Simplify Eshell handle functions and add tests/documentation

* lisp/eshell/esh-arg.el (eshell-parse-argument-hook): Explain how to
use 'eshell-finish-arg'.

* lisp/eshell/esh-io.el (eshell-create-handles): Only call
'eshell-get-target' for stderr if necessary.
(eshell-protect-handles): Use 'dotimes'.
(eshell-set-output-handle): Pass HANDLES and fix an edge case with
setting a duplicate TARGET.

* test/lisp/eshell/eshell-tests-helpers.el (eshell-with-temp-buffer):
New macro.

* test/lisp/eshell/esh-cmd-tests.el (esh-cmd-test/quoted-lisp-form)
(esh-cmd-test/backquoted-lisp-form)
(esh-cmd-test/backquoted-lisp-form/splice): New tests.

* test/lisp/eshell/eshell-tests.el (eshell-test/redirect-buffer)
(eshell-test/redirect-buffer-escaped): Move to...
* test/lisp/eshell/esh-io-tests.el: ... here, and add other I/O tests.

* doc/misc/eshell.texi (Arguments): Add documentation for special
argument types.
(Input/Output): Expand documentation for redirection and pipelines.

1 files changed, 10 insertions, 0 deletions

diff --git a/test/lisp/eshell/eshell-tests-helpers.el b/test/lisp/eshell/eshell-tests-helpers.el
index 8f0f993447f..73abfcbb557 100644
--- a/test/lisp/eshell/eshell-tests-helpers.el
+++ b/test/lisp/eshell/eshell-tests-helpers.el
@@ -51,6 +51,16 @@ See `eshell-wait-for-subprocess'.")
            (let (kill-buffer-query-functions)
              (kill-buffer eshell-buffer)))))))
 
+(defmacro eshell-with-temp-buffer (bufname text &rest body)
+  "Create a temporary buffer containing TEXT and evaluate BODY there.
+BUFNAME will be set to the name of the temporary buffer."
+  (declare (indent 2))
+  `(with-temp-buffer
+     (insert ,text)
+     (rename-buffer "eshell-temp-buffer" t)
+     (let ((,bufname (buffer-name)))
+       ,@body)))
+
 (defun eshell-wait-for-subprocess (&optional all)
   "Wait until there is no interactive subprocess running in Eshell.
 If ALL is non-nil, wait until there are no Eshell subprocesses at