diff --git a/tests/FpmRuntime/fixtures/php-fpm.conf b/tests/FpmRuntime/fixtures/php-fpm.conf
index 9c4420d63..2c286340a 100644
--- a/tests/FpmRuntime/fixtures/php-fpm.conf
+++ b/tests/FpmRuntime/fixtures/php-fpm.conf
@@ -13,6 +13,10 @@ pm.max_children = 1
 listen = /tmp/.bref/php-fpm.sock
 ; Enabled for tests
 clear_env = yes
+; The Bref layers enable this, and the tests assert on the X-Powered-By header it
+; produces. Distribution php.ini files disable it, so set it here rather than rely
+; on the host's configuration.
+php_admin_value[expose_php] = On
 ; Forward stderr of PHP processes to stderr of PHP-FPM (so that it can be sent to cloudwatch)
 catch_workers_output = yes
 ; New PHP 7.3 option that disables a verbose log prefix