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+;;; test-nov-reading--palette.el --- nov reading-palette tests -*- lexical-binding: t; -*-
+
+;;; Commentary:
+;; Pure-logic tests for the nov-mode reading-palette selector: name->face
+;; resolution and the cycle order (palettes, then the no-palette state, wrapping).
+;; The buffer-local face-remap application is exercised live, not here.
+
+;;; Code:
+
+(require 'ert)
+(require 'cl-lib)
+(add-to-list 'load-path (expand-file-name "modules" user-emacs-directory))
+(require 'nov-reading)
+
+(declare-function cj/nov--reading-palette-face "nov-reading" (name))
+(declare-function cj/nov--next-reading-palette "nov-reading" (current names))
+(defvar cj/nov-reading-palettes)
+
+;;; ----------------------- cj/nov--reading-palette-face -----------------------
+
+(ert-deftest test-nov-reading-palette-face-known ()
+  "Normal: a known palette name resolves to its face."
+  (let ((cj/nov-reading-palettes '(("sepia" . cj/nov-reading-sepia)
+                                   ("dark"  . cj/nov-reading-dark))))
+    (should (eq (cj/nov--reading-palette-face "sepia") 'cj/nov-reading-sepia))
+    (should (eq (cj/nov--reading-palette-face "dark") 'cj/nov-reading-dark))))
+
+(ert-deftest test-nov-reading-palette-face-unknown ()
+  "Error: an unknown name resolves to nil."
+  (let ((cj/nov-reading-palettes '(("sepia" . cj/nov-reading-sepia))))
+    (should-not (cj/nov--reading-palette-face "nope"))))
+
+(ert-deftest test-nov-reading-palette-face-nil ()
+  "Boundary: a nil name resolves to nil."
+  (let ((cj/nov-reading-palettes '(("sepia" . cj/nov-reading-sepia))))
+    (should-not (cj/nov--reading-palette-face nil))))
+
+;;; ----------------------- cj/nov--next-reading-palette -----------------------
+
+(ert-deftest test-nov-reading-next-palette-advances ()
+  "Normal: cycles to the next palette in order."
+  (should (equal (cj/nov--next-reading-palette "sepia" '("sepia" "dark" "light"))
+                 "dark")))
+
+(ert-deftest test-nov-reading-next-palette-last-to-none ()
+  "Boundary: the last palette cycles to the no-palette state (nil)."
+  (should-not (cj/nov--next-reading-palette "light" '("sepia" "dark" "light"))))
+
+(ert-deftest test-nov-reading-next-palette-none-to-first ()
+  "Boundary: the no-palette state (nil) cycles to the first palette."
+  (should (equal (cj/nov--next-reading-palette nil '("sepia" "dark" "light"))
+                 "sepia")))
+
+(ert-deftest test-nov-reading-next-palette-unknown-current-falls-to-first ()
+  "Error: an unknown current palette falls back to the first."
+  (should (equal (cj/nov--next-reading-palette "gone" '("sepia" "dark" "light"))
+                 "sepia")))
+
+(provide 'test-nov-reading--palette)
+;;; test-nov-reading--palette.el ends here