MDL-78806 behat: Create a step that for checking the page title

Create a Behat step "the page title should contain ':title'" to check
the page title.

lib/tests/behat/behat_general.php

@@ -2189,4 +2189,36 @@ EOF;
         }
     }
 
+    /**
+     * Check that the page title contains a given string.
+     *
+     * @Given the page title should contain ":title"
+     * @param string $title The string that should be present on the page title.
+     */
+    public function the_page_title_should_contain(string $title): void {
+        $session = $this->getSession();
+        if ($this->running_javascript()) {
+            // When running on JS, the page title can be changed via JS, so it's more reliable to get the actual page title via JS.
+            $actualtitle = $session->evaluateScript("return document.title");
+        } else {
+            $titleelement = $session->getPage()->find('css', 'head title');
+            if ($titleelement === null) {
+                // Throw an exception if a page title is not present on the page.
+                throw new ElementNotFoundException(
+                    $this->getSession(),
+                    '<title> element',
+                    'css',
+                    'head title'
+                );
+            }
+            $actualtitle = $titleelement->getText();
+        }
+
+        if (strpos($actualtitle, $title) === false) {
+            throw new ExpectationException(
+                "'$title' was not found from the current page title '$actualtitle'",
+                $session
+            );
+        }
+    }
 }

lib/upgrade.txt

@@ -1,6 +1,11 @@
 This files describes API changes in core libraries and APIs,
 information provided here is intended especially for developers.
 
+=== 3.11.17 ===
+* New Behat step \behat_general::the_page_title_should_contain() has been added to allow checking of page titles. You can use this
+  when writing feature files to check that the page title contains the expected string.
+  e.g. `And the page title should contain "Some title"`
+
 === 3.11.15 ===
 * Added a new parameter in address_in_subnet to give us the ability to check for 0.0.0.0 or not.