Better test docs and cleanup

plantuml-mode.el

@@ -246,7 +246,9 @@ to choose where to display it:
 - else -> new window"
   (let ((b (get-buffer plantuml-preview-buffer)))
     (when b
-      (kill-buffer b)))
+      (with-current-buffer b
+	(setq buffer-read-only nil)
+	(erase-buffer))))
 
   (let* ((imagep (and (display-images-p)
                       (plantuml-is-image-output-p)))

test/plantuml-preview-test.el

@@ -9,6 +9,8 @@
 ;;; Code:
 
 (defun assert-preview (puml output &optional format)
+  "Run PlantUML on the source PUML and asserts the result to be
+equal to OUTPUT. Can choose the output FORMAT (default: utxt)."
   (if format
     (setq plantuml-output-type format)
     (setq plantuml-output-type "utxt"))
@@ -18,13 +20,19 @@
                  (replace-regexp-in-string " " "~" (read-preview-buffer)))))
 
 (ert-deftest preview-utxt-test ()
-  (setq-local plantuml-jar-path plantuml-test-jar-path)
-  (assert-preview "a-b.puml" "a-b.txt"))
+  (unwind-protect
+      (progn
+        (setq-local plantuml-jar-path plantuml-test-jar-path)
+        (assert-preview "a-b.puml" "a-b.txt"))
+    (cleanup-preview)))
 
 (ert-deftest preview-unicode-test ()
-  (setq-local plantuml-jar-path plantuml-test-jar-path)
-  (setq-local plantuml-output-type "utxt")
-  (assert-preview "unicode.puml" "unicode.txt"))
+  (unwind-protect
+      (progn
+        (setq-local plantuml-jar-path plantuml-test-jar-path)
+        (setq-local plantuml-output-type "utxt")
+        (assert-preview "unicode.puml" "unicode.txt")))
+  (cleanup-preview))
 
 (provide 'plantuml-mode-preview-test)
 

test/test-helper.el

@@ -22,17 +22,38 @@
 (defvar plantuml-test-jar-path
   (f-join package-code-path "bin/plantuml.jar"))
 
+(defun test-file-path (path)
+  "Translate the relative test path PATH in an absolute path."
+  (f-join plantuml-test-resources-path path))
+
+(defun cleanup-preview ()
+  "Kill the preview buffer"
+  (let ((proc (get-buffer-process plantuml-preview-buffer)))
+    (when proc
+      (set-process-query-on-exit-flag proc nil))
+    (kill-buffer plantuml-preview-buffer)))
+
 (defun read-buffer (bufname)
+  "Read the contents of buffer BUFNAME."
   (with-current-buffer (get-buffer bufname)
     (buffer-string)))
 
 (defun read-preview-buffer ()
+  "Read the contents of the PlantUML preview buffer."
   (read-buffer plantuml-preview-buffer))
 
 (defun read-test-file (path)
-  (f-read (f-join plantuml-test-resources-path path) 'utf-8))
+  "Fetch the string content of the test file at relative path PATH."
+  (f-read (test-file-path path) 'utf-8))
+
+(defun open-test-file-in-buf (test-file)
+  "Visit TEST-FILE in a new buffer."
+  (message "buffer list before: %s" (buffer-list))
+  (find-file (test-file-path test-file))
+  (message "buffer list after: %s" (buffer-list)))
 
 (defun load-plantuml-mode ()
+  "Load the plantuml-mode package."
   (require 'plantuml-mode (f-expand "plantuml-mode.el" package-code-path)))
 
 (load-plantuml-mode)