Provide ERT explainer for 'eshell-match-command-output'

This was formerly named 'eshell-command-result-p', but "result" isn't
quite the right terminology, since this function specifically tested
the output of a command, not its Lisp result (as
'eshell-command-result' would return).

* test/lisp/eshell/eshell-tests-helpers.el (eshell-insert-command):
Provide a more-complete docstring.
(eshell-match-result): Rename to...
(eshell-match-output): ... this.
(eshell-match-output--explainer): New function.
(eshell-command-result-p): Rename to...
(eshell-match-command-output): ... this.

* test/lisp/eshell/em-alias-tests.el
* test/lisp/eshell/em-dirs-tests.el
* test/lisp/eshell/em-extpipe-tests.el
* test/lisp/eshell/em-script-tests.el
* test/lisp/eshell/esh-cmd-tests.el
* test/lisp/eshell/esh-proc-tests.el
* test/lisp/eshell/esh-var-tests.el
* test/lisp/eshell/eshell-tests-helpers.el
* test/lisp/eshell/eshell-tests.el: Use 'eshell-match-command-output'.

1 files changed, 25 insertions, 13 deletions

diff --git a/test/lisp/eshell/eshell-tests-helpers.el b/test/lisp/eshell/eshell-tests-helpers.el
index 4ad76ca6978..778087bd755 100644
--- a/test/lisp/eshell/eshell-tests-helpers.el
+++ b/test/lisp/eshell/eshell-tests-helpers.el
@@ -65,24 +65,36 @@ raise an error."
         (error "timed out waiting for subprocess(es)"))
       (sit-for 0.1))))
 
-(defun eshell-insert-command (text &optional func)
-  "Insert a command at the end of the buffer."
+(defun eshell-insert-command (command &optional func)
+  "Insert a COMMAND at the end of the buffer.
+After inserting, call FUNC.  If FUNC is nil, instead call
+`eshell-send-input'."
   (goto-char eshell-last-output-end)
-  (insert-and-inherit text)
+  (insert-and-inherit command)
   (funcall (or func 'eshell-send-input)))
 
-(defun eshell-match-result (regexp)
-  "Check that output of last command matches REGEXP."
-  (should
-   (string-match-p
+(defun eshell-match-output (regexp)
+  "Test whether the output of the last command matches REGEXP."
+  (string-match-p
     regexp (buffer-substring-no-properties
-            (eshell-beginning-of-output) (eshell-end-of-output)))))
-
-(defun eshell-command-result-p (text regexp &optional func)
-  "Insert a command at the end of the buffer."
-  (eshell-insert-command text func)
+            (eshell-beginning-of-output) (eshell-end-of-output))))
+
+(defun eshell-match-output--explainer (regexp)
+  "Explain the result of `eshell-match-output'."
+  `(mismatched-output
+    (command ,(buffer-substring-no-properties
+               eshell-last-input-start eshell-last-input-end))
+    (output ,(buffer-substring-no-properties
+              (eshell-beginning-of-output) (eshell-end-of-output)))
+    (regexp ,regexp)))
+
+(put 'eshell-match-output 'ert-explainer #'eshell-match-output--explainer)
+
+(defun eshell-match-command-output (command regexp &optional func)
+  "Insert a COMMAND at the end of the buffer and match the output with REGEXP."
+  (eshell-insert-command command func)
   (eshell-wait-for-subprocess)
-  (eshell-match-result regexp))
+  (should (eshell-match-output regexp)))
 
 (defvar eshell-history-file-name)