Use 'eshell-with-handles' in a few more places

* lisp/eshell/em-alias.el (eshell-write-aliases-list):
* lisp/eshell/em-script.el (eshell-batch-file):
* lisp/eshell/esh-cmd.el (eshell-command-to-value):
* lisp/eshell/eshell.el (eshell-command): Use 'eshell-with-handles'.

* test/lisp/eshell/esh-io-tests.el (eshell-test-file-string): Move to...
* test/lisp/eshell/eshell-tests-helpers.el (eshell-test-file-string):
... here.

* test/lisp/eshell/eshell-tests.el
(eshell-test/eshell-command/output-file):
* test/lisp/eshell/em-script-tests.el
(em-script-test/execute-file/output-file): New tests.

4 files changed, 20 insertions, 6 deletions

diff --git a/test/lisp/eshell/em-script-tests.el b/test/lisp/eshell/em-script-tests.el
index 86a78e43026..b9f96fa86db 100644
--- a/test/lisp/eshell/em-script-tests.el
+++ b/test/lisp/eshell/em-script-tests.el
@@ -113,6 +113,14 @@
         (eshell-execute-file temp-file '(1 2 3) t))
       (should (equal (buffer-string) "6")))))
 
+(ert-deftest em-script-test/execute-file/output-file ()
+  "Test `eshell-execute-file' redirecting to a file."
+  (ert-with-temp-file temp-file :text "echo more"
+    (ert-with-temp-file output-file :text "initial"
+      (with-temp-eshell-settings
+        (eshell-execute-file temp-file nil output-file))
+      (should (equal (eshell-test-file-string output-file) "moreinitial")))))
+
 (ert-deftest em-script-test/batch-file ()
   "Test running an Eshell script file as a batch script."
   (ert-with-temp-file temp-file
diff --git a/test/lisp/eshell/esh-io-tests.el b/test/lisp/eshell/esh-io-tests.el
index b4e8c0b4a9a..6add14c05fa 100644
--- a/test/lisp/eshell/esh-io-tests.el
+++ b/test/lisp/eshell/esh-io-tests.el
@@ -34,12 +34,6 @@
 (defvar eshell-test-value-with-fun nil)
 (defun eshell-test-value-with-fun ())
 
-(defun eshell-test-file-string (file)
-  "Return the contents of FILE as a string."
-  (with-temp-buffer
-    (insert-file-contents file)
-    (buffer-string)))
-
 (defun eshell/test-output ()
   "Write some test output separately to stdout and stderr."
   (eshell-printn "stdout")
diff --git a/test/lisp/eshell/eshell-tests-helpers.el b/test/lisp/eshell/eshell-tests-helpers.el
index bfd829c95e9..def04be0577 100644
--- a/test/lisp/eshell/eshell-tests-helpers.el
+++ b/test/lisp/eshell/eshell-tests-helpers.el
@@ -139,6 +139,12 @@ After inserting, call FUNC.  If FUNC is nil, instead call
   (buffer-substring-no-properties
    (eshell-beginning-of-output) (eshell-end-of-output)))
 
+(defun eshell-test-file-string (file)
+  "Return the contents of FILE as a string."
+  (with-temp-buffer
+    (insert-file-contents file)
+    (buffer-string)))
+
 (defun eshell-match-output (regexp)
   "Test whether the output of the last command matches REGEXP."
   (string-match-p regexp (eshell-last-output)))
diff --git a/test/lisp/eshell/eshell-tests.el b/test/lisp/eshell/eshell-tests.el
index f16c28cd1ae..c84af62fdbd 100644
--- a/test/lisp/eshell/eshell-tests.el
+++ b/test/lisp/eshell/eshell-tests.el
@@ -138,6 +138,12 @@ This test uses a pipeline for the command."
         (forward-line)
         (should (looking-at "bye\n"))))))
 
+(ert-deftest eshell-test/eshell-command/output-file ()
+  "Test that `eshell-command' can write to a file."
+  (ert-with-temp-file temp-file :text "initial"
+    (eshell-command "echo more" temp-file)
+    (should (equal (eshell-test-file-string temp-file) "moreinitial"))))
+
 (ert-deftest eshell-test/command-running-p ()
   "Modeline should show no command running"
   (with-temp-eshell