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測試

測試可協助您撰寫和維護程式碼,並防止迴歸。測試框架可協助您做到這一點,讓您可以描述程式碼應如何運作的斷言或期望。Svelte 對您使用的測試框架沒有既定看法 — 您可以使用 VitestJasmineCypressPlaywright 等解決方案來撰寫單元測試、整合測試和端對端測試。

使用 Vitest 進行單元和整合測試

單元測試可讓您測試程式碼的小型獨立部分。整合測試可讓您測試應用程式的各個部分,以查看它們是否協同運作。如果您正在使用 Vite(包括透過 SvelteKit),我們建議您使用 Vitest

若要開始使用,請安裝 Vitest

npm install -D vitest

然後調整您的 vite.config.js

vite.config
import { function defineConfig(config: UserConfig): UserConfig (+3 overloads)defineConfig } from 'vitest/config';

export default function defineConfig(config: UserConfig): UserConfig (+3 overloads)defineConfig({
	// ...
	// Tell Vitest to use the `browser` entry points in `package.json` files, even though it's running in Node
	
UserConfig.resolve?: (ResolveOptions & {
    alias?: AliasOptions;
}) | undefined

Configure resolver

resolve
: var process: NodeJS.Processprocess.NodeJS.Process.env: NodeJS.ProcessEnv

The process.env property returns an object containing the user environment. See environ(7).

An example of this object looks like:

{
  TERM: 'xterm-256color',
  SHELL: '/usr/local/bin/bash',
  USER: 'maciej',
  PATH: '~/.bin/:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin',
  PWD: '/Users/maciej',
  EDITOR: 'vim',
  SHLVL: '1',
  HOME: '/Users/maciej',
  LOGNAME: 'maciej',
  _: '/usr/local/bin/node'
}

It is possible to modify this object, but such modifications will not be reflected outside the Node.js process, or (unless explicitly requested) to other Worker threads. In other words, the following example would not work:

node -e 'process.env.foo = "bar"' && echo $foo

While the following will:

import { env } from 'node:process';

env.foo = 'bar';
console.log(env.foo);

Assigning a property on process.env will implicitly convert the value to a string. This behavior is deprecated. Future versions of Node.js may throw an error when the value is not a string, number, or boolean.

import { env } from 'node:process';

env.test = null;
console.log(env.test);
// => 'null'
env.test = undefined;
console.log(env.test);
// => 'undefined'

Use delete to delete a property from process.env.

import { env } from 'node:process';

env.TEST = 1;
delete env.TEST;
console.log(env.TEST);
// => undefined

On Windows operating systems, environment variables are case-insensitive.

import { env } from 'node:process';

env.TEST = 1;
console.log(env.test);
// => 1

Unless explicitly specified when creating a Worker instance, each Worker thread has its own copy of process.env, based on its parent thread’s process.env, or whatever was specified as the env option to the Worker constructor. Changes to process.env will not be visible across Worker threads, and only the main thread can make changes that are visible to the operating system or to native add-ons. On Windows, a copy of process.env on a Worker instance operates in a case-sensitive manner unlike the main thread.

@sincev0.1.27
env
.string | undefinedVITEST
? { ResolveOptions.conditions?: string[] | undefinedconditions: ['browser'] } : var undefinedundefined });

如果載入所有套件的瀏覽器版本是不希望的,因為(例如)您也測試後端程式庫,您可能需要採取別名組態

您現在可以為 .js/.ts 檔案中的程式碼撰寫單元測試

multiplier.svelte.test
import { function flushSync(fn?: (() => void) | undefined): void

Synchronously flushes any pending state changes and those that result from it.

flushSync
} from 'svelte';
import { const expect: ExpectStaticexpect, const test: TestAPI

Defines a test case with a given name and test function. The test function can optionally be configured with test options.

@paramname - The name of the test or a function that will be used as a test name.
@paramoptionsOrFn - Optional. The test options or the test function if no explicit name is provided.
@paramoptionsOrTest - Optional. The test function or options, depending on the previous parameters.
@throwsError If called inside another test function.
@examplets // Define a simple test test('should add two numbers', () => { expect(add(1, 2)).toBe(3); });
@examplets // Define a test with options test('should subtract two numbers', { retry: 3 }, () => { expect(subtract(5, 2)).toBe(3); });
test
} from 'vitest';
import { import multipliermultiplier } from './multiplier.js'; test<object>(name: string | Function, fn?: TestFunction<object> | undefined, options?: number | TestOptions): void (+2 overloads)

Defines a test case with a given name and test function. The test function can optionally be configured with test options.

@paramname - The name of the test or a function that will be used as a test name.
@paramoptionsOrFn - Optional. The test options or the test function if no explicit name is provided.
@paramoptionsOrTest - Optional. The test function or options, depending on the previous parameters.
@throwsError If called inside another test function.
@examplets // Define a simple test test('should add two numbers', () => { expect(add(1, 2)).toBe(3); });
@examplets // Define a test with options test('should subtract two numbers', { retry: 3 }, () => { expect(subtract(5, 2)).toBe(3); });
test
('Multiplier', () => {
let let double: anydouble = import multipliermultiplier(0, 2); expect<any>(actual: any, message?: string): Assertion<any> (+1 overload)expect(let double: anydouble.value).JestAssertion<any>.toEqual: <number>(expected: number) => voidtoEqual(0); let double: anydouble.set(5); expect<any>(actual: any, message?: string): Assertion<any> (+1 overload)expect(let double: anydouble.value).JestAssertion<any>.toEqual: <number>(expected: number) => voidtoEqual(10); });

在您的測試檔案中使用符文

可以在您的測試檔案中使用符文。首先,請確保您的綁定器知道在執行測試之前將檔案路由到 Svelte 編譯器,方法是將 .svelte 新增至檔名(例如 multiplier.svelte.test.js)。之後,您可以在測試中使用符文。

multiplier.svelte.test
import { function flushSync(fn?: (() => void) | undefined): void

Synchronously flushes any pending state changes and those that result from it.

flushSync
} from 'svelte';
import { const expect: ExpectStaticexpect, const test: TestAPI

Defines a test case with a given name and test function. The test function can optionally be configured with test options.

@paramname - The name of the test or a function that will be used as a test name.
@paramoptionsOrFn - Optional. The test options or the test function if no explicit name is provided.
@paramoptionsOrTest - Optional. The test function or options, depending on the previous parameters.
@throwsError If called inside another test function.
@examplets // Define a simple test test('should add two numbers', () => { expect(add(1, 2)).toBe(3); });
@examplets // Define a test with options test('should subtract two numbers', { retry: 3 }, () => { expect(subtract(5, 2)).toBe(3); });
test
} from 'vitest';
import { import multipliermultiplier } from './multiplier.svelte.js'; test<object>(name: string | Function, fn?: TestFunction<object> | undefined, options?: number | TestOptions): void (+2 overloads)

Defines a test case with a given name and test function. The test function can optionally be configured with test options.

@paramname - The name of the test or a function that will be used as a test name.
@paramoptionsOrFn - Optional. The test options or the test function if no explicit name is provided.
@paramoptionsOrTest - Optional. The test function or options, depending on the previous parameters.
@throwsError If called inside another test function.
@examplets // Define a simple test test('should add two numbers', () => { expect(add(1, 2)).toBe(3); });
@examplets // Define a test with options test('should subtract two numbers', { retry: 3 }, () => { expect(subtract(5, 2)).toBe(3); });
test
('Multiplier', () => {
let let count: numbercount =
function $state<0>(initial: 0): 0 (+1 overload)
namespace $state

Declares reactive state.

Example:

let count = $state(0);

https://svelte.dev.org.tw/docs/svelte/$state

@paraminitial The initial value
$state
(0);
let let double: anydouble = import multipliermultiplier(() => let count: numbercount, 2); expect<any>(actual: any, message?: string): Assertion<any> (+1 overload)expect(let double: anydouble.value).JestAssertion<any>.toEqual: <number>(expected: number) => voidtoEqual(0); let count: numbercount = 5; expect<any>(actual: any, message?: string): Assertion<any> (+1 overload)expect(let double: anydouble.value).JestAssertion<any>.toEqual: <number>(expected: number) => voidtoEqual(10); });

如果正在測試的程式碼使用效果,您需要將測試包裝在 $effect.root

logger.svelte.test
import { function flushSync(fn?: (() => void) | undefined): void

Synchronously flushes any pending state changes and those that result from it.

flushSync
} from 'svelte';
import { const expect: ExpectStaticexpect, const test: TestAPI

Defines a test case with a given name and test function. The test function can optionally be configured with test options.

@paramname - The name of the test or a function that will be used as a test name.
@paramoptionsOrFn - Optional. The test options or the test function if no explicit name is provided.
@paramoptionsOrTest - Optional. The test function or options, depending on the previous parameters.
@throwsError If called inside another test function.
@examplets // Define a simple test test('should add two numbers', () => { expect(add(1, 2)).toBe(3); });
@examplets // Define a test with options test('should subtract two numbers', { retry: 3 }, () => { expect(subtract(5, 2)).toBe(3); });
test
} from 'vitest';
import { import loggerlogger } from './logger.svelte.js'; test<object>(name: string | Function, fn?: TestFunction<object> | undefined, options?: number | TestOptions): void (+2 overloads)

Defines a test case with a given name and test function. The test function can optionally be configured with test options.

@paramname - The name of the test or a function that will be used as a test name.
@paramoptionsOrFn - Optional. The test options or the test function if no explicit name is provided.
@paramoptionsOrTest - Optional. The test function or options, depending on the previous parameters.
@throwsError If called inside another test function.
@examplets // Define a simple test test('should add two numbers', () => { expect(add(1, 2)).toBe(3); });
@examplets // Define a test with options test('should subtract two numbers', { retry: 3 }, () => { expect(subtract(5, 2)).toBe(3); });
test
('Effect', () => {
const const cleanup: () => voidcleanup =
namespace $effect
function $effect(fn: () => void | (() => void)): void

Runs code when a component is mounted to the DOM, and then whenever its dependencies change, i.e. $state or $derived values. The timing of the execution is after the DOM has been updated.

Example:

$effect(() => console.log('The count is now ' + count));

If you return a function from the effect, it will be called right before the effect is run again, or when the component is unmounted.

Does not run during server side rendering.

https://svelte.dev.org.tw/docs/svelte/$effect

@paramfn The function to execute
$effect
.function $effect.root(fn: () => void | (() => void)): () => void

The $effect.root rune is an advanced feature that creates a non-tracked scope that doesn’t auto-cleanup. This is useful for nested effects that you want to manually control. This rune also allows for creation of effects outside of the component initialisation phase.

Example:

&#x3C;script>
  let count = $state(0);

  const cleanup = $effect.root(() => {
	$effect(() => {
			console.log(count);
		})

	 return () => {
	   console.log('effect root cleanup');
			}
  });
&#x3C;/script>

&#x3C;button onclick={() => cleanup()}>cleanup&#x3C;/button>

https://svelte.dev.org.tw/docs/svelte/$effect#$effect.root

root
(() => {
let let count: numbercount =
function $state<0>(initial: 0): 0 (+1 overload)
namespace $state

Declares reactive state.

Example:

let count = $state(0);

https://svelte.dev.org.tw/docs/svelte/$state

@paraminitial The initial value
$state
(0);
// logger uses an $effect to log updates of its input let let log: anylog = import loggerlogger(() => let count: numbercount); // effects normally run after a microtask, // use flushSync to execute all pending effects synchronously function flushSync(fn?: (() => void) | undefined): void

Synchronously flushes any pending state changes and those that result from it.

flushSync
();
expect<any>(actual: any, message?: string): Assertion<any> (+1 overload)expect(let log: anylog.value).JestAssertion<any>.toEqual: <number[]>(expected: number[]) => voidtoEqual([0]); let count: numbercount = 1; function flushSync(fn?: (() => void) | undefined): void

Synchronously flushes any pending state changes and those that result from it.

flushSync
();
expect<any>(actual: any, message?: string): Assertion<any> (+1 overload)expect(let log: anylog.value).JestAssertion<any>.toEqual: <number[]>(expected: number[]) => voidtoEqual([0, 1]); }); const cleanup: () => voidcleanup(); });

組件測試

可以使用 Vitest 隔離測試您的組件。

在撰寫組件測試之前,請考慮您是否真的需要測試組件,或者它是否更關乎組件內部的邏輯。如果是這樣,請考慮提取該邏輯以進行隔離測試,而無需組件的開銷

若要開始使用,請安裝 jsdom(一個修補 DOM API 的程式庫)

npm install -D jsdom

然後調整您的 vite.config.js

vite.config
import { function defineConfig(config: UserConfig): UserConfig (+3 overloads)defineConfig } from 'vitest/config';

export default function defineConfig(config: UserConfig): UserConfig (+3 overloads)defineConfig({
	UserConfig.plugins?: PluginOption[] | undefined

Array of vite plugins to use.

plugins
: [
/* ... */ ], UserConfig.test?: InlineConfig | undefined

Options for Vitest

test
: {
// If you are testing components client-side, you need to setup a DOM environment. // If not all your files should have this environment, you can use a // `// @vitest-environment jsdom` comment at the top of the test files instead. InlineConfig.environment?: VitestEnvironment | undefined

Running environment

Supports ‘node’, ‘jsdom’, ‘happy-dom’, ‘edge-runtime’

If used unsupported string, will try to load the package vitest-environment-${env}

@default'node'
environment
: 'jsdom'
}, // Tell Vitest to use the `browser` entry points in `package.json` files, even though it's running in Node
UserConfig.resolve?: (ResolveOptions & {
    alias?: AliasOptions;
}) | undefined

Configure resolver

resolve
: var process: NodeJS.Processprocess.NodeJS.Process.env: NodeJS.ProcessEnv

The process.env property returns an object containing the user environment. See environ(7).

An example of this object looks like:

{
  TERM: 'xterm-256color',
  SHELL: '/usr/local/bin/bash',
  USER: 'maciej',
  PATH: '~/.bin/:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin',
  PWD: '/Users/maciej',
  EDITOR: 'vim',
  SHLVL: '1',
  HOME: '/Users/maciej',
  LOGNAME: 'maciej',
  _: '/usr/local/bin/node'
}

It is possible to modify this object, but such modifications will not be reflected outside the Node.js process, or (unless explicitly requested) to other Worker threads. In other words, the following example would not work:

node -e 'process.env.foo = "bar"' &#x26;#x26;&#x26;#x26; echo $foo

While the following will:

import { env } from 'node:process';

env.foo = 'bar';
console.log(env.foo);

Assigning a property on process.env will implicitly convert the value to a string. This behavior is deprecated. Future versions of Node.js may throw an error when the value is not a string, number, or boolean.

import { env } from 'node:process';

env.test = null;
console.log(env.test);
// => 'null'
env.test = undefined;
console.log(env.test);
// => 'undefined'

Use delete to delete a property from process.env.

import { env } from 'node:process';

env.TEST = 1;
delete env.TEST;
console.log(env.TEST);
// => undefined

On Windows operating systems, environment variables are case-insensitive.

import { env } from 'node:process';

env.TEST = 1;
console.log(env.test);
// => 1

Unless explicitly specified when creating a Worker instance, each Worker thread has its own copy of process.env, based on its parent thread’s process.env, or whatever was specified as the env option to the Worker constructor. Changes to process.env will not be visible across Worker threads, and only the main thread can make changes that are visible to the operating system or to native add-ons. On Windows, a copy of process.env on a Worker instance operates in a case-sensitive manner unlike the main thread.

@sincev0.1.27
env
.string | undefinedVITEST
? { ResolveOptions.conditions?: string[] | undefinedconditions: ['browser'] } : var undefinedundefined });

之後,您可以建立一個測試檔案,其中匯入要測試的組件,以程式方式與其互動,並撰寫有關結果的預期

component.test
import { function flushSync(fn?: (() => void) | undefined): void

Synchronously flushes any pending state changes and those that result from it.

flushSync
, function mount<Props extends Record<string, any>, Exports extends Record<string, any>>(component: ComponentType<SvelteComponent<Props>> | Component<Props, Exports, any>, options: MountOptions<Props>): Exports

Mounts a component to the given target and returns the exports and potentially the props (if compiled with accessors: true) of the component. Transitions will play during the initial render unless the intro option is set to false.

mount
, function unmount(component: Record<string, any>): void

Unmounts a component that was previously mounted using mount or hydrate.

unmount
} from 'svelte';
import { const expect: ExpectStaticexpect, const test: TestAPI

Defines a test case with a given name and test function. The test function can optionally be configured with test options.

@paramname - The name of the test or a function that will be used as a test name.
@paramoptionsOrFn - Optional. The test options or the test function if no explicit name is provided.
@paramoptionsOrTest - Optional. The test function or options, depending on the previous parameters.
@throwsError If called inside another test function.
@examplets // Define a simple test test('should add two numbers', () => { expect(add(1, 2)).toBe(3); });
@examplets // Define a test with options test('should subtract two numbers', { retry: 3 }, () => { expect(subtract(5, 2)).toBe(3); });
test
} from 'vitest';
import
type Component = SvelteComponent<Record<string, any>, any, any>
const Component: LegacyComponentType
Component
from './Component.svelte';
test<object>(name: string | Function, fn?: TestFunction<object> | undefined, options?: number | TestOptions): void (+2 overloads)

Defines a test case with a given name and test function. The test function can optionally be configured with test options.

@paramname - The name of the test or a function that will be used as a test name.
@paramoptionsOrFn - Optional. The test options or the test function if no explicit name is provided.
@paramoptionsOrTest - Optional. The test function or options, depending on the previous parameters.
@throwsError If called inside another test function.
@examplets // Define a simple test test('should add two numbers', () => { expect(add(1, 2)).toBe(3); });
@examplets // Define a test with options test('should subtract two numbers', { retry: 3 }, () => { expect(subtract(5, 2)).toBe(3); });
test
('Component', () => {
// Instantiate the component using Svelte's `mount` API const
const component: {
    $on?(type: string, callback: (e: any) => void): () => void;
    $set?(props: Partial<Record<string, any>>): void;
} & Record<string, any>
component
=
mount<Record<string, any>, {
    $on?(type: string, callback: (e: any) => void): () => void;
    $set?(props: Partial<Record<string, any>>): void;
} & Record<...>>(component: ComponentType<...> | Component<...>, options: MountOptions<...>): {
    ...;
} & Record<...>

Mounts a component to the given target and returns the exports and potentially the props (if compiled with accessors: true) of the component. Transitions will play during the initial render unless the intro option is set to false.

mount
(const Component: LegacyComponentTypeComponent, {
target: Document | Element | ShadowRoot

Target element where the component will be mounted.

target
: var document: Documentdocument.Document.body: HTMLElement

Specifies the beginning and end of the document body.

MDN Reference

body
, // `document` exists because of jsdom
props?: Record<string, any> | undefined

Component properties.

props
: { initial: numberinitial: 0 }
}); expect<string>(actual: string, message?: string): Assertion<string> (+1 overload)expect(var document: Documentdocument.Document.body: HTMLElement

Specifies the beginning and end of the document body.

MDN Reference

body
.InnerHTML.innerHTML: stringinnerHTML).JestAssertion<string>.toBe: <string>(expected: string) => voidtoBe('<button>0</button>');
// Click the button, then flush the changes so you can synchronously write expectations var document: Documentdocument.Document.body: HTMLElement

Specifies the beginning and end of the document body.

MDN Reference

body
.ParentNode.querySelector<"button">(selectors: "button"): HTMLButtonElement | null (+4 overloads)

Returns the first element that is a descendant of node that matches selectors.

MDN Reference

querySelector
('button').HTMLElement.click(): voidclick();
function flushSync(fn?: (() => void) | undefined): void

Synchronously flushes any pending state changes and those that result from it.

flushSync
();
expect<string>(actual: string, message?: string): Assertion<string> (+1 overload)expect(var document: Documentdocument.Document.body: HTMLElement

Specifies the beginning and end of the document body.

MDN Reference

body
.InnerHTML.innerHTML: stringinnerHTML).JestAssertion<string>.toBe: <string>(expected: string) => voidtoBe('<button>1</button>');
// Remove the component from the DOM function unmount(component: Record<string, any>): void

Unmounts a component that was previously mounted using mount or hydrate.

unmount
(
const component: {
    $on?(type: string, callback: (e: any) => void): () => void;
    $set?(props: Partial<Record<string, any>>): void;
} & Record<string, any>
component
);
});

雖然過程非常簡單,但它也是低階且有些脆弱的,因為組件的精確結構可能會經常變更。諸如 @testing-library/svelte 之類的工具可以協助您簡化測試。上面的測試可以像這樣重寫

component.test
import { function render<C extends unknown, Q extends Queries = typeof import("/vercel/path0/node_modules/.pnpm/@testing-library+dom@10.4.0/node_modules/@testing-library/dom/types/queries")>(Component: ComponentType<...>, options?: SvelteComponentOptions<C>, renderOptions?: RenderOptions<Q>): RenderResult<C, Q>

Render a component into the document.

@template{import('./component-types.js').Component} C
@template{import('@testing-library/dom').Queries} [Q=typeof import('@testing-library/dom').queries]
@paramComponent - The component to render.
@paramoptions - Customize how Svelte renders the component.
@paramrenderOptions - Customize how Testing Library sets up the document and binds queries.
@returnsThe rendered component and bound testing functions.
render
, const screen: Screen<typeof import("/vercel/path0/node_modules/.pnpm/@testing-library+dom@10.4.0/node_modules/@testing-library/dom/types/queries")>screen } from '@testing-library/svelte';
import
const userEvent: {
    readonly setup: typeof setupMain;
    readonly clear: typeof clear;
    readonly click: typeof click;
    readonly copy: typeof copy;
    ... 12 more ...;
    readonly tab: typeof tab;
}
userEvent
from '@testing-library/user-event';
import { const expect: ExpectStaticexpect, const test: TestAPI

Defines a test case with a given name and test function. The test function can optionally be configured with test options.

@paramname - The name of the test or a function that will be used as a test name.
@paramoptionsOrFn - Optional. The test options or the test function if no explicit name is provided.
@paramoptionsOrTest - Optional. The test function or options, depending on the previous parameters.
@throwsError If called inside another test function.
@examplets // Define a simple test test('should add two numbers', () => { expect(add(1, 2)).toBe(3); });
@examplets // Define a test with options test('should subtract two numbers', { retry: 3 }, () => { expect(subtract(5, 2)).toBe(3); });
test
} from 'vitest';
import
type Component = SvelteComponent<Record<string, any>, any, any>
const Component: LegacyComponentType
Component
from './Component.svelte';
test<object>(name: string | Function, fn?: TestFunction<object> | undefined, options?: number | TestOptions): void (+2 overloads)

Defines a test case with a given name and test function. The test function can optionally be configured with test options.

@paramname - The name of the test or a function that will be used as a test name.
@paramoptionsOrFn - Optional. The test options or the test function if no explicit name is provided.
@paramoptionsOrTest - Optional. The test function or options, depending on the previous parameters.
@throwsError If called inside another test function.
@examplets // Define a simple test test('should add two numbers', () => { expect(add(1, 2)).toBe(3); });
@examplets // Define a test with options test('should subtract two numbers', { retry: 3 }, () => { expect(subtract(5, 2)).toBe(3); });
test
('Component', async () => {
const const user: UserEventuser =
const userEvent: {
    readonly setup: typeof setupMain;
    readonly clear: typeof clear;
    readonly click: typeof click;
    readonly copy: typeof copy;
    ... 12 more ...;
    readonly tab: typeof tab;
}
userEvent
.setup: (options?: Options) => UserEvent

Start a “session” with userEvent. All APIs returned by this function share an input device state and a default configuration.

setup
();
render<SvelteComponent<Record<string, any>, any, any>, typeof import("/vercel/path0/node_modules/.pnpm/@testing-library+dom@10.4.0/node_modules/@testing-library/dom/types/queries")>(Component: ComponentType<...>, options?: SvelteComponentOptions<...> | undefined, renderOptions?: RenderOptions<...> | undefined): RenderResult<...>

Render a component into the document.

@template{import('./component-types.js').Component} C
@template{import('@testing-library/dom').Queries} [Q=typeof import('@testing-library/dom').queries]
@paramComponent - The component to render.
@paramoptions - Customize how Svelte renders the component.
@paramrenderOptions - Customize how Testing Library sets up the document and binds queries.
@returnsThe rendered component and bound testing functions.
render
(const Component: LegacyComponentTypeComponent);
const const button: HTMLElementbutton = const screen: Screen<typeof import("/vercel/path0/node_modules/.pnpm/@testing-library+dom@10.4.0/node_modules/@testing-library/dom/types/queries")>screen.getByRole<HTMLElement>(role: ByRoleMatcher, options?: ByRoleOptions | undefined): HTMLElement (+1 overload)getByRole('button'); expect<HTMLElement>(actual: HTMLElement, message?: string): Assertion<HTMLElement> (+1 overload)expect(const button: HTMLElementbutton).toHaveTextContent(0); await const user: UserEventuser.click: (element: Element) => Promise<void>click(const button: HTMLElementbutton); expect<HTMLElement>(actual: HTMLElement, message?: string): Assertion<HTMLElement> (+1 overload)expect(const button: HTMLElementbutton).toHaveTextContent(1); });

在撰寫涉及雙向繫結、上下文或程式碼片段 prop 的組件測試時,最好為您的特定測試建立一個包裝函式組件,並與之互動。@testing-library/svelte 包含一些範例

使用 Playwright 進行 E2E 測試

E2E(「端對端」的縮寫)測試可讓您透過使用者的角度測試完整的應用程式。本節使用 Playwright 作為範例,但您也可以使用其他解決方案,例如 CypressNightwatchJS

若要開始使用 Playwright,請透過 VS Code 擴充功能安裝,或使用 npm init playwright 從命令列安裝。當您執行 npx sv create 時,它也是設定 CLI 的一部分。

完成後,您應該會有一個 tests 資料夾和 Playwright 組態。您可能需要調整該組態,以告知 Playwright 在執行測試之前該怎麼做 — 主要是以特定埠啟動您的應用程式

playwright.config
const 
const config: {
    webServer: {
        command: string;
        port: number;
    };
    testDir: string;
    testMatch: RegExp;
}
config
= {
webServer: {
    command: string;
    port: number;
}
webServer
: {
command: stringcommand: 'npm run build && npm run preview', port: numberport: 4173 }, testDir: stringtestDir: 'tests', testMatch: RegExptestMatch: /(.+\.)?(test|spec)\.[jt]s/ }; export default
const config: {
    webServer: {
        command: string;
        port: number;
    };
    testDir: string;
    testMatch: RegExp;
}
config
;

您現在可以開始撰寫測試。這些測試完全不知道 Svelte 作為一個框架,因此您主要與 DOM 互動並撰寫斷言。

tests/hello-world.spec
import { import expectexpect, import testtest } from '@playwright/test';

import testtest('home page has expected h1', async ({ page }) => {
	await page: anypage.goto('/');
	await import expectexpect(page: anypage.locator('h1')).toBeVisible();
});

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