3e: Add more assertions

Add more assertions to ensure that the correct page title is returned as
well as some text on the page.

This fails as the expected test is not returned.

web/modules/custom/my_module/tests/src/Functional/BlogPageTest.php

@@ -21,6 +21,8 @@ class BlogPageTest extends BrowserTestBase {
     $session = $this->assertSession();
 
     $session->statusCodeEquals(Response::HTTP_OK);
+    $session->responseContains('<h1>Blog</h1>');
+    $session->pageTextContains('Welcome to my blog!');
   }
 
 }