Forward instance_id from local config when reseting config during tests. (#15445)

1 files changed, 10 insertions, 1 deletions

diff --git a/tests/PHPUnit/Framework/Mock/TestConfig.php b/tests/PHPUnit/Framework/Mock/TestConfig.php
index 027499aae5..06e836c864 100644
--- a/tests/PHPUnit/Framework/Mock/TestConfig.php
+++ b/tests/PHPUnit/Framework/Mock/TestConfig.php
@@ -58,9 +58,18 @@ class TestConfig extends Config
 
         // Ensure local mods do not affect tests
         if (empty($pathGlobal)) {
+            $general = $chain->getFrom($this->getLocalPath(), 'General');
+            $instanceId = isset($general['instance_id']) ? $general['instance_id'] : null;
+
             $chain->set('Debug', $chain->getFrom($this->getGlobalPath(), 'Debug'));
             $chain->set('mail', $chain->getFrom($this->getGlobalPath(), 'mail'));
-            $chain->set('General', $chain->getFrom($this->getGlobalPath(), 'General'));
+
+            $globalGeneral = $chain->getFrom($this->getGlobalPath(), 'General');
+            if ($instanceId) {
+                $globalGeneral['instance_id'] = $instanceId;
+            }
+            $chain->set('General', $globalGeneral);
+
             $chain->set('Segments', $chain->getFrom($this->getGlobalPath(), 'Segments'));
             $chain->set('Tracker', $chain->getFrom($this->getGlobalPath(), 'Tracker'));
             $chain->set('Deletelogs', $chain->getFrom($this->getGlobalPath(), 'Deletelogs'));