Feature: adds aria-expanded filter to *ByRole (testing-library#821)

Co-authored-by: Luis Rodrigues <luis.rodrigues@springernature.com>
Co-authored-by: Sebastian Silbermann <silbermann.sebastian@gmail.com>

src/__tests__/ariaAttributes.js

@@ -27,6 +27,15 @@ test('`checked` throws on unsupported roles', () => {
   )
 })
 
+test('`expanded` throws on unsupported roles', () => {
+  const {getByRole} = render(`<h1 aria-expanded="true">Heading</h1>`)
+  expect(() =>
+    getByRole('heading', {expanded: true}),
+  ).toThrowErrorMatchingInlineSnapshot(
+    `"\\"aria-expanded\\" is not supported on role \\"heading\\"."`,
+  )
+})
+
 test('`checked: true|false` matches `checked` checkboxes', () => {
   const {getByRole} = renderIntoDocument(
     `<div>
@@ -202,3 +211,25 @@ test('`level` throws on unsupported roles', () => {
     `"Role \\"button\\" cannot have \\"level\\" property."`,
   )
 })
+
+test('`expanded: true|false` matches `expanded` buttons', () => {
+  const {getByRole} = renderIntoDocument(
+    `<div>
+      <button aria-expanded="true" />
+      <button aria-expanded="false" />
+    </div>`,
+  )
+  expect(getByRole('button', {expanded: true})).toBeInTheDocument()
+  expect(getByRole('button', {expanded: false})).toBeInTheDocument()
+})
+
+test('`expanded: true|false` matches `expanded` elements with proper role', () => {
+  const {getByRole} = renderIntoDocument(
+    `<div>
+      <span role="button" aria-expanded="true">✔</span>
+      <span role="button" aria-expanded="false">𝒙</span>
+    </div>`,
+  )
+  expect(getByRole('button', {expanded: true})).toBeInTheDocument()
+  expect(getByRole('button', {expanded: false})).toBeInTheDocument()
+})

src/queries/role.js

@@ -4,6 +4,7 @@ import {
   computeAriaSelected,
   computeAriaChecked,
   computeAriaPressed,
+  computeAriaExpanded,
   computeHeadingLevel,
   getImplicitAriaRoles,
   prettyRoles,
@@ -35,6 +36,7 @@ function queryAllByRole(
     checked,
     pressed,
     level,
+    expanded,
   } = {},
 ) {
   checkContainerType(container)
@@ -69,6 +71,13 @@ function queryAllByRole(
     }
   }
 
+  if (expanded !== undefined) {
+    // guard against unknown roles
+    if (allRoles.get(role)?.props['aria-expanded'] === undefined) {
+      throw new Error(`"aria-expanded" is not supported on role "${role}".`)
+    }
+  }
+
   const subtreeIsInaccessibleCache = new WeakMap()
   function cachedIsSubtreeInaccessible(element) {
     if (!subtreeIsInaccessibleCache.has(element)) {
@@ -115,6 +124,9 @@ function queryAllByRole(
       if (pressed !== undefined) {
         return pressed === computeAriaPressed(element)
       }
+      if (expanded !== undefined) {
+        return expanded === computeAriaExpanded(element)
+      }
       if (level !== undefined) {
         return level === computeHeadingLevel(element)
       }

src/role-helpers.js

@@ -247,6 +247,15 @@ function computeAriaPressed(element) {
   return checkBooleanAttribute(element, 'aria-pressed')
 }
 
+/**
+ * @param {Element} element -
+ * @returns {boolean | undefined} - false/true if (not)expanded, undefined if not expand-able
+ */
+function computeAriaExpanded(element) {
+  // https://www.w3.org/TR/wai-aria-1.1/#aria-expanded
+  return checkBooleanAttribute(element, 'aria-expanded')
+}
+
 function checkBooleanAttribute(element, attribute) {
   const attributeValue = element.getAttribute(attribute)
   if (attributeValue === 'true') {
@@ -292,5 +301,6 @@ export {
   computeAriaSelected,
   computeAriaChecked,
   computeAriaPressed,
+  computeAriaExpanded,
   computeHeadingLevel,
 }

types/queries.d.ts

@@ -88,6 +88,11 @@ export interface ByRoleOptions extends MatcherOptions {
    * pressed in the accessibility tree, i.e., `aria-pressed="true"`
    */
   pressed?: boolean
+  /**
+   * If true only includes elements in the query set that are marked as
+   * expanded in the accessibility tree, i.e., `aria-expanded="true"`
+   */
+  expanded?: boolean
   /**
    * Includes elements with the `"heading"` role matching the indicated level,
    * either by the semantic HTML heading elements `<h1>-<h6>` or matching