Test(.disabled(if: condition))

try XCTSkipUnless(condition)

@Test(.enabled(if: condition))

Replace

throw XCTSkip("reason")

mid-test with

try Test.cancel("reason")

When a skip checks OS version or platform availability, replace it with an

@available

attribute on the test function instead of

.enabled(if:)

将

XCTSkipIf

XCTSkipUnless

替换为测试或套件的特性：

try XCTSkipIf(condition)

@Test(.disabled(if: condition))

try XCTSkipUnless(condition)

@Test(.enabled(if: condition))

将测试中途的

throw XCTSkip("reason")

替换为

try Test.cancel("reason")

。

当跳过检查依赖于OS版本或平台可用性时，请将其替换为测试函数上的

@available

属性，而非

.enabled(if:)

。

Known Issues

已知问题

Replace

XCTExpectFailure("...", ...) { ... }

with

withKnownIssue("...") { ... }

For intermittent failures, replace

.nonStrict()

option (or the shorthand

strict: false

parameter) with

isIntermittent: true

For conditional/matching: use

when:

and

matching:

parameters:

swift

withKnownIssue("...") {
    try riskyOperation()
} when: {
    shouldExpectFailure
} matching: { issue in
    issue.error != nil
}

将

XCTExpectFailure("...", ...) { ... }

替换为

withKnownIssue("...") { ... }

。

对于间歇性失败，请将

.nonStrict()

选项（或简写的

strict: false

参数）替换为

isIntermittent: true

。

对于条件/匹配：使用

when:

和

matching:

参数：

swift

withKnownIssue("...") {
    try riskyOperation()
} when: {
    shouldExpectFailure
} matching: { issue in
    issue.error != nil
}

Concurrency and Serial Execution

并发与串行执行

XCTest runs synchronous tests on the main actor and sequentially within a suite by default. Swift Testing runs all test functions on an arbitrary task and in parallel. Add

@MainActor

only if a test explicitly relied on main-actor isolation in its XCTest form, and add

@Suite(.serialized)

if tests depend on shared state.

默认情况下，XCTest在主actor上运行同步测试，并在套件内按顺序执行。Swift Testing在任意任务上并行运行所有测试函数。仅当测试在XCTest形式下明确依赖主actor隔离时，才添加

@MainActor

；如果测试依赖共享状态，请添加

@Suite(.serialized)

。

Attachments

附件

Replace

XCTAttachment

self.add(attachment)

with

Attachment.record(value)

. The attached type must conform to

Attachable

(automatic for

Codable

and

NSSecureCoding

types when Foundation is imported).

将

XCTAttachment

self.add(attachment)

替换为

Attachment.record(value)

。附件类型必须遵循

Attachable

协议（导入Foundation时，

Codable

和

NSSecureCoding

类型会自动遵循该协议）。

Modernization Guidelines

现代化指南

When migrating from XCTest, migrate one test class at a time. A file can contain both XCTest and Swift Testing tests during migration.
Prefer
```
struct
```
for suites unless
```
deinit
```
(tearDown) is needed, in which case use
```
actor
```
or
```
final class
```
.
Remove the
```
test
```
prefix from method names when adding
```
@Test
```
. For lengthier test names which read like a sentence, use raw identifier syntax to improve readability, e.g.
```
@Test func 
```
Authenticate, fetch summary, then check count
```
() { ... }
```
.
Use raw identifier syntax only for multi-word names that read like a sentence.
When migrating
```
setUp
```
, convert implicitly-unwrapped optional properties to non-optional properties initialized in-place, or in
```
init
```
if initialization is complex, may throw, or is async.
Look for explicit
```
XCTFail
```
/
```
Issue.record
```
calls that could be converted to
```
#expect
```
or
```
#require
```
Do not change
```
try #require
```
calls into
```
#expect
```
; this changes the behavior of tests.
Add
```
@MainActor
```
only to tests that explicitly relied on XCTest's implicit main-actor isolation. Do not add it unnecessarily.
Look for tests that loop over inputs or many repeated tests with the same logic and convert them to parameterized tests using
```
@Test(arguments:)
```
.
For suites with shared mutable state between tests, add
```
@Suite(.serialized)
```
and consider using
```
actor
```
or
```
class
```
instead of
```
struct
```
.
Do not introduce usage of underscore-prefixed symbols such as
```
#_sourceLocation
```
; only use public API. For source locations, always use the full
```
SourceLocation(fileID:filePath:line:column:)
```
initializer.
If the test suite already uses #_sourceLocation, do not replace the existing usage as part of modernization.
Split this work over multiple agents if necessary if the modernization task is complex

从XCTest迁移时，一次迁移一个测试类。迁移期间，一个文件可以同时包含XCTest和Swift Testing测试。
优先为测试套件使用
```
struct
```
，除非需要
```
deinit
```
（即tearDown），此时请使用
```
actor
```
或
```
final class
```
。
添加
```
@Test
```
时，移除方法名称中的
```
test
```
前缀。对于较长且读起来像句子的测试名称，请使用原始标识符语法以提高可读性，例如
```
@Test func 
```
Authenticate, fetch summary, then check count
```
() { ... }
```
。
仅对读起来像句子的多词名称使用原始标识符语法。
迁移
```
setUp
```
时，将隐式解包可选属性转换为非可选属性，在内联中初始化，或者如果初始化逻辑复杂、可能抛出错误或为异步，则在
```
init
```
中初始化。
查找可转换为
```
#expect
```
或
```
#require
```
的显式
```
XCTFail
```
/
```
Issue.record
```
调用。
不要将
```
try #require
```
调用改为
```
#expect
```
，这会改变测试的行为。
仅对明确依赖XCTest隐式主actor隔离的测试添加
```
@MainActor
```
，不要不必要地添加。
查找循环处理输入或重复使用相同逻辑的测试，并使用
```
@Test(arguments:)
```
将其转换为参数化测试。
对于测试之间存在共享可变状态的套件，添加
```
@Suite(.serialized)
```
，并考虑使用
```
actor
```
或
```
class
```
而非
```
struct
```
。
不要使用以下划线开头的符号，例如
```
#_sourceLocation
```
；仅使用公开API。对于源位置，请始终使用完整的
```
SourceLocation(fileID:filePath:line:column:)
```
初始化器。
如果测试套件已在使用
```
#_sourceLocation
```
，则不要在现代化过程中替换现有用法。
如果现代化任务复杂，必要时可将工作分配给多个Agent完成

modernize-tests

Original

Translation

Modernize Tests

测试现代化

Migration Reference

迁移参考

Imports

导入

Test Classes to Suites

测试类转测试套件

Move setUp/tearDown code to init/deinit

将setUp/tearDown代码迁移至init/deinit

Test Methods

测试方法

Assertions to Expectations

断言转预期

Errors

错误处理

continueAfterFailure

continueAfterFailure

Promote
`Issue.record`
/
`XCTFail`
to expectations

将
`Issue.record`
/
`XCTFail`
升级为预期

Asynchronous Expectations to Confirmations

异步预期转确认

Skipping Tests

跳过测试

Known Issues

已知问题

Concurrency and Serial Execution

并发与串行执行

Attachments

附件

Modernization Guidelines

现代化指南

modernize-tests

Original

Translation

Modernize Tests

测试现代化

Migration Reference

迁移参考

Imports

导入

Test Classes to Suites

测试类转测试套件

Move setUp/tearDown code to init/deinit

将setUp/tearDown代码迁移至init/deinit

Test Methods

测试方法

Assertions to Expectations

断言转预期

Errors

错误处理

continueAfterFailure

continueAfterFailure

Promote Issue.record/XCTFail to expectations

将Issue.record/XCTFail升级为预期

Asynchronous Expectations to Confirmations

异步预期转确认

Skipping Tests

跳过测试

Known Issues

已知问题

Concurrency and Serial Execution

并发与串行执行

Attachments

附件

Modernization Guidelines

现代化指南

Promote
`Issue.record`
/
`XCTFail`
to expectations

将
`Issue.record`
/
`XCTFail`
升级为预期