|
| 1 | +--- |
| 2 | +outline: deep |
| 3 | +title: Test Artifacts |
| 4 | +--- |
| 5 | + |
| 6 | +# Test Artifacts <Advanced /> <Version type="experimental">4.0.11</Version> <Experimental /> |
| 7 | + |
| 8 | +::: warning |
| 9 | +This is an advanced API. As a user, you most likely want to use [test annotations](/guide/test-annotations) to add notes or context to your tests instead. This is primarily used internally and by library authors. |
| 10 | +::: |
| 11 | + |
| 12 | +Test artifacts allow attaching or recording structured data, files, or metadata during test execution. This is a low-level feature primarily designed for: |
| 13 | + |
| 14 | +- Internal use ([`annotate`](/guide/test-annotations) is built on top of the artifact system) |
| 15 | +- Framework authors creating custom testing tools on top of Vitest |
| 16 | + |
| 17 | +Each artifact includes: |
| 18 | + |
| 19 | +- A type discriminator which is a unique identifier for the artifact type |
| 20 | +- Custom data, can be any relevant information |
| 21 | +- Optional attachments, either files or inline content associated with the artifact |
| 22 | +- A source code location indicating where the artifact was created |
| 23 | + |
| 24 | +Vitest automatically manages attachment serialization (files are copied to [`attachmentsDir`](/config/#attachmentsdir)) and injects source location metadata, so you can focus on the data you want to record. All artifacts **must** extend from [`TestArtifactBase`](#testartifactbase) and all attachments from [`TestAttachment`](#testattachment) to be correctly handled internally. |
| 25 | + |
| 26 | +## API |
| 27 | + |
| 28 | +### `recordArtifact` <Experimental /> {#recordartifact} |
| 29 | + |
| 30 | +::: warning |
| 31 | +`recordArtifact` is an experimental API. Breaking changes might not follow SemVer, please pin Vitest's version when using it. |
| 32 | + |
| 33 | +The API surface may change based on feedback. We encourage you to try it out and share your experience with the team. |
| 34 | +::: |
| 35 | + |
| 36 | +```ts |
| 37 | +function recordArtifact<Artifact extends TestArtifact>(task: Test, artifact: Artifact): Promise<Artifact> |
| 38 | +``` |
| 39 | + |
| 40 | +The `recordArtifact` function records an artifact during test execution and returns it. It expects a [task](/api/advanced/runner#tasks) as the first parameter and an object assignable to [`TestArtifact`](#testartifact) as the second. |
| 41 | + |
| 42 | +This function has to be used within a test, and the test has to still be running. Recording after test completion will throw an error. |
| 43 | + |
| 44 | +When an artifact is recorded on a test, it emits an `onTestArtifactRecord` runner event and a [`onTestCaseArtifactRecord` reporter event](/api/advanced/reporters#ontestcaseartifactrecord). |
| 45 | + |
| 46 | +Note: annotations, [even though they're built on top of this feature](#relationship-with-annotations), won't appear in the `task.artifacts` array for backwards compatibility reasons until the next major version. |
| 47 | + |
| 48 | +### `TestArtifact` |
| 49 | + |
| 50 | +The `TestArtifact` type is a union containing all artifacts Vitest can produce, including custom ones. All artifacts extend from [`TestArtifactBase`](#testartifactbase) |
| 51 | + |
| 52 | +### `TestArtifactBase` <Experimental /> {#testartifactbase} |
| 53 | + |
| 54 | +```ts |
| 55 | +export interface TestArtifactBase { |
| 56 | + /** File or data attachments associated with this artifact */ |
| 57 | + attachments?: TestAttachment[] |
| 58 | + /** Source location where this artifact was created */ |
| 59 | + location?: TestArtifactLocation |
| 60 | +} |
| 61 | +``` |
| 62 | + |
| 63 | +The `TestArtifactBase` interface is the base for all test artifacts. |
| 64 | + |
| 65 | +Extend this interface when creating custom test artifacts. Vitest automatically manages the `attachments` array and injects the `location` property to indicate where the artifact was created in your test code. |
| 66 | + |
| 67 | +### `TestAttachment` |
| 68 | + |
| 69 | +```ts |
| 70 | +export interface TestAttachment { |
| 71 | + /** MIME type of the attachment (e.g., 'image/png', 'text/plain') */ |
| 72 | + contentType?: string |
| 73 | + /** File system path to the attachment */ |
| 74 | + path?: string |
| 75 | + /** Inline attachment content as a string or raw binary data */ |
| 76 | + body?: string | Uint8Array |
| 77 | +} |
| 78 | +``` |
| 79 | + |
| 80 | +The `TestAttachment` interface represents a file or data attachment associated with a test artifact. |
| 81 | + |
| 82 | +Attachments can be either file-based (via `path`) or inline content (via `body`). The `contentType` helps consumers understand how to interpret the attachment data. |
| 83 | + |
| 84 | +### `TestArtifactLocation` |
| 85 | + |
| 86 | +```ts |
| 87 | +export interface TestArtifactLocation { |
| 88 | + /** Line number in the source file (1-indexed) */ |
| 89 | + line: number |
| 90 | + /** Column number in the line (1-indexed) */ |
| 91 | + column: number |
| 92 | + /** Path to the source file */ |
| 93 | + file: string |
| 94 | +} |
| 95 | +``` |
| 96 | + |
| 97 | +The `TestArtifactLocation` interface represents the source code location information for a test artifact. It indicates where in the source code the artifact originated from. |
| 98 | + |
| 99 | +### `TestArtifactRegistry` |
| 100 | + |
| 101 | +The `TestArtifactRegistry` interface is a registry for custom test artifact types. |
| 102 | + |
| 103 | +Augmenting this interface using [TypeScript's module augmentation feature](https://typescriptlang.org/docs/handbook/declaration-merging#module-augmentation) allows registering custom artifact types that tests can produce. |
| 104 | + |
| 105 | +Each custom artifact should extend [`TestArtifactBase`](#testartifactbase) and include a unique `type` discriminator property. |
| 106 | + |
| 107 | +Here are a few guidelines or best practices to follow: |
| 108 | + |
| 109 | +- Try using a `Symbol` as the **registry key** to guarantee uniqueness |
| 110 | +- The `type` property should follow the pattern `'package-name:artifact-name'`, **`'internal:'` is a reserved prefix** |
| 111 | +- Use `attachments` to include files or data; extend [`TestAttachment`](#testattachment) for custom metadata |
| 112 | +- `location` property is automatically injected |
| 113 | + |
| 114 | +## Custom Artifacts |
| 115 | + |
| 116 | +To use and manage artifacts in a type-safe manner, you need to create its type and register it: |
| 117 | + |
| 118 | +```ts |
| 119 | +import type { TestArtifactBase, TestAttachment } from 'vitest' |
| 120 | +
|
| 121 | +interface A11yReportAttachment extends TestAttachment { |
| 122 | + contentType: 'text/html' |
| 123 | + path: string |
| 124 | +} |
| 125 | +
|
| 126 | +interface AccessibilityArtifact extends TestArtifactBase { |
| 127 | + type: 'a11y:report' |
| 128 | + passed: boolean |
| 129 | + wcagLevel: 'A' | 'AA' | 'AAA' |
| 130 | + attachments: [A11yReportAttachment] |
| 131 | +} |
| 132 | +
|
| 133 | +const a11yReportKey = Symbol('report') |
| 134 | +
|
| 135 | +declare module 'vitest' { |
| 136 | + interface TestArtifactRegistry { |
| 137 | + [a11yReportKey]: AccessibilityArtifact |
| 138 | + } |
| 139 | +} |
| 140 | +``` |
| 141 | + |
| 142 | +As long as the types are assignable to their bases and don't have errors, everything should work fine and you should be able to record artifacts using [`recordArtifact`](#recordartifact): |
| 143 | + |
| 144 | +```ts |
| 145 | +async function toBeAccessible( |
| 146 | + this: MatcherState, |
| 147 | + actual: Element, |
| 148 | + wcagLevel: 'A' | 'AA' | 'AAA' = 'AA' |
| 149 | +): AsyncExpectationResult { |
| 150 | + const report = await runAccessibilityAudit(actual, wcagLevel) |
| 151 | +
|
| 152 | + await recordArtifact(this.task, { |
| 153 | + type: 'a11y:report', |
| 154 | + passed: report.violations.length === 0, |
| 155 | + wcagLevel, |
| 156 | + attachments: [{ |
| 157 | + contentType: 'text/html', |
| 158 | + path: report.path, |
| 159 | + }], |
| 160 | + }) |
| 161 | +
|
| 162 | + return { |
| 163 | + pass: violations.length === 0, |
| 164 | + message: () => `Found ${report.violations.length} accessibility violation(s)` |
| 165 | + } |
| 166 | +} |
| 167 | +``` |
| 168 | + |
| 169 | +## Relationship with Annotations |
| 170 | + |
| 171 | +Test annotations are built on top of the artifact system. When using annotations in tests, they create `internal:annotation` artifacts under the hood. However, annotations are: |
| 172 | + |
| 173 | +- Simpler to use |
| 174 | +- Designed for end-users, not developers |
| 175 | + |
| 176 | +Use annotations if you just want to add notes to your tests. Use artifacts if you need custom data. |
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