test: print form and heading summary on OAuth flow failure

When GitHub serves an unexpected page (e.g. a new 2FA re-verification
variant we do not yet recognize), the test now prints the form actions,
input names, and h1/h2 text in the failure message. Form values and
body content are not emitted, so nothing sensitive lands in CI logs.

Signed-off-by: Oleksander Piskun <oleksandr2088@icloud.com>

Author: oleksandr-nc

tests/integration/GitHubHtml.php

@@ -106,4 +106,45 @@ public static function extractFormInputs(DOMXPath $selector, DOMElement $form):
 
 		return $formParams;
 	}
+
+	/**
+	 * Summarize the forms and headings on a page for failure diagnostics.
+	 * Emits form actions and input names (never values) plus h1/h2 text,
+	 * so CI logs show what GitHub actually returned without leaking tokens.
+	 */
+	public static function describePage(DOMXPath $selector): string {
+		$parts = [];
+
+		$forms = $selector->query('//form');
+		if ($forms !== false) {
+			foreach ($forms as $form) {
+				if (!$form instanceof DOMElement) {
+					continue;
+				}
+				$action = $form->getAttribute('action');
+				$inputNodes = $selector->query('.//input[@name] | .//button[@name]', $form);
+				$names = [];
+				if ($inputNodes !== false) {
+					foreach ($inputNodes as $input) {
+						if ($input instanceof DOMElement) {
+							$names[] = $input->getAttribute('name');
+						}
+					}
+				}
+				$parts[] = 'form(action=' . ($action === '' ? '<empty>' : $action) . ', inputs=[' . implode(',', $names) . '])';
+			}
+		}
+
+		$headings = $selector->query('//h1 | //h2');
+		if ($headings !== false) {
+			foreach ($headings as $heading) {
+				$text = trim($heading->textContent);
+				if ($text !== '') {
+					$parts[] = $heading->nodeName . '=' . mb_substr($text, 0, 120);
+				}
+			}
+		}
+
+		return $parts === [] ? '<no forms or headings found>' : implode(' | ', $parts);
+	}
 }

tests/integration/GithubOauthIntegrationTest.php

@@ -261,7 +261,11 @@ private function interpretAuthenticatedResponse(string $body, string $finalUrl,
 			$this->fail('GitHub returned the sign-in page after the ' . $step . ' step. This usually means the authenticated session was not established or cookies were not kept. Final URL: ' . $finalUrl);
 		}
 
-		$this->fail('GitHub completed the ' . $step . ' step but neither a 2FA form, an authorize form, nor a callback redirect with code was found. Final URL: ' . $finalUrl . '. Page title: ' . $title);
+		$this->fail(
+			'GitHub completed the ' . $step . ' step but neither a 2FA form, an authorize form, nor a callback redirect with code was found. '
+			. 'Final URL: ' . $finalUrl . '. Page title: ' . $title . '. '
+			. 'Page: ' . GitHubHtml::describePage($selector)
+		);
 	}
 
 	private function loginToGitHub(string $authorizeUrl): array {