Move Eshell variable interpolation tests to their own file

* test/lisp/eshell/eshell-tests.el (eshell-test/interp-cmd)
(eshell-test/interp-lisp, eshell-test/interp-temp-cmd)
(eshell-test/interp-concat, eshell-test/interp-concat-lisp)
(eshell-test/interp-concat2, eshell-test/interp-concat-lisp2)
(eshell-test/interp-cmd-external)
(eshell-test/interp-cmd-external-concat, eshell-test/window-height)
(eshell-test/window-width, eshell-test/last-result-var)
(eshell-test/last-result-var2, eshell-test/last-arg-var):
Move from here...

* test/lisp/eshell/esh-var-test.el (esh-var-test/interp-lisp)
(esh-var-test/interp-cmd, esh-var-test/interp-cmd-external)
(esh-var-test/interp-temp-cmd, esh-var-test/interp-concat-lisp)
(esh-var-test/interp-concat-lisp2, esh-var-test/interp-concat-cmd)
(esh-var-test/interp-concat-cmd2)
(esh-var-test/interp-concat-cmd-external, esh-var-test/window-height)
(esh-var-test/window-width, esh-var-test/last-result-var)
(esh-var-test/last-result-var2, esh-var-test/last-arg-var):
... to here.

2 files changed, 111 insertions, 68 deletions

diff --git a/test/lisp/eshell/esh-var-tests.el b/test/lisp/eshell/esh-var-tests.el
new file mode 100644
index 00000000000..8d803e5ca49
--- /dev/null
+++ b/test/lisp/eshell/esh-var-tests.el
@@ -0,0 +1,111 @@
+;;; esh-var-tests.el --- esh-var test suite  -*- lexical-binding:t -*-
+
+;; Copyright (C) 2022 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 variable handling.
+
+;;; Code:
+
+(require 'ert)
+(require 'esh-mode)
+(require 'eshell)
+
+(require 'eshell-tests-helpers
+         (expand-file-name "eshell-tests-helpers"
+                           (file-name-directory (or load-file-name
+                                                    default-directory))))
+
+;;; Tests:
+
+
+;; Variable interpolation
+
+(ert-deftest esh-var-test/interp-lisp ()
+  "Interpolate Lisp form evaluation"
+  (should (equal (eshell-test-command-result "+ $(+ 1 2) 3") 6)))
+
+(ert-deftest esh-var-test/interp-cmd ()
+  "Interpolate command result"
+  (should (equal (eshell-test-command-result "+ ${+ 1 2} 3") 6)))
+
+(ert-deftest esh-var-test/interp-cmd-external ()
+  "Interpolate command result from external command"
+  (skip-unless (executable-find "echo"))
+  (with-temp-eshell
+   (eshell-command-result-p "echo ${*echo hi}"
+                            "hi\n")))
+
+(ert-deftest esh-var-test/interp-temp-cmd ()
+  "Interpolate command result redirected to temp file"
+  (should (equal (eshell-test-command-result "cat $<echo hi>") "hi")))
+
+(ert-deftest esh-var-test/interp-concat-lisp ()
+  "Interpolate and concat Lisp form"
+  (should (equal (eshell-test-command-result "+ $(+ 1 2)3 3") 36)))
+
+(ert-deftest esh-var-test/interp-concat-lisp2 ()
+  "Interpolate and concat two Lisp forms"
+  (should (equal (eshell-test-command-result "+ $(+ 1 2)$(+ 1 2) 3") 36)))
+
+(ert-deftest esh-var-test/interp-concat-cmd ()
+  "Interpolate and concat command"
+  (should (equal (eshell-test-command-result "+ ${+ 1 2}3 3") 36)))
+
+(ert-deftest esh-var-test/interp-concat-cmd2 ()
+  "Interpolate and concat two commands"
+  (should (equal (eshell-test-command-result "+ ${+ 1 2}${+ 1 2} 3") 36)))
+
+(ert-deftest esh-var-test/interp-concat-cmd-external ()
+  "Interpolate command result from external command with concatenation"
+  (skip-unless (executable-find "echo"))
+  (with-temp-eshell
+   (eshell-command-result-p "echo ${echo hi}-${*echo there}"
+                            "hi-there\n")))
+
+
+;; Built-in variables
+
+(ert-deftest esh-var-test/window-height ()
+  "$LINES should equal (window-height)"
+  (should (eshell-test-command-result "= $LINES (window-height)")))
+
+(ert-deftest esh-var-test/window-width ()
+  "$COLUMNS should equal (window-width)"
+  (should (eshell-test-command-result "= $COLUMNS (window-width)")))
+
+(ert-deftest esh-var-test/last-result-var ()
+  "Test using the \"last result\" ($$) variable"
+  (with-temp-eshell
+   (eshell-command-result-p "+ 1 2; + $$ 2"
+                            "3\n5\n")))
+
+(ert-deftest esh-var-test/last-result-var2 ()
+  "Test using the \"last result\" ($$) variable twice"
+  (with-temp-eshell
+   (eshell-command-result-p "+ 1 2; + $$ $$"
+                             "3\n6\n")))
+
+(ert-deftest esh-var-test/last-arg-var ()
+  "Test using the \"last arg\" ($_) variable"
+  (with-temp-eshell
+   (eshell-command-result-p "+ 1 2; + $_ 4"
+                             "3\n6\n")))
+
+;; esh-var-tests.el ends here
diff --git a/test/lisp/eshell/eshell-tests.el b/test/lisp/eshell/eshell-tests.el
index eff4edd62c7..e31db07c619 100644
--- a/test/lisp/eshell/eshell-tests.el
+++ b/test/lisp/eshell/eshell-tests.el
@@ -85,48 +85,6 @@ Test that trailing arguments outside the subcommand are ignored.
 e.g. \"{(+ 1 2)} 3\" => 3"
   (should (equal (eshell-test-command-result "{(+ 1 2)} 3") 3)))
 
-(ert-deftest eshell-test/interp-cmd ()
-  "Interpolate command result"
-  (should (equal (eshell-test-command-result "+ ${+ 1 2} 3") 6)))
-
-(ert-deftest eshell-test/interp-lisp ()
-  "Interpolate Lisp form evaluation"
-  (should (equal (eshell-test-command-result "+ $(+ 1 2) 3") 6)))
-
-(ert-deftest eshell-test/interp-temp-cmd ()
-  "Interpolate command result redirected to temp file"
-  (should (equal (eshell-test-command-result "cat $<echo hi>") "hi")))
-
-(ert-deftest eshell-test/interp-concat ()
-  "Interpolate and concat command"
-  (should (equal (eshell-test-command-result "+ ${+ 1 2}3 3") 36)))
-
-(ert-deftest eshell-test/interp-concat-lisp ()
-  "Interpolate and concat Lisp form"
-  (should (equal (eshell-test-command-result "+ $(+ 1 2)3 3") 36)))
-
-(ert-deftest eshell-test/interp-concat2 ()
-  "Interpolate and concat two commands"
-  (should (equal (eshell-test-command-result "+ ${+ 1 2}${+ 1 2} 3") 36)))
-
-(ert-deftest eshell-test/interp-concat-lisp2 ()
-  "Interpolate and concat two Lisp forms"
-  (should (equal (eshell-test-command-result "+ $(+ 1 2)$(+ 1 2) 3") 36)))
-
-(ert-deftest eshell-test/interp-cmd-external ()
-  "Interpolate command result from external command"
-  (skip-unless (executable-find "echo"))
-  (with-temp-eshell
-   (eshell-command-result-p "echo ${*echo hi}"
-                            "hi\n")))
-
-(ert-deftest eshell-test/interp-cmd-external-concat ()
-  "Interpolate command result from external command with concatenation"
-  (skip-unless (executable-find "echo"))
-  (with-temp-eshell
-   (eshell-command-result-p "echo ${echo hi}-${*echo there}"
-                            "hi-there\n")))
-
 (ert-deftest eshell-test/pipe-headproc ()
   "Check that piping a non-process to a process command waits for the process"
   (skip-unless (executable-find "cat"))
@@ -152,32 +110,6 @@ e.g. \"{(+ 1 2)} 3\" => 3"
    (eshell-wait-for-subprocess)
    (eshell-match-result "OLLEH\n")))
 
-(ert-deftest eshell-test/window-height ()
-  "$LINES should equal (window-height)"
-  (should (eshell-test-command-result "= $LINES (window-height)")))
-
-(ert-deftest eshell-test/window-width ()
-  "$COLUMNS should equal (window-width)"
-  (should (eshell-test-command-result "= $COLUMNS (window-width)")))
-
-(ert-deftest eshell-test/last-result-var ()
-  "Test using the \"last result\" ($$) variable"
-  (with-temp-eshell
-   (eshell-command-result-p "+ 1 2; + $$ 2"
-                            "3\n5\n")))
-
-(ert-deftest eshell-test/last-result-var2 ()
-  "Test using the \"last result\" ($$) variable twice"
-  (with-temp-eshell
-   (eshell-command-result-p "+ 1 2; + $$ $$"
-                             "3\n6\n")))
-
-(ert-deftest eshell-test/last-arg-var ()
-  "Test using the \"last arg\" ($_) variable"
-  (with-temp-eshell
-   (eshell-command-result-p "+ 1 2; + $_ 4"
-                             "3\n6\n")))
-
 (ert-deftest eshell-test/inside-emacs-var ()
   "Test presence of \"INSIDE_EMACS\" in subprocesses"
   (with-temp-eshell