--- /dev/null
+<?php
+
+namespace Drupal\Tests;
+
+use Drupal\Component\Utility\Random;
+
+/**
+ * Provides random generator utility methods.
+ */
+trait RandomGeneratorTrait {
+
+ /**
+ * The random generator.
+ *
+ * @var \Drupal\Component\Utility\Random
+ */
+ protected $randomGenerator;
+
+ /**
+ * Generates a pseudo-random string of ASCII characters of codes 32 to 126.
+ *
+ * Do not use this method when special characters are not possible (e.g., in
+ * machine or file names that have already been validated); instead, use
+ * \Drupal\simpletest\TestBase::randomMachineName(). If $length is greater
+ * than 3 the random string will include at least one ampersand ('&') and
+ * at least one greater than ('>') character to ensure coverage for special
+ * characters and avoid the introduction of random test failures.
+ *
+ * @param int $length
+ * Length of random string to generate.
+ *
+ * @return string
+ * Pseudo-randomly generated unique string including special characters.
+ *
+ * @see \Drupal\Component\Utility\Random::string()
+ */
+ public function randomString($length = 8) {
+ if ($length < 4) {
+ return $this->getRandomGenerator()->string($length, TRUE, [$this, 'randomStringValidate']);
+ }
+
+ // To prevent the introduction of random test failures, ensure that the
+ // returned string contains a character that needs to be escaped in HTML by
+ // injecting an ampersand into it.
+ $replacement_pos = floor($length / 2);
+ // Remove 2 from the length to account for the ampersand and greater than
+ // characters.
+ $string = $this->getRandomGenerator()->string($length - 2, TRUE, [$this, 'randomStringValidate']);
+ return substr_replace($string, '>&', $replacement_pos, 0);
+ }
+
+ /**
+ * Callback for random string validation.
+ *
+ * @see \Drupal\Component\Utility\Random::string()
+ *
+ * @param string $string
+ * The random string to validate.
+ *
+ * @return bool
+ * TRUE if the random string is valid, FALSE if not.
+ */
+ public function randomStringValidate($string) {
+ // Consecutive spaces causes issues for
+ // \Drupal\simpletest\WebTestBase::assertLink().
+ if (preg_match('/\s{2,}/', $string)) {
+ return FALSE;
+ }
+
+ // Starting or ending with a space means that length might not be what is
+ // expected.
+ if (preg_match('/^\s|\s$/', $string)) {
+ return FALSE;
+ }
+
+ return TRUE;
+ }
+
+ /**
+ * Generates a unique random string containing letters and numbers.
+ *
+ * Do not use this method when testing unvalidated user input. Instead, use
+ * \Drupal\simpletest\TestBase::randomString().
+ *
+ * @param int $length
+ * Length of random string to generate.
+ *
+ * @return string
+ * Randomly generated unique string.
+ *
+ * @see \Drupal\Component\Utility\Random::name()
+ */
+ protected function randomMachineName($length = 8) {
+ return $this->getRandomGenerator()->name($length, TRUE);
+ }
+
+ /**
+ * Generates a random PHP object.
+ *
+ * @param int $size
+ * The number of random keys to add to the object.
+ *
+ * @return \stdClass
+ * The generated object, with the specified number of random keys. Each key
+ * has a random string value.
+ *
+ * @see \Drupal\Component\Utility\Random::object()
+ */
+ public function randomObject($size = 4) {
+ return $this->getRandomGenerator()->object($size);
+ }
+
+ /**
+ * Gets the random generator for the utility methods.
+ *
+ * @return \Drupal\Component\Utility\Random
+ * The random generator.
+ */
+ protected function getRandomGenerator() {
+ if (!is_object($this->randomGenerator)) {
+ $this->randomGenerator = new Random();
+ }
+ return $this->randomGenerator;
+ }
+
+}