Add parameter for Axe context

https://www.deque.com/axe/core-documentation/api-documentation/#context-parameter

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## Unreleased
 
+- [new] Add parameter for Axe `context` [#98](https://github.com/chanzuckerberg/axe-storybook-testing/pull/98)
+
 ## 8.1.0
 
 - [new] Add `--port` option [#97](https://github.com/chanzuckerberg/axe-storybook-testing/pull/97)

README.md

@@ -17,6 +17,7 @@ If there are any violations, information about them will be printed, and the com
   - [disabledRules](#disabledrules)
   - [mode](#mode)
   - [runOptions](#runoptions)
+  - [context](#context)
   - [config](#config)
   - [skip](#skip)
   - [timeout](#timeout)
@@ -167,6 +168,22 @@ export const SomeStory = {
 }
 ```
 
+### context
+
+[Axe context](https://www.deque.com/axe/core-documentation/api-documentation/#context-parameter), which is passed to `axe.run`. Useful for including or excluding elements from the tests.
+
+```jsx
+export const SomeStory = {
+  parameters: {
+    axe: {
+      context: {
+        exclude: '.foo',
+      },
+    }
+  }
+}
+```
+
 ### config
 
 Axe configuration, which is passed to [axe.configure](https://www.deque.com/axe/core-documentation/api-documentation/#api-name-axeconfigure).

demo/src/advanced.stories.jsx

@@ -21,3 +21,26 @@ export const branding = {
     },
   },
 };
+
+// Test out passing context to `axe.run`.
+export const multipleParts = {
+  render: () => (
+    <div>
+      <div id="a">
+        <button style={{backgroundColor: 'red', color: 'hotpink'}}>
+          hello A
+        </button>
+      </div>
+      <div id="b">
+        <button style={{backgroundColor: 'red', color: 'hotpink'}}>
+          hello B
+        </button>
+      </div>
+    </div>
+  ),
+  parameters: {
+    axe: {
+      context: '#a',
+    },
+  },
+};

index.d.ts

@@ -1,4 +1,9 @@
-import type {RunOptions, Spec} from 'axe-core';
+import type {
+  RunOptions,
+  SerialContextObject,
+  SerialFrameSelector,
+  Spec,
+} from 'axe-core';
 
 export declare type AxeParams = {
   /**
@@ -26,6 +31,11 @@ export declare type AxeParams = {
    * @see https://www.deque.com/axe/core-documentation/api-documentation/#options-parameter
    */
   runOptions?: RunOptions;
+  /**
+   * Context passed to `axe.run`.
+   * @see https://www.deque.com/axe/core-documentation/api-documentation/#context-parameter
+   */
+  context?: SerialFrameSelector | SerialFrameSelector[] | SerialContextObject;
   /**
    * Config passed to `axe.configure`.
    */

src/ProcessedStory.ts

@@ -1,11 +1,13 @@
 import type {RunOptions, Spec} from 'axe-core';
 import {z as zod} from 'zod';
+import type {Context} from './browser/AxePage';
 import type {StorybookStory} from './browser/StorybookPage';
 
 type Params = {
   disabledRules: string[];
   mode: 'off' | 'warn' | 'error';
   runOptions?: RunOptions;
+  context?: Context;
   config?: Spec;
   skip: boolean;
   timeout: number;
@@ -42,6 +44,9 @@ export default class ProcessedStory {
         rawStory.parameters?.axe?.runOptions,
         rawStory,
       ),
+      context: normalizeContext(rawStory.parameters?.axe?.context, rawStory) as
+        | Context
+        | undefined,
       config: normalizeConfig(rawStory.parameters?.axe?.config, rawStory),
     };
   }
@@ -75,6 +80,14 @@ export default class ProcessedStory {
     return this.parameters.runOptions;
   }
 
+  /**
+   * Context passed to `axe.run`.
+   * @see https://www.deque.com/axe/core-documentation/api-documentation/#context-parameter
+   */
+  get context() {
+    return this.parameters.context;
+  }
+
   /**
    * All optional config used to configure axe-core. Passed to `axe.configure`.
    * @see https://www.deque.com/axe/core-documentation/api-documentation/#api-name-axeconfigure
@@ -138,6 +151,14 @@ const runOptionsSchema = zod.optional(
   }),
 );
 
+const contextSchema = zod
+  .union([
+    zod.string(),
+    zod.array(zod.string()),
+    zod.record(zod.string(), zod.any()),
+  ])
+  .optional();
+
 const configSchema = zod.object({}).passthrough().optional();
 
 function normalizeSkip(skip: unknown, rawStory: StorybookStory) {
@@ -175,6 +196,14 @@ function normalizeRunOptions(runOptions: unknown, rawStory: StorybookStory) {
   );
 }
 
+function normalizeContext(config: unknown, rawStory: StorybookStory) {
+  return parseWithFriendlyError(
+    () => contextSchema.parse(config),
+    rawStory,
+    'context',
+  );
+}
+
 function normalizeConfig(config: unknown, rawStory: StorybookStory) {
   return parseWithFriendlyError(
     () => configSchema.parse(config),

src/Result.ts

@@ -29,6 +29,7 @@ export default class Result {
       page,
       disabledRules,
       story.runOptions,
+      story.context,
       story.config,
     );
     return new Result(axeResults.violations);

src/browser/AxePage.ts

@@ -1,6 +1,18 @@
-import type {AxeResults, RuleObject, RunOptions, Spec} from 'axe-core';
+import type {
+  AxeResults,
+  SerialContextObject,
+  SerialFrameSelector,
+  RuleObject,
+  RunOptions,
+  Spec,
+} from 'axe-core';
 import type {Page} from 'playwright';
 
+export type Context =
+  | SerialFrameSelector
+  | SerialFrameSelector[]
+  | SerialContextObject;
+
 /**
  * Prepare a page for running axe on it.
  */
@@ -17,20 +29,24 @@ export function analyze(
   page: Page,
   disabledRules: string[] = [],
   runOptions: RunOptions = {},
+  context?: Context,
   config?: Spec,
 ): Promise<AxeResults> {
   return page.evaluate(runAxe, {
     options: getRunOptions(runOptions, disabledRules),
     config,
+    context,
   });
 }
 
 function runAxe({
-  options,
   config,
+  context,
+  options,
 }: {
-  options: RunOptions;
   config?: Spec;
+  context?: Context;
+  options: RunOptions;
 }): Promise<AxeResults> {
   // eslint-disable-next-line @typescript-eslint/ban-ts-comment
   // @ts-ignore This function executes in a browser context.
@@ -49,7 +65,7 @@ function runAxe({
 
     // eslint-disable-next-line @typescript-eslint/ban-ts-comment
     // @ts-ignore This function executes in a browser context.
-    return window.axe.run(document, options);
+    return window.axe.run(context || document, options);
   });
 }