Improve Python triple-quote pairing tests for electric-pair-mode

These tests were once passing incorrectly, i.e. the auto-pairing
functionality they purport to guard wasn't really working.  Added a
new test in hopes that regressions can be spotted in the future for
the now-working functionality of Python triple-quote auto-pairing via
electric-pair-mode.

bug#49518

* test/lisp/progmodes/python-tests.el
(python-triple-double-quote-pairing): Rename from
python-triple-quote-pairing.
(python-triple-single-quote-pairing): New test.

lisp/elec-pair.el

@@ -485,6 +485,27 @@ happened."
     (electric-pair-conservative-inhibit char)))
 
 (defun electric-pair-post-self-insert-function ()
+  "Member of `post-self-insert-hook'.  Do main work for `electric-pair-mode'.
+If the newly inserted character C has delimiter syntax, this
+function may decide to insert additional paired delimiters, or
+skip the insertion of the new character altogether by jumping
+over an existing identical character, or do nothing.
+
+The decision is taken by order of preference:
+
+* According to `use-region-p'.  If this returns non-nil this
+  function will unconditionally \"wrap\" the region in the
+  corresponding delimiter for C;
+
+* According to C alone, by looking C up in the tables
+  `electric-pair-paris' or `electric-pair-text-pairs' (which
+  see);
+
+* According to C's syntax and the syntactic state of the buffer
+  (both as defined by the major mode's syntax table).  This is
+  done by looking up up the variables
+  `electric-pair-inhibit-predicate', `electric-pair-skip-self'
+  and `electric-pair-skip-whitespace' (which see)."
   (let* ((pos (and electric-pair-mode (electric--after-char-pos)))
          (skip-whitespace-info))
     (pcase (electric-pair-syntax-info last-command-event)
@@ -551,18 +572,21 @@ happened."
                          (goto-char pos)
                          (funcall electric-pair-inhibit-predicate
                                   last-command-event)))))
-         (save-excursion (electric-pair--insert pair)))))
-      (_
-       (when (and (if (functionp electric-pair-open-newline-between-pairs)
-                      (funcall electric-pair-open-newline-between-pairs)
-                    electric-pair-open-newline-between-pairs)
-                  (eq last-command-event ?\n)
-                  (< (1+ (point-min)) (point) (point-max))
-                  (eq (save-excursion
-                        (skip-chars-backward "\t\s")
-                        (char-before (1- (point))))
-                      (matching-paren (char-after))))
-         (save-excursion (newline 1 t)))))))
+         (save-excursion (electric-pair--insert pair))))))))
+
+(defun electric-pair-open-newline-between-pairs-psif ()
+  "Honour `electric-pair-open-newline-between-pairs'.
+Member of `post-self-insert-hook' if `electric-pair-mode' is on."
+  (when (and (if (functionp electric-pair-open-newline-between-pairs)
+                 (funcall electric-pair-open-newline-between-pairs)
+               electric-pair-open-newline-between-pairs)
+             (eq last-command-event ?\n)
+             (< (1+ (point-min)) (point) (point-max))
+             (eq (save-excursion
+                   (skip-chars-backward "\t\s")
+                   (char-before (1- (point))))
+                 (matching-paren (char-after))))
+    (save-excursion (newline 1 t))))
 
 (defun electric-pair-will-use-region ()
   (and (use-region-p)
@@ -623,10 +647,15 @@ To toggle the mode in a single buffer, use `electric-pair-local-mode'."
                   ;; `electric-indent-mode' are used together.
                   ;; Use `vc-region-history' on these lines for more info.
                   50)
+        (add-hook 'post-self-insert-hook
+		  #'electric-pair-open-newline-between-pairs-psif
+                  50)
 	(add-hook 'self-insert-uses-region-functions
 		  #'electric-pair-will-use-region))
     (remove-hook 'post-self-insert-hook
                  #'electric-pair-post-self-insert-function)
+    (remove-hook 'post-self-insert-hook
+                 #'electric-pair-open-newline-between-pairs-psif)
     (remove-hook 'self-insert-uses-region-functions
                  #'electric-pair-will-use-region)))
 

lisp/progmodes/python.el

@@ -775,12 +775,14 @@ is used to limit the scan."
            ;; The first quote is escaped, so it's not part of a triple quote!
            (goto-char (1+ quote-starting-pos)))
           ((null string-start)
-           ;; This set of quotes delimit the start of a string.
-           (put-text-property quote-starting-pos (1+ quote-starting-pos)
+           ;; This set of quotes delimit the start of a string.  Put
+           ;; the delimiter syntax in the last of the three quotes.
+           (put-text-property (1- quote-ending-pos) quote-ending-pos
                               'syntax-table (string-to-syntax "|")))
           (t
-           ;; This set of quotes delimit the end of a string.
-           (put-text-property (1- quote-ending-pos) quote-ending-pos
+           ;; This set of quotes delimit the end of a string.  Put the
+           ;; delimiter syntax in the first of the three quotess.
+           (put-text-property quote-starting-pos (1+ quote-starting-pos)
                               'syntax-table (string-to-syntax "|"))))))
 
 (defvar python-mode-syntax-table

test/lisp/electric-tests.el

@@ -35,7 +35,8 @@
 (defun call-with-saved-electric-modes (fn)
   (let ((saved-electric (if electric-pair-mode 1 -1))
         (saved-layout (if electric-layout-mode 1 -1))
-        (saved-indent (if electric-indent-mode 1 -1)))
+        (saved-indent (if electric-indent-mode 1 -1))
+        (blink-paren-function nil))
     (electric-pair-mode -1)
     (electric-layout-mode -1)
     (electric-indent-mode -1)
@@ -173,7 +174,7 @@ The buffer's contents should %s:
           expected-string
           expected-point
           bindings
-          (modes '(quote (ruby-mode js-mode)))
+          (modes '(quote (ruby-mode js-mode python-mode)))
           (test-in-comments t)
           (test-in-strings t)
           (test-in-code t)
@@ -296,7 +297,7 @@ The buffer's contents should %s:
 ;;; Quotes
 ;;;
 (define-electric-pair-test pair-some-quotes-skip-others
-  " \"\"      " "-\"\"-----" :skip-pair-string "-ps------"
+  " \"\"      " "-\"\"\"\"---" :skip-pair-string "-ps-p----"
   :test-in-strings nil
   :bindings `((electric-pair-text-syntax-table
                . ,prog-mode-syntax-table)))

test/lisp/progmodes/python-tests.el

@@ -193,7 +193,6 @@ aliqua."
 
 (ert-deftest python-syntax-after-python-backspace ()
   ;; `python-indent-dedent-line-backspace' garbles syntax
-  :expected-result :failed
   (python-tests-with-temp-buffer
       "\"\"\""
     (goto-char (point-max))
@@ -5283,7 +5282,7 @@ urlpatterns = patterns('',
            (should (= (current-indentation) 23))))
       (or eim (electric-indent-mode -1)))))
 
-(ert-deftest python-triple-quote-pairing ()
+(ert-deftest python-triple-double-quote-pairing ()
   (let ((epm electric-pair-mode))
     (unwind-protect
         (progn
@@ -5310,6 +5309,33 @@ urlpatterns = patterns('',
                             "\"\n\"\"\"\n"))))
       (or epm (electric-pair-mode -1)))))
 
+(ert-deftest python-triple-single-quote-pairing ()
+  (let ((epm electric-pair-mode))
+    (unwind-protect
+        (progn
+          (python-tests-with-temp-buffer
+           "''\n"
+           (or epm (electric-pair-mode 1))
+           (goto-char (1- (point-max)))
+           (python-tests-self-insert ?')
+           (should (string= (buffer-string)
+                            "''''''\n"))
+           (should (= (point) 4)))
+          (python-tests-with-temp-buffer
+           "\n"
+           (python-tests-self-insert (list ?' ?' ?'))
+           (should (string= (buffer-string)
+                            "''''''\n"))
+           (should (= (point) 4)))
+          (python-tests-with-temp-buffer
+           "'\n''\n"
+           (goto-char (1- (point-max)))
+           (python-tests-self-insert ?')
+           (should (= (point) (1- (point-max))))
+           (should (string= (buffer-string)
+                            "'\n'''\n"))))
+      (or epm (electric-pair-mode -1)))))
+
 
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