test(external-open): cover xdg-open, open-this-file-with, find-file-auto

Sibling tests in `test-external-open-lib-*.el` covered the pure helpers (`cj/external-open-command`, `cj/external-open-launcher-p`). This batch covers the user-facing wrappers:

- `cj/xdg-open`: posix path triggers `call-process` with the open program; errors when no file is associated; errors when no command resolves on the host.
- `cj/open-this-file-with`: errors outside a file-visiting buffer; posix path spawns a detached process via `call-process-shell-command` with `nohup ... >/dev/null 2>&1 &`.
- `cj/find-file-auto`: routes a `.mp4` (in `default-open-extensions`) to `cj/xdg-open`, passes `.txt` through to the original `find-file`, and falls through cleanly for a nil filename argument.

Host predicates, call-process, and the underlying `cj/xdg-open` are stubbed throughout.

1 files changed, 120 insertions, 0 deletions

diff --git a/tests/test-external-open-commands.el b/tests/test-external-open-commands.el
new file mode 100644
index 00000000..c0c83a34
--- /dev/null
+++ b/tests/test-external-open-commands.el
@@ -0,0 +1,120 @@
+;;; test-external-open-commands.el --- Tests for external-open commands -*- lexical-binding: t; -*-
+
+;;; Commentary:
+;; Sibling tests in `test-external-open-lib-*.el' cover the pure
+;; `cj/external-open-command' and launcher-p helpers.  This file
+;; covers the user-facing wrappers:
+;;
+;;   cj/xdg-open
+;;   cj/open-this-file-with
+;;   cj/find-file-auto
+;;
+;; Process primitives and host-environment predicates are stubbed.
+
+;;; Code:
+
+(require 'ert)
+(require 'cl-lib)
+
+(add-to-list 'load-path (expand-file-name "modules" user-emacs-directory))
+(require 'external-open)
+
+;;; cj/xdg-open
+
+(ert-deftest test-external-open-xdg-open-runs-call-process-on-posix ()
+  "Normal: a usable command and file yields a `call-process' invocation."
+  (let ((tmp (make-temp-file "test-ext-open-" nil ".tmp"))
+        (call-args nil))
+    (unwind-protect
+        (cl-letf (((symbol-function 'env-windows-p) (lambda () nil))
+                  ((symbol-function 'cj/external-open-command)
+                   (lambda () "/usr/bin/xdg-open"))
+                  ((symbol-function 'call-process)
+                   (lambda (prog _infile _buf _disp &rest args)
+                     (setq call-args (cons prog args))
+                     0)))
+          (cj/xdg-open tmp))
+      (delete-file tmp))
+    (should (equal (car call-args) "/usr/bin/xdg-open"))
+    ;; The file's basename lands somewhere in the args.
+    (let ((basename (file-name-nondirectory tmp)))
+      (should (cl-find-if (lambda (a)
+                            (and (stringp a) (string-match-p basename a)))
+                          call-args)))))
+
+(ert-deftest test-external-open-xdg-open-errors-when-no-file ()
+  "Error: a buffer with no associated file signals user-error."
+  (with-temp-buffer
+    (cl-letf (((symbol-function 'cj/file-from-context) (lambda (_) nil)))
+      (should-error (cj/xdg-open) :type 'user-error))))
+
+(ert-deftest test-external-open-xdg-open-errors-when-no-command ()
+  "Error: an unsupported host environment signals user-error."
+  (let ((tmp (make-temp-file "test-ext-open-no-cmd-" nil ".tmp")))
+    (unwind-protect
+        (cl-letf (((symbol-function 'cj/external-open-command) (lambda () nil)))
+          (should-error (cj/xdg-open tmp) :type 'user-error))
+      (delete-file tmp))))
+
+;;; cj/open-this-file-with
+
+(ert-deftest test-external-open-open-this-file-with-errors-no-file ()
+  "Error: outside a file-visiting buffer signals user-error."
+  (with-temp-buffer
+    (should-error (cj/open-this-file-with "vlc") :type 'user-error)))
+
+(ert-deftest test-external-open-open-this-file-with-spawns-detached-process ()
+  "Normal: posix path invokes `call-process-shell-command' with nohup + bg."
+  (let ((cmd nil))
+    (with-temp-buffer
+      (setq buffer-file-name "/tmp/foo.mp4")
+      (cl-letf (((symbol-function 'env-windows-p) (lambda () nil))
+                ((symbol-function 'call-process-shell-command)
+                 (lambda (c _infile _buf &rest _)
+                   (setq cmd c))))
+        (cj/open-this-file-with "vlc"))
+      (setq buffer-file-name nil))
+    (should (string-match-p "^nohup vlc " cmd))
+    (should (string-match-p "&$" cmd))
+    (should (string-match-p ">/dev/null" cmd))))
+
+;;; cj/find-file-auto
+
+(ert-deftest test-external-open-find-file-auto-routes-media-externally ()
+  "Normal: a `.mp4' filename (in `default-open-extensions') triggers
+`cj/xdg-open' instead of the original `find-file'."
+  (let ((opened nil)
+        (orig-called nil))
+    (cl-letf (((symbol-function 'cj/xdg-open)
+               (lambda (file) (setq opened file)))
+              ;; orig-fun replacement -- shouldn't run for a routed extension.
+              ((symbol-function 'cj/find-file-auto--orig-stub)
+               (lambda (&rest _) (setq orig-called t))))
+      (cj/find-file-auto #'cj/find-file-auto--orig-stub "/tmp/video.mp4"))
+    (should (equal opened "/tmp/video.mp4"))
+    (should-not orig-called)))
+
+(ert-deftest test-external-open-find-file-auto-passes-through-text-files ()
+  "Boundary: a `.txt' filename falls through to the original `find-file'."
+  (let ((opened nil)
+        (orig-args nil))
+    (cl-letf (((symbol-function 'cj/xdg-open)
+               (lambda (file) (setq opened file)))
+              ((symbol-function 'cj/find-file-auto--orig-stub)
+               (lambda (&rest args) (setq orig-args args))))
+      (cj/find-file-auto #'cj/find-file-auto--orig-stub "/tmp/notes.txt"))
+    (should-not opened)
+    (should (equal (car orig-args) "/tmp/notes.txt"))))
+
+(ert-deftest test-external-open-find-file-auto-non-string-passes-through ()
+  "Boundary: a nil filename falls through (the routing only matches strings)."
+  (let ((orig-called nil))
+    (cl-letf (((symbol-function 'cj/xdg-open)
+               (lambda (_) (error "should not be called")))
+              ((symbol-function 'cj/find-file-auto--orig-stub)
+               (lambda (&rest _) (setq orig-called t))))
+      (cj/find-file-auto #'cj/find-file-auto--orig-stub nil))
+    (should orig-called)))
+
+(provide 'test-external-open-commands)
+;;; test-external-open-commands.el ends here