docs: add toHaveAccessibleErrorMessage API

docs/src/api/class-locatorassertions.md

@@ -1217,6 +1217,56 @@ Expected accessible description.
 * since: v1.44
 
 
+## async method: LocatorAssertions.toHaveAccessibleErrorMessage
+* since: v1.50
+* langs:
+  - alias-java: hasAccessibleErrorMessage
+
+Ensures the [Locator] points to an element with a given [accessible error message](https://www.w3.org/TR/wai-aria-1.2/#aria-errormessage).
+
+**Usage**
+
+```js
+const locator = page.getByTestId('username-input');
+await expect(locator).toHaveAccessibleErrorMessage('Username is required.');
+```
+
+```java
+Locator locator = page.getByTestId("username-input");
+assertThat(locator).hasAccessibleErrorMessage("Username is required.");
+```
+
+```python async
+locator = page.get_by_test_id("username-input")
+await expect(locator).to_have_accessible_error_message("Username is required.")
+```
+
+```python sync
+locator = page.get_by_test_id("username-input")
+expect(locator).to_have_accessible_error_message("Username is required.")
+```
+
+```csharp
+var locator = Page.GetByTestId("username-input");
+await Expect(locator).ToHaveAccessibleErrorMessageAsync("Username is required.");
+```
+
+### param: LocatorAssertions.toHaveAccessibleErrorMessage.errorMessage
+* since: v1.45
+- `errorMessage` <[string]|[RegExp]>
+
+Expected accessible error message.
+
+### option: LocatorAssertions.toHaveAccessibleErrorMessage.timeout = %%-js-assertions-timeout-%%
+* since: v1.45
+
+### option: LocatorAssertions.toHaveAccessibleErrorMessage.timeout = %%-csharp-java-python-assertions-timeout-%%
+* since: v1.45
+
+### option: LocatorAssertions.toHaveAccessibleErrorMessage.ignoreCase = %%-assertions-ignore-case-%%
+* since: v1.45
+
+
 ## async method: LocatorAssertions.toHaveAccessibleName
 * since: v1.44
 * langs:

packages/playwright/types/test.d.ts

@@ -7903,6 +7903,34 @@ interface LocatorAssertions {
     timeout?: number;
   }): Promise<void>;
 
+  /**
+   * Ensures the [Locator](https://playwright.dev/docs/api/class-locator) points to an element with a given
+   * [accessible error message](https://www.w3.org/TR/wai-aria-1.2/#aria-errormessage).
+   *
+   * **Usage**
+   *
+   * ```js
+   * const locator = page.getByTestId('username-input');
+   * await expect(locator).toHaveAccessibleErrorMessage('Username is required.');
+   * ```
+   *
+   * @param errorMessage Expected accessible error message.
+   * @param options
+   */
+  toHaveAccessibleErrorMessage(errorMessage: string|RegExp, options?: {
+    /**
+     * Whether to perform case-insensitive match.
+     * [`ignoreCase`](https://playwright.dev/docs/api/class-locatorassertions#locator-assertions-to-have-accessible-error-message-option-ignore-case)
+     * option takes precedence over the corresponding regular expression flag if specified.
+     */
+    ignoreCase?: boolean;
+
+    /**
+     * Time to retry the assertion for in milliseconds. Defaults to `timeout` in `TestConfig.expect`.
+     */
+    timeout?: number;
+  }): Promise<void>;
+
   /**
    * Ensures the [Locator](https://playwright.dev/docs/api/class-locator) points to an element with a given
    * [accessible name](https://w3c.github.io/accname/#dfn-accessible-name).