diff --git a/core/includes/bootstrap.inc b/core/includes/bootstrap.inc
index adc2923..53f5229 100644
--- a/core/includes/bootstrap.inc
+++ b/core/includes/bootstrap.inc
@@ -628,9 +628,9 @@ function drupal_valid_test_ua($new_prefix = NULL) {
   // string.
   $http_user_agent = isset($_SERVER['HTTP_USER_AGENT']) ? $_SERVER['HTTP_USER_AGENT'] : NULL;
   $user_agent = isset($_COOKIE['SIMPLETEST_USER_AGENT']) ? $_COOKIE['SIMPLETEST_USER_AGENT'] : $http_user_agent;
-  if (isset($user_agent) && preg_match("/^(simpletest\d+);(.+);(.+);(.+)$/", $user_agent, $matches)) {
+  if (isset($user_agent) && preg_match("/^(simpletest\d+):(.+):(.+):(.+)$/", $user_agent, $matches)) {
     list(, $prefix, $time, $salt, $hmac) = $matches;
-    $check_string =  $prefix . ';' . $time . ';' . $salt;
+    $check_string =  $prefix . ':' . $time . ':' . $salt;
     // Read the hash salt prepared by drupal_generate_test_ua().
     // This function is called before settings.php is read and Drupal's error
     // handlers are set up. While Drupal's error handling may be properly
@@ -687,8 +687,8 @@ function drupal_generate_test_ua($prefix) {
   }
   // Generate a moderately secure HMAC based on the database credentials.
   $salt = uniqid('', TRUE);
-  $check_string = $prefix . ';' . time() . ';' . $salt;
-  return $check_string . ';' . Crypt::hmacBase64($check_string, $key);
+  $check_string = $prefix . ':' . time() . ':' . $salt;
+  return $check_string . ':' . Crypt::hmacBase64($check_string, $key);
 }
 
 /**
diff --git a/core/tests/README.md b/core/tests/README.md
new file mode 100644
index 0000000..df091f3
--- /dev/null
+++ b/core/tests/README.md
@@ -0,0 +1,14 @@
+# Running tests
+
+## Function tests
+
+* Start phantomjs:
+```
+phantomjs --ssl-protocol=any --ignore-ssl-errors=true vendor/jcalderonzumba/gastonjs/src/Client/main.js 8510 1024 768 2>&1 >> /dev/null &
+```
+* Run the function tests:
+```
+export SIMPLETEST_DB='mysql://root@localhost/dev_d8'
+export SIMPLETEST_BASE_URL='http://d8.dev'
+vendor/bin/phpunit -c core core/modules/simpletest/tests/src/Functional/BrowserTestBaseTest.php
+```