diff --git a/samples/cachingfs/caching_fs_test.go b/samples/cachingfs/caching_fs_test.go
index ee78f43..48e0e70 100644
--- a/samples/cachingfs/caching_fs_test.go
+++ b/samples/cachingfs/caching_fs_test.go
@@ -63,6 +63,11 @@ func (t *CachingFSTest) setUp(
 }
 
 func (t *CachingFSTest) TearDown() {
+	// Was the file system mounted?
+	if t.mfs == nil {
+		return
+	}
+
 	// Unmount the file system. Try again on "resource busy" errors.
 	delay := 10 * time.Millisecond
 	for {