master 112cb75141: test: Remove redundant "" arg to `mapconcat`

[Stefan Monnier]

branch: master
commit 112cb751419e4830a036ecabd6a799feb5977455
Author: Stefan Monnier <monnier@iro.umontreal.ca>
Commit: Stefan Monnier <monnier@iro.umontreal.ca>

    test: Remove redundant "" arg to `mapconcat`
    
    * test/src/process-tests.el (process-test-stderr-filter):
    * test/src/print-tests.el (print-tests-continuous-numbering):
    * test/src/fns-tests.el (fns-tests-mapconcat):
    * test/src/data-tests.el (test-bool-vector-to-hex-string):
    * test/src/casefiddle-tests.el (casefiddle-tests-char-properties)
    (casefiddle-tests-case-table, casefiddle-tests-casing-character):
    * test/lisp/tabify-tests.el (tabify-tests--test-changes):
    * test/lisp/subr-tests.el (subr-tests-bug22027):
    * test/lisp/sort-tests.el (sort-tests-random-word):
    * test/lisp/net/hmac-md5-tests.el (hmac-md5-test-encode-string):
    * test/lisp/md4-tests.el (md4-tests-digest->hex):
    * test/lisp/emacs-lisp/cl-extra-tests.el (cl-extra-test-map):
    * test/lisp/dired-tests.el (dired-test-directory-files):
    * test/lisp/char-fold-tests.el (char-fold--random-word):
    * test/lisp/ansi-color-tests.el (ansi-color-incomplete-sequences-test):
    Remove redundant "" arg to `mapconcat`.
---
 test/lisp/ansi-color-tests.el          | 4 ++--
 test/lisp/char-fold-tests.el           | 2 +-
 test/lisp/dired-tests.el               | 4 ++--
 test/lisp/emacs-lisp/cl-extra-tests.el | 2 +-
 test/lisp/md4-tests.el                 | 2 +-
 test/lisp/net/hmac-md5-tests.el        | 2 +-
 test/lisp/sort-tests.el                | 2 +-
 test/lisp/subr-tests.el                | 2 +-
 test/lisp/tabify-tests.el              | 4 ++--
 test/src/casefiddle-tests.el           | 6 +++---
 test/src/data-tests.el                 | 3 +--
 test/src/fns-tests.el                  | 4 ++--
 test/src/print-tests.el                | 6 ++++--
 test/src/process-tests.el              | 4 ++--
 14 files changed, 24 insertions(+), 23 deletions(-)

diff --git a/test/lisp/ansi-color-tests.el b/test/lisp/ansi-color-tests.el
index 1b04e8e9de..f672f33491 100644
--- a/test/lisp/ansi-color-tests.el
+++ b/test/lisp/ansi-color-tests.el
@@ -135,7 +135,7 @@ strings with `eq', this function compares them with 
`equal'."
     (with-temp-buffer
       (should (equal-including-properties
                filtered-str
-               (mapconcat ansi-filt strs ""))))
+               (mapconcat ansi-filt strs))))
 
     ;; Tests for `ansi-color-filter-region'
     (with-temp-buffer
@@ -156,7 +156,7 @@ strings with `eq', this function compares them with 
`equal'."
     (with-temp-buffer
       (should (ansi-color-tests-equal-props
                propertized-str
-               (mapconcat ansi-app strs ""))))
+               (mapconcat ansi-app strs))))
 
     ;; Tests for `ansi-color-apply-on-region'
     (with-temp-buffer
diff --git a/test/lisp/char-fold-tests.el b/test/lisp/char-fold-tests.el
index 749ec0a8d3..e7f5ff6fd2 100644
--- a/test/lisp/char-fold-tests.el
+++ b/test/lisp/char-fold-tests.el
@@ -26,7 +26,7 @@
 
 (defun char-fold--random-word (n)
   (mapconcat (lambda (_) (string (+ 9 (random 117))))
-             (make-list n nil) ""))
+             (make-list n nil)))
 
 (defun char-fold--ascii-upcase (string)
   "Like `upcase' but acts on ASCII characters only."
diff --git a/test/lisp/dired-tests.el b/test/lisp/dired-tests.el
index 9cf0151905..09becc7fe7 100644
--- a/test/lisp/dired-tests.el
+++ b/test/lisp/dired-tests.el
@@ -456,8 +456,8 @@
             (dolist (file '(a b c d))
               (make-empty-file (expand-file-name (symbol-name file) testdir)))
             (should (= 6 (length (directory-files testdir))))
-            (should (equal "abcd" (mapconcat 'identity (directory-files
-                                                        testdir nil nod) "")))
+            (should (equal "abcd" (mapconcat #'identity (directory-files
+                                                         testdir nil nod))))
             (should (= 2 (length (directory-files testdir nil "[bc]"))))
             (should (= 3 (length (directory-files testdir nil nod nil 3))))
             (dolist (file '(5 4 3 2 1))
diff --git a/test/lisp/emacs-lisp/cl-extra-tests.el 
b/test/lisp/emacs-lisp/cl-extra-tests.el
index 801885c0d4..297e413d85 100644
--- a/test/lisp/emacs-lisp/cl-extra-tests.el
+++ b/test/lisp/emacs-lisp/cl-extra-tests.el
@@ -77,7 +77,7 @@
         (fn3 (lambda (x _y _z) (string-to-char (format "%S" x)))))
     (should (equal lst (cl-map 'list fn1 lst)))
     (should (equal (vconcat lst2) (cl-map 'vector fn2 lst lst2)))
-    (should (equal (mapconcat (lambda (x) (format "%S" x)) lst "")
+    (should (equal (mapconcat (lambda (x) (format "%S" x)) lst)
                    (cl-map 'string fn3 lst lst2 lst3)))))
 
 (ert-deftest cl-extra-test-maplist ()
diff --git a/test/lisp/md4-tests.el b/test/lisp/md4-tests.el
index fb7df652bc..d1f227cb90 100644
--- a/test/lisp/md4-tests.el
+++ b/test/lisp/md4-tests.el
@@ -29,7 +29,7 @@
 
 (defun md4-tests-digest->hex (str)
   "Print digest STR in hexadecimal."
-  (mapconcat (lambda (x) (format "%02x" x)) str ""))
+  (mapconcat (lambda (x) (format "%02x" x)) str))
 
 (ert-deftest md4-test-rfc1320 ()
   "Verify the test suite results in RFC 1320.
diff --git a/test/lisp/net/hmac-md5-tests.el b/test/lisp/net/hmac-md5-tests.el
index ce08dd89d1..09bbb8015e 100644
--- a/test/lisp/net/hmac-md5-tests.el
+++ b/test/lisp/net/hmac-md5-tests.el
@@ -48,7 +48,7 @@
   (should (equal (encode-hex-string
                   (hmac-md5 (decode-hex-string
                              (mapconcat (lambda (c) (concat (list c) "d"))
-                                        (make-string 50 ?c) ""))
+                                        (make-string 50 ?c)))
                             (decode-hex-string 
"0102030405060708090a0b0c0d0e0f10111213141516171819")))
                  "697eaf0aca3a3aea3a75164746ffaa79"))
 
diff --git a/test/lisp/sort-tests.el b/test/lisp/sort-tests.el
index 7f49cc38d1..d8d42452ec 100644
--- a/test/lisp/sort-tests.el
+++ b/test/lisp/sort-tests.el
@@ -28,7 +28,7 @@
   (mapconcat (lambda (_) (string (let ((c (random 52)))
                               (+ (if (> c 25) 71 65)
                                  c))))
-             (make-list n nil) ""))
+             (make-list n nil)))
 
 (defun sort-tests--insert-words-sort-and-compare (words separator function 
reverse less-predicate)
   (with-temp-buffer
diff --git a/test/lisp/subr-tests.el b/test/lisp/subr-tests.el
index 3d03057f56..4310b7291a 100644
--- a/test/lisp/subr-tests.el
+++ b/test/lisp/subr-tests.el
@@ -635,7 +635,7 @@ cf. Bug#25477."
   (let ((default "foo") res)
     (cl-letf (((symbol-function 'read-string)
                (lambda (_prompt &optional _init _hist def _inher-input) def)))
-      (setq res (read-passwd "pass: " 'confirm (mapconcat #'string default 
"")))
+      (setq res (read-passwd "pass: " 'confirm (mapconcat #'string default)))
       (should (string= default res)))))
 
 (ert-deftest subr-tests--gensym ()
diff --git a/test/lisp/tabify-tests.el b/test/lisp/tabify-tests.el
index eaa3527df0..1c8940c30f 100644
--- a/test/lisp/tabify-tests.el
+++ b/test/lisp/tabify-tests.el
@@ -27,9 +27,9 @@
 (defun tabify-tests--test-changes (fun changes width)
   (with-temp-buffer
     (let ((tab-width width))
-      (insert (mapconcat #'car changes ""))
+      (insert (mapconcat #'car changes))
       (funcall fun (point-min) (point-max))
-      (should (equal (buffer-string) (mapconcat #'cadr changes ""))))))
+      (should (equal (buffer-string) (mapconcat #'cadr changes))))))
 
 (ert-deftest tabify-tests-untabify ()
   (let ((changes '(("***\n"        "***\n")
diff --git a/test/src/casefiddle-tests.el b/test/src/casefiddle-tests.el
index eb096f2112..652af41729 100644
--- a/test/src/casefiddle-tests.el
+++ b/test/src/casefiddle-tests.el
@@ -57,7 +57,7 @@
                     errors)))
           (setq expected (cdr expected)))))
     (when errors
-      (ert-fail (mapconcat (lambda (line) line) (nreverse errors) "")))))
+      (ert-fail (mapconcat #'identity (nreverse errors))))))
 
 
 (defconst casefiddle-tests--characters
@@ -98,7 +98,7 @@
                      errors)))
            (setq props (cdr props) tabs (cdr tabs) expected (cdr expected)))))
      (when errors
-       (mapconcat (lambda (line) line) (nreverse errors) "")))))
+       (mapconcat #'identity (nreverse errors))))))
 
 
 (ert-deftest casefiddle-tests-casing-character ()
@@ -116,7 +116,7 @@
                      errors)))
            (setq funcs (cdr funcs) expected (cdr expected)))))
      (when errors
-       (mapconcat (lambda (line) line) (nreverse errors) "")))))
+       (mapconcat (lambda (line) line) (nreverse errors))))))
 
 
 (ert-deftest casefiddle-tests-casing-word ()
diff --git a/test/src/data-tests.el b/test/src/data-tests.el
index 0f84b2fb77..463a894d09 100644
--- a/test/src/data-tests.el
+++ b/test/src/data-tests.el
@@ -200,8 +200,7 @@ this is exactly representable and is greater than
             nibbles)
       (setf v (nthcdr 4 v)))
     (mapconcat (lambda (n) (format "%X" n))
-               (nreverse nibbles)
-               "")))
+               (nreverse nibbles))))
 
 (defun test-bool-vector-count-consecutive-tc (desc)
   "Run a test case for `bool-vector-count-consecutive'.
diff --git a/test/src/fns-tests.el b/test/src/fns-tests.el
index 4ef428af03..fe8df7097a 100644
--- a/test/src/fns-tests.el
+++ b/test/src/fns-tests.el
@@ -614,9 +614,9 @@
   (should (string= (mapconcat #'identity '("Ä" "ø" "☭" "தமிழ்") "_漢字_")
                    "Ä_漢字_ø_漢字_☭_漢字_தமிழ்"))
   ;; vector
-  (should (string= (mapconcat #'identity ["a" "b"] "") "ab"))
+  (should (string= (mapconcat #'identity ["a" "b"]) "ab"))
   ;; bool-vector
-  (should (string= (mapconcat #'identity [nil nil] "") ""))
+  (should (string= (mapconcat #'identity [nil nil]) ""))
   (should-error (mapconcat #'identity [nil nil t])
                 :type 'wrong-type-argument))
 
diff --git a/test/src/print-tests.el b/test/src/print-tests.el
index 5c349342eb..faab196f22 100644
--- a/test/src/print-tests.el
+++ b/test/src/print-tests.el
@@ -190,7 +190,8 @@ otherwise, use a different charset."
   "Printing observes `print-continuous-numbering'."
   ;; cl-print does not support print-continuous-numbering.
   :expected-result (if (eq (symbol-function #'print-tests--prin1-to-string)
-                           #'cl-prin1-to-string) :failed :passed)
+                           #'cl-prin1-to-string)
+                       :failed :passed)
   (let* ((x (list 1))
          (y "hello")
          (g (gensym))
@@ -201,7 +202,8 @@ otherwise, use a different charset."
           (print-number-table nil))
       (should (string-match
                "(#1=(1) #1# #2=\"hello\" #2#)(#3=#:g[[:digit:]]+ #3#)(#1# #2# 
#3#)#2#$"
-               (mapconcat #'print-tests--prin1-to-string `((,x ,x ,y ,y) (,g 
,g) (,x ,y ,g) ,y) ""))))
+               (mapconcat #'print-tests--prin1-to-string
+                          `((,x ,x ,y ,y) (,g ,g) (,x ,y ,g) ,y)))))
 
     ;; This is the special case for byte-compile-output-docform
     ;; mentioned in a comment in print_preprocess.  When
diff --git a/test/src/process-tests.el b/test/src/process-tests.el
index 6e1e148332..7d3d9eb72b 100644
--- a/test/src/process-tests.el
+++ b/test/src/process-tests.el
@@ -134,12 +134,12 @@ process to complete."
     (should (equal 1 (with-current-buffer stdout-buffer
                       (point-max))))
     (should (equal "hello stdout!\n"
-                  (mapconcat #'identity (nreverse stdout-output) "")))
+                  (mapconcat #'identity (nreverse stdout-output))))
     (should stderr-sentinel-called)
     (should (equal 1 (with-current-buffer stderr-buffer
                       (point-max))))
     (should (equal "hello stderr!\n"
-                  (mapconcat #'identity (nreverse stderr-output) ""))))))
+                  (mapconcat #'identity (nreverse stderr-output)))))))
 
 (ert-deftest set-process-filter-t ()
   "Test setting process filter to t and back." ;; Bug#36591