test(ui-theme): cover switch-themes, save-to-file, get-active-name

1 files changed, 110 insertions, 0 deletions

diff --git a/tests/test-ui-theme-commands.el b/tests/test-ui-theme-commands.el
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+++ b/tests/test-ui-theme-commands.el
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+;;; test-ui-theme-commands.el --- Tests for ui-theme command wrappers -*- lexical-binding: t; -*-
+
+;;; Commentary:
+;; Sibling `test-ui-theme-persistence.el' covers the read/write/load
+;; pipeline.  This file covers the four remaining helpers:
+;;
+;;   cj/switch-themes
+;;   cj/save-theme-to-file
+;;   cj/get-active-theme-name
+;;   cj/load-fallback-theme
+
+;;; Code:
+
+(require 'ert)
+(require 'cl-lib)
+
+(add-to-list 'load-path (expand-file-name "modules" user-emacs-directory))
+(require 'ui-theme)
+
+;; Top-level defvars so let-bindings reach the dynamic var under
+;; lexical scope.
+(defvar custom-enabled-themes nil)
+
+;;; cj/get-active-theme-name
+
+(ert-deftest test-ui-theme-get-active-name-returns-first-enabled ()
+  "Normal: with an enabled theme, the name of the first one is returned."
+  (let ((custom-enabled-themes '(modus-vivendi tango)))
+    (should (equal "modus-vivendi" (cj/get-active-theme-name)))))
+
+(ert-deftest test-ui-theme-get-active-name-falls-back-when-none ()
+  "Boundary: with no enabled themes, fallback-theme-name is returned."
+  (let ((custom-enabled-themes nil)
+        (fallback-theme-name "modus-vivendi"))
+    (should (equal "modus-vivendi" (cj/get-active-theme-name)))))
+
+;;; cj/save-theme-to-file
+
+(ert-deftest test-ui-theme-save-writes-active-name-to-file ()
+  "Normal: save-to-file writes the active theme name into theme-file."
+  (let ((file (make-temp-file "ui-theme-save-"))
+        (custom-enabled-themes '(tango-dark)))
+    (unwind-protect
+        (let ((theme-file file))
+          (cl-letf (((symbol-function 'message) #'ignore))
+            (cj/save-theme-to-file))
+          (should (equal "tango-dark" (cj/theme-read-file-contents file))))
+      (delete-file file))))
+
+(ert-deftest test-ui-theme-save-reports-when-unwriteable ()
+  "Error: when write fails, save-to-file reports via `message' and
+does not raise."
+  (let ((custom-enabled-themes '(tango-dark))
+        (messaged nil))
+    (cl-letf (((symbol-function 'cj/theme-write-file-contents)
+               (lambda (&rest _) nil))
+              ((symbol-function 'message)
+               (lambda (fmt &rest args)
+                 (setq messaged (apply #'format fmt args)))))
+      (cj/save-theme-to-file))
+    (should (string-match-p "Cannot save theme" messaged))))
+
+;;; cj/load-fallback-theme
+
+(ert-deftest test-ui-theme-load-fallback-disables-then-loads ()
+  "Normal: load-fallback-theme disables all then loads the fallback."
+  (let ((fallback-theme-name "modus-vivendi")
+        (custom-enabled-themes '(old-one old-two))
+        disabled loaded)
+    (cl-letf (((symbol-function 'disable-theme)
+               (lambda (theme) (push theme disabled)))
+              ((symbol-function 'load-theme)
+               (lambda (theme &optional _no-confirm _no-enable)
+                 (push theme loaded)))
+              ((symbol-function 'message) #'ignore))
+      (cj/load-fallback-theme "boom"))
+    (should (equal (sort (copy-sequence disabled) #'string<) '(old-one old-two)))
+    (should (equal loaded '(modus-vivendi)))))
+
+;;; cj/switch-themes
+
+(ert-deftest test-ui-theme-switch-disables-loads-then-saves ()
+  "Normal: switch-themes routes through completing-read, disables enabled
+themes, loads the chosen one, and saves the name to disk."
+  (let ((file (make-temp-file "ui-theme-switch-"))
+        (custom-enabled-themes '(currently-on))
+        disabled loaded)
+    (unwind-protect
+        (let ((theme-file file))
+          (cl-letf (((symbol-function 'completing-read)
+                     (lambda (&rest _) "modus-vivendi"))
+                    ((symbol-function 'custom-available-themes)
+                     (lambda () '(modus-vivendi tango)))
+                    ((symbol-function 'disable-theme)
+                     (lambda (theme) (push theme disabled)))
+                    ((symbol-function 'load-theme)
+                     (lambda (theme &optional _no-confirm _no-enable)
+                       (push theme loaded)
+                       ;; Pretend the load updated the enabled list so
+                       ;; `cj/get-active-theme-name' sees the new theme.
+                       (setq custom-enabled-themes (list theme))))
+                    ((symbol-function 'message) #'ignore))
+            (cj/switch-themes))
+          (should (equal disabled '(currently-on)))
+          (should (equal loaded '(modus-vivendi)))
+          (should (equal (cj/theme-read-file-contents file) "modus-vivendi")))
+      (delete-file file))))
+
+(provide 'test-ui-theme-commands)
+;;; test-ui-theme-commands.el ends here