diff --git a/tests/Composer/Test/InstallerTest.php b/tests/Composer/Test/InstallerTest.php
index ee306a818..9983b8c47 100644
--- a/tests/Composer/Test/InstallerTest.php
+++ b/tests/Composer/Test/InstallerTest.php
@@ -290,6 +290,7 @@ class InstallerTest extends TestCase
                                 continue;
                             }
 
+                            // Change paths like file://foobar to file:///path/to/fixtures
                             if (preg_match('{^file://[^/]}', $repo['url'])) {
                                 $repo['url'] = "file://${fixturesDir}/" . substr($repo['url'], 7);
                             }