diff --git a/PHPCI/Plugin/PhpUnit.php b/PHPCI/Plugin/PhpUnit.php
index 70e0e74f..fc597f2d 100644
--- a/PHPCI/Plugin/PhpUnit.php
+++ b/PHPCI/Plugin/PhpUnit.php
@@ -133,7 +133,7 @@ class PhpUnit implements PHPCI\Plugin, PHPCI\ZeroConfigPlugin
         }
 
         if (isset($options['coverage'])) {
-            $this->coverage = " --coverage-html {$options['coverage']} ";
+            $this->coverage = ' --coverage-html ' . $this->phpci->interpolate($options['coverage']) . ' ';
         }
     }