Add sys_get_temp_dir() to open_basedir tests.

tests/phpunit/tests/admin/wpAutomaticUpdater.php

@@ -609,8 +609,17 @@ public function test_is_allowed_dir_should_return_true_if_open_basedir_is_set_an
  $abspath_grandparent = trailingslashit( dirname( $abspath_parent ) );
 
  $open_basedir_backup = ini_get( 'open_basedir' );
+
+ /*
+ * Windows must use a semi-colon as a separator.
+ * For all other operating systems, a colon should be used.
+ *
+ * See https://www.php.net/manual/en/ini.core.php#ini.open-basedir
+ */
+ $separator = 'WIN' === strtoupper( substr( PHP_OS, 0, 3 ) ) ? ';' : ':';
+
  // Allow access to the directory one level above the repository.
- ini_set( 'open_basedir', wp_normalize_path( $abspath_grandparent ) );
+ ini_set( 'open_basedir', sys_get_temp_dir() . $separator . wp_normalize_path( $abspath_grandparent ) );
 
  // Checking an allowed directory should succeed.
  $actual = self::$updater->is_allowed_dir( wp_normalize_path( ABSPATH ) );
@@ -644,8 +653,17 @@ public function test_is_allowed_dir_should_return_false_if_open_basedir_is_set_a
  $abspath_grandparent = trailingslashit( dirname( $abspath_parent ) );
 
  $open_basedir_backup = ini_get( 'open_basedir' );
+
+ /*
+ * Windows must use a semi-colon as a separator.
+ * For all other operating systems, a colon should be used.
+ *
+ * See https://www.php.net/manual/en/ini.core.php#ini.open-basedir
+ */
+ $separator = 'WIN' === strtoupper( substr( PHP_OS, 0, 3 ) ) ? ';' : ':';
+
  // Allow access to the directory one level above the repository.
- ini_set( 'open_basedir', wp_normalize_path( $abspath_grandparent ) );
+ ini_set( 'open_basedir', sys_get_temp_dir() . $separator . wp_normalize_path( $abspath_grandparent ) );
 
  // Checking a directory not within the allowed path should trigger an `open_basedir` warning.
  $actual = self::$updater->is_allowed_dir( '/.git' );