2013-03-22: added a test for emacs customization.

added a test for emacs customization.

diff --git a/tests/emacs-customization-tex-master.w b/tests/emacs-customization-tex-master.w
new file mode 100644
--- /dev/null
+++ b/tests/emacs-customization-tex-master.w
@@ -0,0 +1,33 @@
+defun guess-TeX-master : filename
+      . "Guess the master file for FILENAME from currently open .tex files."
+      let 
+          : 
+            candidate nil
+            filename : file-name-nondirectory filename
+          save-excursion
+            dolist : buffer : buffer-list
+              with-current-buffer buffer
+
+                let 
+                   : 
+                     name : buffer-name
+                     file buffer-file-name
+                   if 
+                     and file : string-match "\\.tex$" file
+
+                     progn
+                       goto-char : point-min
+                       if 
+                          re-search-forward 
+                            concat "\\\\input{" filename "}"
+                            . nil t
+                          setq candidate file
+                       if 
+                          re-search-forward 
+                            concat "\\\\include{" (file-name-sans-extension filename) "}"
+                            . nil t
+                          setq candidate file
+          
+          if candidate
+            message "TeX master document: %s" : file-name-nondirectory candidate
+          . candidate