master 849b7756fd: Improve manual display tests of undisplayable chars (bug#58168)

[Mattias Engdegård]

branch: master
commit 849b7756fd31a69791e67dfe010b1e10f0168c83
Author: Mattias Engdegård <mattiase@acm.org>
Commit: Mattias Engdegård <mattiase@acm.org>

    Improve manual display tests of undisplayable chars (bug#58168)
    
    Test display of multibyte raw bytes, as well as undisplayable
    multibyte chars (C1 controls and other values).
    
    The test still assumes that raw bytes should be displayed identically
    to undisplayable characters (such as C1 controls) because that is how
    the display code currently works.
    
    * test/manual/redisplay-testsuite.el (test-redisplay-5-toggle)
    (test-redisplay-5): Fix likely typo (#x3fffc) of raw byte value.
    (test-redisplay-6): New.
---
 test/manual/redisplay-testsuite.el | 35 +++++++++++++++++++++++++++--------
 1 file changed, 27 insertions(+), 8 deletions(-)

diff --git a/test/manual/redisplay-testsuite.el 
b/test/manual/redisplay-testsuite.el
index 01b0a895a4..5495146b87 100644
--- a/test/manual/redisplay-testsuite.el
+++ b/test/manual/redisplay-testsuite.el
@@ -305,7 +305,7 @@ static unsigned char x_bits[] = {0xff, 0x81, 0xbd, 0xa5, 
0xa5, 0xbd, 0x81, 0xff
   (let ((label (if display-raw-bytes-as-hex "\\x80" "\\200")))
     (overlay-put test-redisplay-5a-expected-overlay 'display
                  (propertize label 'face 'escape-glyph)))
-  (let ((label (if display-raw-bytes-as-hex "\\x3fffc" "\\777774")))
+  (let ((label (if display-raw-bytes-as-hex "\\xfc" "\\374")))
     (overlay-put test-redisplay-5b-expected-overlay 'display
                  (propertize label 'face 'escape-glyph))))
 
@@ -320,18 +320,36 @@ static unsigned char x_bits[] = {0xff, 0x81, 0xbd, 0xa5, 
0xa5, 0xbd, 0x81, 0xff
         (test-insert-overlay " " 'display "\200"))
   (insert "\n\n")
   (insert "  Expected: ")
-  ;; This tests a large codepoint, to make sure the internal buffer we
-  ;; use to produce the representation is large enough.
-  (aset printable-chars #x3fffc nil)
   (setq test-redisplay-5b-expected-overlay
         (test-insert-overlay " " 'display
-                             (propertize "\\777774" 'face 'escape-glyph)))
+                             (propertize "\\374" 'face 'escape-glyph)))
   (insert "\n    Result: ")
   (setq test-redisplay-5b-result-overlay
-        (test-insert-overlay " " 'display (char-to-string #x3fffc)))
+        (test-insert-overlay " " 'display (char-to-string #x3ffffc)))
+  (insert "\n\n")
+  (insert-button "Toggle between octal and hex display for raw bytes"
+                 'action 'test-redisplay-5-toggle)
+  (insert "\n\n"))
+
+(defun test-redisplay-6 ()
+  (insert "Test 6: Display of unprintable Unicode chars:\n\n")
+  (insert "  Expected: ")
+  (test-insert-overlay " " 'display
+                       (propertize "\\200" 'face 'escape-glyph))
+  (insert "  (representing U+0100)")
+  (insert "\n    Result: ")
+  (test-insert-overlay " " 'display "\u0080")
   (insert "\n\n")
-  (insert-button "Toggle between octal and hex display"
-                 'action 'test-redisplay-5-toggle))
+  ;; This tests a large codepoint, to make sure the internal buffer we
+  ;; use to produce the representation is large enough.
+  (insert "  Expected: ")
+  (aset printable-chars #x10abcd nil)
+  (test-insert-overlay " " 'display
+                       (propertize "\\4125715" 'face 'escape-glyph))
+  (insert "  (representing U+0010ABCD)")
+  (insert "\n    Result: ")
+  (test-insert-overlay " " 'display "\U0010ABCD")
+  (insert "\n\n"))
 
 (defun test-redisplay ()
   (interactive)
@@ -349,6 +367,7 @@ static unsigned char x_bits[] = {0xff, 0x81, 0xbd, 0xa5, 
0xa5, 0xbd, 0x81, 0xff
     (test-redisplay-3)
     (test-redisplay-4)
     (test-redisplay-5)
+    (test-redisplay-6)
     (goto-char (point-min))))
 
 ;;; redisplay-testsuite.el ends here