1 files changed, 59 insertions, 5 deletions
diff --git a/test/src/coding-tests.el b/test/src/coding-tests.el
index 4008b510223..0bdcff22ce5 100644
--- a/test/src/coding-tests.el
+++ b/test/src/coding-tests.el
@@ -1,4 +1,4 @@
-;;; coding-tests.el --- tests for text encoding and decoding
+;;; coding-tests.el --- tests for text encoding and decoding -*- lexical-binding: t -*-
 
 ;; Copyright (C) 2013-2021 Free Software Foundation, Inc.
 
@@ -296,7 +296,7 @@
 ;;; decoder, not for regression testing.
 
 (defun generate-ascii-file ()
-  (dotimes (i 100000)
+  (dotimes (_i 100000)
     (insert-char ?a 80)
     (insert "\n")))
 
@@ -309,13 +309,13 @@
     (insert "\n")))
 
 (defun generate-mostly-nonascii-file ()
-  (dotimes (i 30000)
+  (dotimes (_i 30000)
     (insert-char ?a 80)
     (insert "\n"))
-  (dotimes (i 20000)
+  (dotimes (_i 20000)
     (insert-char ?À 80)
     (insert "\n"))
-  (dotimes (i 10000)
+  (dotimes (_i 10000)
     (insert-char ?あ 80)
     (insert "\n")))
 
@@ -375,6 +375,60 @@
 			 (with-temp-buffer (insert-file-contents (car file))))))
 	  (insert (format "%s: %s\n" (car file) result)))))))
 
+(ert-deftest coding-nocopy-trivial ()
+  "Check that the NOCOPY parameter works for the trivial coding system."
+  (let ((s "abc"))
+    (should-not (eq (decode-coding-string s nil nil) s))
+    (should (eq (decode-coding-string s nil t) s))
+    (should-not (eq (encode-coding-string s nil nil) s))
+    (should (eq (encode-coding-string s nil t) s))))
+
+(ert-deftest coding-nocopy-ascii ()
+  "Check that the NOCOPY parameter works for ASCII-only strings."
+  (let* ((uni (apply #'string (number-sequence 0 127)))
+         (multi (string-to-multibyte uni)))
+    (dolist (s (list uni multi))
+      ;; Encodings without EOL conversion.
+      (dolist (coding '(us-ascii-unix iso-latin-1-unix utf-8-unix))
+        (should-not (eq (decode-coding-string s coding nil) s))
+        (should-not (eq (encode-coding-string s coding nil) s))
+        (should (eq (decode-coding-string s coding t) s))
+        (should (eq (encode-coding-string s coding t) s))
+        (should (eq last-coding-system-used coding)))
+
+      ;; With EOL conversion inhibited.
+      (let ((inhibit-eol-conversion t))
+        (dolist (coding '(us-ascii iso-latin-1 utf-8))
+          (should-not (eq (decode-coding-string s coding nil) s))
+          (should-not (eq (encode-coding-string s coding nil) s))
+          (should (eq (decode-coding-string s coding t) s))
+          (should (eq (encode-coding-string s coding t) s))))))
+
+  ;; Check identity decoding with EOL conversion for ASCII except CR.
+  (let* ((uni (apply #'string (delq ?\r (number-sequence 0 127))))
+         (multi (string-to-multibyte uni)))
+    (dolist (s (list uni multi))
+      (dolist (coding '(us-ascii-dos iso-latin-1-dos utf-8-dos mac-roman-mac))
+        (should-not (eq (decode-coding-string s coding nil) s))
+        (should (eq (decode-coding-string s coding t) s)))))
+
+  ;; Check identity encoding with EOL conversion for ASCII except LF.
+  (let* ((uni (apply #'string (delq ?\n (number-sequence 0 127))))
+         (multi (string-to-multibyte uni)))
+    (dolist (s (list uni multi))
+      (dolist (coding '(us-ascii-dos iso-latin-1-dos utf-8-dos mac-roman-mac))
+        (should-not (eq (encode-coding-string s coding nil) s))
+        (should (eq (encode-coding-string s coding t) s))))))
+
+
+(ert-deftest coding-check-coding-systems-region ()
+  (should (equal (check-coding-systems-region "aå" nil '(utf-8))
+                 nil))
+  (should (equal (check-coding-systems-region "aåbγc" nil
+                                              '(utf-8 iso-latin-1 us-ascii))
+                 '((iso-latin-1 3) (us-ascii 1 3))))
+  (should-error (check-coding-systems-region "å" nil '(bad-coding-system))))
+
 ;; Local Variables:
 ;; byte-compile-warnings: (not obsolete)
 ;; End: