* test/lisp/net/tramp-tests.el (tramp--test-check-files): Make it robust.

test/lisp/net/tramp-tests.el

@@ -2169,18 +2169,6 @@ This requires restrictions of file name syntax."
 	   (process-environment process-environment))
       (unwind-protect
 	  (progn
-	    ;; Add environment variables.
-	    (dolist (elt files)
-	      ;; The check command (heredoc file) does not support
-	      ;; environment variables with leading spaces.
-	      (let* ((elt (replace-regexp-in-string "^\\s-+" "" elt))
-		     (envvar (concat "VAR_" (upcase (md5 elt)))))
-		(setenv envvar elt)))
-
-	    ;; We force a reconnect, in order to have a clean environment.
-	    (tramp-cleanup-connection
-	     (tramp-dissect-file-name tramp-test-temporary-file-directory)
-	     'keep-debug 'keep-password)
 	    (make-directory tmp-name1)
 	    (make-directory tmp-name2)
 
@@ -2310,30 +2298,23 @@ This requires restrictions of file name syntax."
 
 	    ;; Check, that environment variables are set correctly.
 	    (when (and tramp--test-expensive-test (tramp--test-sh-p))
-	      (dolist (elt process-environment)
-		(when (string-match "^VAR_" elt)
-		  (let* ((default-directory tramp-test-temporary-file-directory)
-			 (shell-file-name "/bin/sh")
-			 (heredoc (md5 (current-time-string)))
-			 (envvar (car (split-string elt "=" t)))
-			 (file1 (tramp-compat-file-name-unquote
-				 (expand-file-name "bar" tmp-name1))))
-		    ;; Cleanup.
-		    (ignore-errors (delete-file file1))
-		    ;; Save the variable in a file.  The echo command
-		    ;; does not work properly, it suppresses leading/
-		    ;; trailing spaces as well as tabs.
-		    (shell-command-to-string
-		     (format
-		      "cat <<%s >%s\n$%s\n%s"
-		      heredoc (file-remote-p file1 'localname) envvar heredoc))
-		    (with-temp-buffer
-		      (insert-file-contents file1)
-		      (should
-		       (string-equal
-			(buffer-string) (concat (getenv envvar) "\n"))))
-		    (delete-file file1)
-		    (should-not (file-exists-p file1)))))))
+	      (dolist (elt files)
+		(let ((envvar (concat "VAR_" (upcase (md5 elt))))
+		      (default-directory tramp-test-temporary-file-directory)
+		      (process-environment process-environment))
+		  (setenv envvar elt)
+		  ;; The value of PS1 could confuse Tramp's detection
+		  ;; of process output.  So we unset it temporarily.
+		  (setenv "PS1")
+		  (with-temp-buffer
+		    (should (zerop (process-file "env" nil t nil)))
+		    (goto-char (point-min))
+		    (should
+		     (re-search-forward
+		      (format
+		       "^%s=%s$"
+		       (regexp-quote envvar)
+		       (regexp-quote (getenv envvar))))))))))
 
 	;; Cleanup.
 	(ignore-errors (delete-directory tmp-name1 'recursive))