diff --git a/core/testMinimumPhpVersion.php b/core/testMinimumPhpVersion.php
index f67c343c9615541cfdf5b53e6228fca2321751e5..118c7204a1aa493d8bbc2ea7e07b3da8b7d983e2 100644
--- a/core/testMinimumPhpVersion.php
+++ b/core/testMinimumPhpVersion.php
@@ -77,8 +77,7 @@ if (!function_exists('Piwik_ExitWithMessage')) {
     function Piwik_ShouldPrintBackTraceWithMessage()
     {
         $bool = (defined('PIWIK_PRINT_ERROR_BACKTRACE') && PIWIK_PRINT_ERROR_BACKTRACE)
-                || !empty($GLOBALS['PIWIK_TRACKER_DEBUG'])
-                || defined('PIWIK_TEST_MODE');
+                || !empty($GLOBALS['PIWIK_TRACKER_DEBUG']);
         return $bool;
     }
 
diff --git a/tests/PHPUnit/proxy/index.php b/tests/PHPUnit/proxy/index.php
index 4494ca0e0f96bbd1bc2ce40170c168b8d18f4a07..7f5efa666fe83d31cabb4425e04eb9fec248785b 100644
--- a/tests/PHPUnit/proxy/index.php
+++ b/tests/PHPUnit/proxy/index.php
@@ -10,6 +10,9 @@ Piwik_TestingEnvironment::addHooks();
 
 if (\Piwik\DbHelper::isInstalled()) {
     \Piwik\ViewDataTable\Manager::clearAllViewDataTableParameters();
+} else {
+    // Not installed yet, display backtrace when error
+    define('PIWIK_PRINT_ERROR_BACKTRACE', true);
 }
 
 \Piwik\Profiler::setupProfilerXHProf();