e2e test - Data Columns Names (#8105)

### QA Notes

This PR creates `data-columns.test.ts` test suite in order to verify
data column names can be consistently generated in Positron's Data
Explorer.

It covers most cases, including edge cases, and addresses #5915 .

@:win @:web @:data-explorer

---------

Co-authored-by: Chris Mead <[email protected]>

Author: rodrigosf672

test/e2e/pages/dataExplorer.ts

@@ -328,4 +328,18 @@ export class DataExplorer {
 			await expect(hoverTooltip).toContainText('Missing Values');
 		});
 	}
+
+	// Note that herein we're getting the column headers from the filter popup, hence why new function and const.
+	async getColumnHeaders(): Promise<string[]> {
+		const headersLocator = this.code.driver.page.locator('div.column-name');
+		return await headersLocator.allInnerTexts();
+	}
+
+	async verifyColumnHeaders(expectedHeaders: string[]) {
+		await test.step('Verify column headers', async () => {
+			const actualHeaders = await this.getColumnHeaders();
+			const missing = expectedHeaders.filter(item => !actualHeaders.includes(item));
+			expect(missing).toEqual([]); // Will throw if any are missing
+		});
+	}
 }

test/e2e/tests/data-explorer/data-columns.test.ts

@@ -0,0 +1,33 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (C) 2025 Posit Software, PBC. All rights reserved.
+ *  Licensed under the Elastic License 2.0. See LICENSE.txt for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import { test, tags } from '../_test.setup';
+import { expectedColumnNames } from './helpers/expected_columns';
+
+test.use({
+	suiteId: __filename
+});
+
+test.describe('Data Explorer: Column Names', { tag: [tags.WEB, tags.WIN, tags.DATA_EXPLORER] }, () => {
+
+	test('Verify data columns - Python', async function ({ app, python, openDataFile }) {
+		await openDataFile('data-files/data_explorer/data_columns.csv');
+		await app.workbench.dataExplorer.addFilterButton.click();
+		await app.workbench.dataExplorer.selectColumnButton.click();
+		await app.workbench.dataExplorer.verifyColumnHeaders(expectedColumnNames);
+	});
+
+});
+
+/* Add this after test.describe if there is a need to escape from the filter and delete all sessions for clean-up.
+	test.afterEach(async ({ app, page }) => {
+		await page.getByRole('button', { name: 'Select Column' }).focus();
+		await page.keyboard.press('Escape');
+		await page.keyboard.press('Escape');
+		await expect(page.locator('.positron-modal-popup')).toHaveCount(0);
+		await app.workbench.console.clearButton.click();
+		await app.workbench.sessions.deleteAll();
+	});
+*/

test/e2e/tests/data-explorer/helpers/expected_columns.ts

@@ -0,0 +1,31 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (C) 2025 Posit Software, PBC. All rights reserved.
+ *  Licensed under the Elastic License 2.0. See LICENSE.txt for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+// This helper contains expected column names and a Python script that generates a data frame with similar names.
+export const expectedColumnNames = [
+	'normal_name',
+	'leading_space',
+	'trailing_space',
+	'both',
+	'column04',
+	'123numeric_start',
+	'!@#symbols',
+	'中文字符',
+	'naïve_column',
+	'name,with,comma',
+	'"quoted"',
+	'multiline header',
+	'supercalifragilisticexpialidocious_column_name_that_is_really_really_long_to_test_limits',
+	'whitespace (tab)',
+	'duplicate',
+	'duplicate_1',
+	'Nombre_Español',
+	'ID_Único',
+	'Nome_Português',
+	'Número_do_Pedido',
+	'اسم_عربي',
+	'رمز_المنتج',
+];
+