#50 use UTF-8 in `start-process`; test against a txt file generated by PlantUML instead of a hand-made one

plantuml-mode.el

@@ -222,7 +222,7 @@ default output type for new buffers."
                   plantuml-java-command
                   ,@plantuml-java-args
                   (expand-file-name plantuml-jar-path)
-                  (plantuml-output-type-opt) "-p"))
+                  (plantuml-output-type-opt) "-charset" "UTF-8" "-p"))
 
 (defun plantuml-preview-string (prefix string)
   "Preview diagram from PlantUML sources (as STRING), using prefix (as PREFIX)

test/resources/unicode.txt

@@ -0,0 +1,9 @@
+     ┌────┐          ┌───┐
+     │lang│          │日本語│
+     └─┬──┘          └─┬─┘
+       │               │
+       │ ─────────────>│
+     ┌─┴──┐          ┌─┴─┐
+     │lang│          │日本語│
+     └────┘          └───┘
+