refactor(dirvish): extract cj/--dired-resolve-display-path helper

`cj/dired-copy-path-as-kill' was a 57-line procedural body with the path-resolution branching mixed into the kill-ring write and the user-visible message. Lift the four-way decision (force-absolute / project-relative / home-relative / bare absolute) into `cj/--dired-resolve-display-path', a pure function from (FILE PROJECT-ROOT HOME-DIR FORCE-ABSOLUTE) to (PATH . PATH-TYPE). The wrapper now reads as: get the dired file, ask the helper how to display it, format-or-pass-through, kill-new, message.

Seven Normal/Boundary tests cover each branch: project-relative, home-relative, the home-itself "~" glyph, absolute fallback, force-absolute beating both project and home, and project taking precedence over home when both apply.

1 files changed, 86 insertions, 0 deletions

diff --git a/tests/test-dirvish-config-resolve-display-path.el b/tests/test-dirvish-config-resolve-display-path.el
new file mode 100644
index 00000000..dbd36a81
--- /dev/null
+++ b/tests/test-dirvish-config-resolve-display-path.el
@@ -0,0 +1,86 @@
+;;; test-dirvish-config-resolve-display-path.el --- Tests for the path-resolution helper -*- lexical-binding: t; -*-
+
+;;; Commentary:
+;; `cj/--dired-resolve-display-path' is the pure logic underneath
+;; `cj/dired-copy-path-as-kill'.  Given the absolute FILE, the active
+;; PROJECT-ROOT (or nil), the user's HOME-DIR, and a FORCE-ABSOLUTE
+;; flag, the helper returns a (PATH . PATH-TYPE) cons describing what
+;; to copy and how to label it.  The interactive wrapper does the
+;; clipboard write and the user-visible message.
+
+;;; Code:
+
+(require 'ert)
+(require 'package)
+
+(setq package-user-dir (expand-file-name "elpa" user-emacs-directory))
+(package-initialize)
+(add-to-list 'load-path (expand-file-name "modules" user-emacs-directory))
+(add-to-list 'load-path (expand-file-name "elpa/dirvish-2.3.0/extensions"
+                                          user-emacs-directory))
+(require 'user-constants)
+(require 'keybindings)
+(require 'dirvish-config)
+
+(ert-deftest test-cj--dired-resolve-display-path-project-relative ()
+  "Normal: file inside a project returns a project-relative path."
+  (should (equal (cj/--dired-resolve-display-path
+                  "/home/me/code/proj/src/main.el"
+                  "/home/me/code/proj/"
+                  "/home/me")
+                 (cons "src/main.el" "project-relative"))))
+
+(ert-deftest test-cj--dired-resolve-display-path-home-relative ()
+  "Normal: file under home but not in any project returns a ~/-prefixed path."
+  (should (equal (cj/--dired-resolve-display-path
+                  "/home/me/notes/today.org"
+                  nil
+                  "/home/me")
+                 (cons "~/notes/today.org" "home-relative"))))
+
+(ert-deftest test-cj--dired-resolve-display-path-home-itself ()
+  "Boundary: file IS the home dir -> path is the bare ~ glyph."
+  (should (equal (cj/--dired-resolve-display-path
+                  "/home/me"
+                  nil
+                  "/home/me")
+                 (cons "~" "home-relative"))))
+
+(ert-deftest test-cj--dired-resolve-display-path-absolute-fallback ()
+  "Boundary: file outside home and no project -> absolute path."
+  (should (equal (cj/--dired-resolve-display-path
+                  "/etc/hosts"
+                  nil
+                  "/home/me")
+                 (cons "/etc/hosts" "absolute"))))
+
+(ert-deftest test-cj--dired-resolve-display-path-force-absolute-overrides-project ()
+  "Normal: FORCE-ABSOLUTE wins over an active project root."
+  (should (equal (cj/--dired-resolve-display-path
+                  "/home/me/code/proj/src/main.el"
+                  "/home/me/code/proj/"
+                  "/home/me"
+                  t)
+                 (cons "/home/me/code/proj/src/main.el" "absolute"))))
+
+(ert-deftest test-cj--dired-resolve-display-path-force-absolute-overrides-home ()
+  "Normal: FORCE-ABSOLUTE wins over a home-prefix match."
+  (should (equal (cj/--dired-resolve-display-path
+                  "/home/me/notes/today.org"
+                  nil
+                  "/home/me"
+                  t)
+                 (cons "/home/me/notes/today.org" "absolute"))))
+
+(ert-deftest test-cj--dired-resolve-display-path-project-precedes-home ()
+  "Normal: when a file is BOTH inside a project and under home, the project
+view wins.  This matches the original code -- projects are usually under
+home and the project-relative form reads more usefully."
+  (should (equal (cj/--dired-resolve-display-path
+                  "/home/me/code/proj/src/main.el"
+                  "/home/me/code/proj/"
+                  "/home/me")
+                 (cons "src/main.el" "project-relative"))))
+
+(provide 'test-dirvish-config-resolve-display-path)
+;;; test-dirvish-config-resolve-display-path.el ends here