Fix Tramp test environment on hydra.nixos.org

* lisp/emacs-lisp/ert-x.el (tramp-remote-path): Declare.  Adapt
`tramp-remote-path' on hydra.  (Bug#56424)

* test/lisp/dnd-tests.el (dnd-tests-begin-drag-files): Remove instrumentation.

* test/lisp/filenotify-tests.el:
* test/lisp/shadowfile-tests.el:
* test/lisp/net/tramp-tests.el: Do not adapt `tramp-remote-path'.

lisp/emacs-lisp/ert-x.el

@@ -488,9 +488,13 @@ The same keyword arguments are supported as in
   (string-match "Apple \\(LLVM\\|[Cc]lang\\)\\|Xcode\\.app"
                 (shell-command-to-string "gcc --version")))
 
-
-(defvar tramp-methods)
 (defvar tramp-default-host-alist)
+(defvar tramp-methods)
+(defvar tramp-remote-path)
+
+;; This should happen on hydra only.
+(when (getenv "EMACS_HYDRA_CI")
+  (add-to-list 'tramp-remote-path 'tramp-own-remote-path))
 
 ;; If this defconst is used in a test file, `tramp' shall be loaded
 ;; prior `ert-x'.  There is no default value on w32 systems, which

test/lisp/dnd-tests.el

@@ -274,7 +274,6 @@ This function only tries to handle strings."
   (skip-unless (and (dnd-tests-remote-accessible-p)
                     ;; TODO: make these tests work under X.
                     (not (eq window-system 'x))))
-  (let ((tramp-verbose (if (getenv "EMACS_HYDRA_CI") 10 3)))
   (let ((normal-temp-file (expand-file-name (make-temp-name "dnd-test")
                                             temporary-file-directory))
         (normal-temp-file-1 (expand-file-name (make-temp-name "dnd-test")
@@ -384,14 +383,9 @@ This function only tries to handle strings."
           ;; And when all remote files are inaccessible.
           (should-error (dnd-begin-drag-files (list nonexistent-remote-file
                                                     nonexistent-remote-file-1))))
-      (when (getenv "EMACS_HYDRA_CI")
-        (dolist (buf (tramp-list-tramp-buffers))
-	  (message ";; %s\n%s" buf (tramp-get-buffer-string buf))
-	  (kill-buffer buf)))
       (delete-file normal-temp-file)
       (delete-file normal-temp-file-1)
       (delete-file remote-temp-file))))
-  )
 
 (ert-deftest dnd-tests-get-local-file-uri ()
   (should (equal (dnd-get-local-file-uri "file://localhost/path/to/foo")

test/lisp/filenotify-tests.el

@@ -178,10 +178,6 @@ Return nil when any other file notification watch is still active."
       tramp-allow-unsafe-temporary-files
       (or tramp-allow-unsafe-temporary-files noninteractive))
 
-;; This should happen on hydra only.
-(when (getenv "EMACS_HYDRA_CI")
-  (add-to-list 'tramp-remote-path 'tramp-own-remote-path))
-
 (defun file-notify--test-add-watch (file flags callback)
   "Like `file-notify-add-watch', but also passing FILE to CALLBACK."
   (file-notify-add-watch file flags

test/lisp/net/tramp-tests.el

@@ -128,6 +128,7 @@ A resource file is in the resource directory as per
       `(expand-file-name ,file (ert-resource-directory)))))
 
 ;; `ert-remote-temporary-file-directory' was introduced in Emacs 29.1.
+;; Adapting `tramp-remote-path' happens also there.
 (unless (boundp 'ert-remote-temporary-file-directory)
   (eval-and-compile
     ;; There is no default value on w32 systems, which could work out
@@ -152,7 +153,11 @@ A resource file is in the resource directory as per
           (unless (and (null noninteractive) (file-directory-p "~/"))
             (setenv "HOME" temporary-file-directory))
           (format "/mock::%s" temporary-file-directory)))
-      "Temporary directory for remote file tests.")))
+      "Temporary directory for remote file tests.")
+
+    ;; This should happen on hydra only.
+    (when (getenv "EMACS_HYDRA_CI")
+      (add-to-list 'tramp-remote-path 'tramp-own-remote-path))))
 
 ;; Beautify batch mode.
 (when noninteractive
@@ -178,10 +183,6 @@ A resource file is in the resource directory as per
       tramp-persistency-file-name nil
       tramp-verbose 0)
 
-;; This should happen on hydra only.
-(when (getenv "EMACS_HYDRA_CI")
-  (add-to-list 'tramp-remote-path 'tramp-own-remote-path))
-
 (defvar tramp--test-enabled-checked nil
   "Cached result of `tramp--test-enabled'.
 If the function did run, the value is a cons cell, the `cdr'

test/lisp/shadowfile-tests.el

@@ -55,10 +55,6 @@
       ert-remote-temporary-file-directory
       (ignore-errors (file-truename ert-remote-temporary-file-directory)))
 
-;; This should happen on hydra only.
-(when (getenv "EMACS_HYDRA_CI")
-  (add-to-list 'tramp-remote-path 'tramp-own-remote-path))
-
 (defconst shadow-test-info-file
   (expand-file-name "shadows_test" temporary-file-directory)
   "File to keep shadow information in during tests.")