feat: implement toBeSelected matcher

src/helpers/accessiblity.ts

@@ -176,6 +176,13 @@ export function getAccessibilityCheckedState(
   return ariaChecked ?? accessibilityState?.checked;
 }
 
+export function getAccessibilitySelectedState(
+  element: ReactTestInstance
+): NonNullable<AccessibilityState['selected']> {
+  const { accessibilityState, 'aria-selected': ariaSelected } = element.props;
+  return ariaSelected ?? accessibilityState?.selected ?? false;
+}
+
 export function getAccessibilityValue(
   element: ReactTestInstance
 ): AccessibilityValue | undefined {

src/matchers/__tests__/to-be-selected.test.tsx

@@ -0,0 +1,96 @@
+import * as React from 'react';
+import { View } from 'react-native';
+import { render, screen } from '../..';
+import '../extend-expect';
+
+test('.toBeSelected() basic case', () => {
+  render(
+    <>
+      <View testID="selected" accessibilityState={{ selected: true }} />
+      <View testID="selected-aria" aria-selected />
+      <View testID="not-selected" accessibilityState={{ selected: false }} />
+      <View testID="not-selected-aria" aria-selected={false} />
+      <View testID="default" />
+    </>
+  );
+
+  expect(screen.getByTestId('selected')).toBeSelected();
+  expect(screen.getByTestId('selected-aria')).toBeSelected();
+  expect(screen.getByTestId('not-selected')).not.toBeSelected();
+  expect(screen.getByTestId('not-selected-aria')).not.toBeSelected();
+  expect(screen.getByTestId('default')).not.toBeSelected();
+});
+
+test('.toBeSelected() error messages', () => {
+  render(
+    <>
+      <View testID="selected" accessibilityState={{ selected: true }} />
+      <View testID="selected-aria" aria-selected />
+      <View testID="not-selected" accessibilityState={{ selected: false }} />
+      <View testID="not-selected-aria" aria-selected={false} />
+      <View testID="default" />
+    </>
+  );
+
+  expect(() => expect(screen.getByTestId('selected')).not.toBeSelected())
+    .toThrowErrorMatchingInlineSnapshot(`
+    "expect(element).not.toBeSelected()
+
+    Received element is selected
+      <View
+        accessibilityState={
+          {
+            "selected": true,
+          }
+        }
+        testID="selected"
+      />"
+  `);
+
+  expect(() => expect(screen.getByTestId('selected-aria')).not.toBeSelected())
+    .toThrowErrorMatchingInlineSnapshot(`
+    "expect(element).not.toBeSelected()
+
+    Received element is selected
+      <View
+        aria-selected={true}
+        testID="selected-aria"
+      />"
+  `);
+
+  expect(() => expect(screen.getByTestId('not-selected')).toBeSelected())
+    .toThrowErrorMatchingInlineSnapshot(`
+    "expect(element).toBeSelected()
+
+    Received element is not selected
+      <View
+        accessibilityState={
+          {
+            "selected": false,
+          }
+        }
+        testID="not-selected"
+      />"
+  `);
+
+  expect(() => expect(screen.getByTestId('not-selected-aria')).toBeSelected())
+    .toThrowErrorMatchingInlineSnapshot(`
+    "expect(element).toBeSelected()
+
+    Received element is not selected
+      <View
+        aria-selected={false}
+        testID="not-selected-aria"
+      />"
+  `);
+
+  expect(() => expect(screen.getByTestId('default')).toBeSelected())
+    .toThrowErrorMatchingInlineSnapshot(`
+    "expect(element).toBeSelected()
+
+    Received element is not selected
+      <View
+        testID="default"
+      />"
+  `);
+});

src/matchers/extend-expect.d.ts

@@ -7,6 +7,7 @@ export interface JestNativeMatchers<R> {
   toBeEmptyElement(): R;
   toBeEnabled(): R;
   toBePartiallyChecked(): R;
+  toBeSelected(): R;
   toBeVisible(): R;
   toHaveDisplayValue(expectedValue: TextMatch, options?: TextMatchOptions): R;
   toHaveProp(name: string, expectedValue?: unknown): R;

src/matchers/extend-expect.ts

@@ -5,6 +5,7 @@ import { toBeChecked } from './to-be-checked';
 import { toBeDisabled, toBeEnabled } from './to-be-disabled';
 import { toBeEmptyElement } from './to-be-empty-element';
 import { toBePartiallyChecked } from './to-be-partially-checked';
+import { toBeSelected } from './to-be-selected';
 import { toBeVisible } from './to-be-visible';
 import { toHaveDisplayValue } from './to-have-display-value';
 import { toHaveProp } from './to-have-prop';
@@ -17,6 +18,7 @@ expect.extend({
   toBeEmptyElement,
   toBeEnabled,
   toBePartiallyChecked,
+  toBeSelected,
   toBeVisible,
   toHaveDisplayValue,
   toHaveProp,

src/matchers/index.tsx

@@ -7,3 +7,4 @@ export { toBeVisible } from './to-be-visible';
 export { toHaveDisplayValue } from './to-have-display-value';
 export { toHaveProp } from './to-have-prop';
 export { toHaveTextContent } from './to-have-text-content';
+export { toBeSelected } from './to-be-selected';

src/matchers/to-be-selected.ts

@@ -0,0 +1,24 @@
+import { ReactTestInstance } from 'react-test-renderer';
+import { matcherHint } from 'jest-matcher-utils';
+import { getAccessibilitySelectedState } from '../helpers/accessiblity';
+import { checkHostElement, formatElement } from './utils';
+
+export function toBeSelected(
+  this: jest.MatcherContext,
+  element: ReactTestInstance
+) {
+  checkHostElement(element, toBeSelected, this);
+
+  return {
+    pass: getAccessibilitySelectedState(element),
+    message: () => {
+      const is = this.isNot ? 'is' : 'is not';
+      return [
+        matcherHint(`${this.isNot ? '.not' : ''}.toBeSelected`, 'element', ''),
+        '',
+        `Received element ${is} selected`,
+        formatElement(element),
+      ].join('\n');
+    },
+  };
+}