Add regression tests for Eshell completions

* lisp/eshell/esh-cmd.el (eshell-complete-lisp-symbols): Fix
docstring.

* test/lisp/eshell/em-cmpl-tests.el: New file.

2 files changed, 171 insertions, 1 deletions

diff --git a/lisp/eshell/esh-cmd.el b/lisp/eshell/esh-cmd.el
index 99c3d7f627d..b5f1d60ff18 100644
--- a/lisp/eshell/esh-cmd.el
+++ b/lisp/eshell/esh-cmd.el
@@ -343,7 +343,7 @@ This only returns external (non-Lisp) processes."
 	      #'eshell-complete-lisp-symbols nil t)))
 
 (defun eshell-complete-lisp-symbols ()
-  "If there is a user reference, complete it."
+  "If there is a Lisp symbol, complete it."
   (let ((arg (pcomplete-actual-arg)))
     (when (string-match (concat "\\`" eshell-lisp-regexp) arg)
       (setq pcomplete-stub (substring arg (match-end 0))
diff --git a/test/lisp/eshell/em-cmpl-tests.el b/test/lisp/eshell/em-cmpl-tests.el
new file mode 100644
index 00000000000..32b0781dd75
--- /dev/null
+++ b/test/lisp/eshell/em-cmpl-tests.el
@@ -0,0 +1,170 @@
+;;; em-cmpl-tests.el --- em-cmpl test suite  -*- lexical-binding:t -*-
+
+;; Copyright (C) 2023 Free Software Foundation, Inc.
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs is free software: you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; GNU Emacs is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;; Tests for Eshell's interactive completion.
+
+;;; Code:
+
+(require 'ert)
+(require 'eshell)
+(require 'em-cmpl)
+(require 'em-dirs)
+(require 'em-hist)
+(require 'em-tramp)
+(require 'em-unix)
+
+(require 'eshell-tests-helpers
+         (expand-file-name "eshell-tests-helpers"
+                           (file-name-directory (or load-file-name
+                                                    default-directory))))
+
+(defvar eshell-test-value nil)
+
+(defun eshell-insert-and-complete (input)
+  "Insert INPUT and invoke completion, returning the result."
+  (insert input)
+  (completion-at-point)
+  (eshell-get-old-input))
+
+;;; Tests:
+
+(ert-deftest em-cmpl-test/parse-arguments/pipeline ()
+  "Test that parsing arguments for completion discards earlier commands."
+  (with-temp-eshell
+   (let ((eshell-test-value '("foo" "bar")))
+     (insert "echo hi | cat")
+     (should (equal (car (eshell-complete-parse-arguments))
+                    '("cat"))))))
+
+(ert-deftest em-cmpl-test/parse-arguments/multiple-dots ()
+  "Test parsing arguments with multiple dots like \".../\"."
+  (with-temp-eshell
+   (insert "echo .../file.txt")
+   (should (equal (car (eshell-complete-parse-arguments))
+                  '("echo" "../../file.txt")))))
+
+(ert-deftest em-cmpl-test/parse-arguments/variable/numeric ()
+  "Test parsing arguments with a numeric variable interpolation."
+  (with-temp-eshell
+   (let ((eshell-test-value 42))
+     (insert "echo $eshell-test-value")
+     (should (equal (car (eshell-complete-parse-arguments))
+                    '("echo" "42"))))))
+
+(ert-deftest em-cmpl-test/parse-arguments/variable/nil ()
+  "Test parsing arguments with a nil variable interpolation."
+  (with-temp-eshell
+   (let ((eshell-test-value nil))
+     (insert "echo $eshell-test-value")
+     (should (equal (car (eshell-complete-parse-arguments))
+                    '("echo" ""))))))
+
+(ert-deftest em-cmpl-test/parse-arguments/variable/list ()
+  "Test parsing arguments with a list variable interpolation."
+  (with-temp-eshell
+   (let ((eshell-test-value '("foo" "bar")))
+     (insert "echo $eshell-test-value")
+     (should (equal (car (eshell-complete-parse-arguments))
+                    '("echo" ("foo" "bar")))))))
+
+(ert-deftest em-cmpl-test/file-completion/unique ()
+  "Test completion of file names when there's a unique result."
+  (with-temp-eshell
+   (ert-with-temp-directory default-directory
+     (write-region nil nil (expand-file-name "file.txt"))
+     (should (equal (eshell-insert-and-complete "echo fi")
+                    "echo file.txt ")))))
+
+(ert-deftest em-cmpl-test/file-completion/non-unique ()
+  "Test completion of file names when there are multiple results."
+  (with-temp-eshell
+   (ert-with-temp-directory default-directory
+     (write-region nil nil (expand-file-name "file.txt"))
+     (write-region nil nil (expand-file-name "file.el"))
+     (should (equal (eshell-insert-and-complete "echo fi")
+                    "echo file."))
+     ;; Now try completing again.
+     (let ((minibuffer-message-timeout 0)
+           (inhibit-message t))
+       (completion-at-point))
+     ;; FIXME: We can't use `current-message' here.
+     (with-current-buffer (messages-buffer)
+       (save-excursion
+         (goto-char (point-max))
+         (forward-line -1)
+         (should (looking-at "Complete, but not unique")))))))
+
+(ert-deftest em-cmpl-test/file-completion/after-list ()
+  "Test completion of file names after previous list arguments.
+See bug#59956."
+  (with-temp-eshell
+   (ert-with-temp-directory default-directory
+     (write-region nil nil (expand-file-name "file.txt"))
+     (should (equal (eshell-insert-and-complete "echo (list 1 2) fi")
+                    "echo (list 1 2) file.txt ")))))
+
+(ert-deftest em-cmpl-test/lisp-symbol-completion ()
+  "Test completion of Lisp forms like \"#'symbol\" and \"`symbol\".
+See <lisp/eshell/esh-cmd.el>."
+  (with-temp-eshell
+   (should (equal (eshell-insert-and-complete "echo #'system-nam")
+                  "echo #'system-name ")))
+  (with-temp-eshell
+   (should (equal (eshell-insert-and-complete "echo `system-nam")
+                  "echo `system-name "))))
+
+(ert-deftest em-cmpl-test/lisp-function-completion ()
+  "Test completion of Lisp forms like \"(func)\".
+See <lisp/eshell/esh-cmd.el>."
+  (with-temp-eshell
+   (should (equal (eshell-insert-and-complete "echo (eshell/ech")
+                  "echo (eshell/echo"))))
+
+(ert-deftest em-cmpl-test/variable-ref-completion ()
+  "Test completion of variable references like \"$var\".
+See <lisp/eshell/esh-var.el>."
+  (with-temp-eshell
+   (should (equal (eshell-insert-and-complete "echo $system-nam")
+                  "echo $system-name "))))
+
+(ert-deftest em-cmpl-test/variable-assign-completion ()
+  "Test completion of variable assignments like \"var=value\".
+See <lisp/eshell/esh-var.el>."
+  (with-temp-eshell
+   (ert-with-temp-directory default-directory
+     (write-region nil nil (expand-file-name "file.txt"))
+     (should (equal (eshell-insert-and-complete "VAR=f")
+                    "VAR=file.txt ")))))
+
+(ert-deftest em-cmpl-test/user-ref-completion ()
+  "Test completeion of user references like \"~user\".
+See <lisp/eshell/em-dirs.el>."
+  (unwind-protect
+      (with-temp-eshell
+       (cl-letf (((symbol-function 'eshell-read-user-names)
+                  (lambda () (setq eshell-user-names '((1234 . "user"))))))
+         ;; FIXME: Should this really add a space at the end?
+         (should (equal (eshell-insert-and-complete "echo ~us")
+                        "echo ~user/ "))))
+    ;; Clear the cached user names we set above.
+    (setq eshell-user-names nil)))
+
+;;; em-cmpl-tests.el ends here