Add visual regression tests (#994)

Co-authored-by: Roman Pronskiy <roman@pronskiy.com>
Co-authored-by: Derick Rethans <derick@php.net>

tests/Visual/SmokeTest.spec.ts

@@ -0,0 +1,63 @@
+import {expect, test} from '@playwright/test';
+
+export type TestPageOptions = {
+    path: string
+    options?: object
+    evaluate?: () => any
+}
+
+const items: TestPageOptions[] = [
+    {
+        path: 'index.php',
+        evaluate: () => {
+            const selector = document.querySelector('.elephpants');
+            selector.remove()
+        }
+    },
+    {
+        path: 'archive/1998.php',
+        evaluate: () => {
+            const selector = document.querySelector('.elephpants');
+            selector.remove()
+        }
+    },
+    {path: 'releases/8_3_6.php'},
+    {path: 'releases/8.0/index.php'},
+    {path: 'releases/8.1/index.php'},
+    {path: 'releases/8.2/index.php'},
+    {path: 'releases/8.3/index.php'},
+    {path: 'manual/index.php'},
+    {path: 'manual/php5.php'},
+    {
+        path: 'conferences/index.php',
+        options: {
+            fullPage: false,
+        }
+    },
+]
+
+for (const item of items) {
+    test(`testing with ${item.path}`, async ({page}, testInfo) => {
+        testInfo.snapshotSuffix = '';
+
+        const httpHost = process.env.HTTP_HOST
+
+        if (typeof httpHost !== 'string') {
+            throw new Error('Environment variable "HTTP_HOST" is not set.')
+        }
+
+        await page.goto(`${httpHost}/${item.path}`)
+
+        if (typeof item.evaluate === 'function') {
+            await page.evaluate(item.evaluate)
+        }
+
+        await expect(page).toHaveScreenshot(
+            `tests/screenshots/${item.path}.png`,
+            item.options ?? {
+                fullPage: true,
+                timeout: 10000,
+            }
+        )
+    })
+}