diff --git a/tests/bootstrap.php b/tests/bootstrap.php
index e85712d6b03e454a7e356f656790cb139eb6f5a6..92d5d924987a2e62bcf50c3ca96be2060541868f 100644
--- a/tests/bootstrap.php
+++ b/tests/bootstrap.php
@@ -20,6 +20,14 @@ defined('LOCAL_OVERRIDE_DIR')
 
 chdir(APPLICATION_PATH);
 
+// Ensure vendor/ is on include_path; some PEAR components may not load correctly
+// otherwise (i.e. File_MARC may cause a "Cannot redeclare class" error by pulling
+// from the shared PEAR directory instead of the local copy):
+$pathParts = array();
+$pathParts[] = APPLICATION_PATH . '/vendor';
+$pathParts[] = get_include_path();
+set_include_path(implode(PATH_SEPARATOR, $pathParts));
+
 // Composer autoloading
 if (file_exists('vendor/autoload.php')) {
     $loader = include 'vendor/autoload.php';