diff --git a/test/plantuml-preview-test.el b/test/plantuml-preview-test.el
index 8dd9f44..ffc5820 100644
--- a/test/plantuml-preview-test.el
+++ b/test/plantuml-preview-test.el
@@ -10,8 +10,9 @@
 
 (defun assert-preview (puml output)
   (plantuml-preview-string 42 (read-test-file puml))
-  (sleep-for 2)
-  (should (equal (read-test-file output) (read-preview-buffer))))
+  (sleep-for 3)
+  (should (equal (replace-regexp-in-string " " "~" (read-test-file output))
+                 (replace-regexp-in-string " " "~" (read-preview-buffer)))))
 
 (ert-deftest preview-test ()
   (setq-local plantuml-jar-path plantuml-test-jar-path)
diff --git a/test/resources/unicode.txt b/test/resources/unicode.txt
index f6c945e..5e5ddca 100644
--- a/test/resources/unicode.txt
+++ b/test/resources/unicode.txt
@@ -1,9 +1,8 @@
      ┌────┐          ┌───┐
      │lang│          │日本語│
      └─┬──┘          └─┬─┘
-       │               │
-       │ ─────────────>│
+       │               │  
+       │ ─────────────>│  
      ┌─┴──┐          ┌─┴─┐
      │lang│          │日本語│
      └────┘          └───┘
-