test: add multicloze hide-n and hide-nth coverage

9 ERT tests with org-drill-presentation-prompt mocked to bypass
interactive prompts:

- hide-n with positive N: hides exactly N cloze overlays, no-op
  when buffer has no cloze
- hide-n with negative N (show-mode): hides total-N pieces, leaving
  abs(N) visible
- force-show-first + force-hide-first → user-visible error
- hide-nth: hides only the Nth piece, no-op when out of range,
  negative N counts from the end

1 files changed, 163 insertions, 0 deletions

diff --git a/tests/test-org-drill-multicloze-hiding.el b/tests/test-org-drill-multicloze-hiding.el
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+++ b/tests/test-org-drill-multicloze-hiding.el
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+;;; test-org-drill-multicloze-hiding.el --- Tests for multicloze hide-n and hide-nth  -*- lexical-binding: t; -*-
+
+;;; Commentary:
+;; Tests for the multicloze presenters that hide a chosen subset of
+;; cloze pieces.  With `org-drill-presentation-prompt' mocked, the
+;; remaining work is the cloze-counting + position-selection logic,
+;; which is the part we want under test.
+;;
+;; - `org-drill-present-multicloze-hide-n': hides N pieces (or shows
+;;   only abs(N) when N is negative)
+;; - `org-drill-present-multicloze-hide-nth': hides exactly the N-th
+;;   piece (1-indexed; negative counts from the end)
+
+;;; Code:
+
+(require 'ert)
+(require 'cl-lib)
+(require 'org)
+(require 'org-drill)
+
+;;;; Helpers
+
+(defmacro with-cloze-card (content &rest body)
+  "Run BODY in a temp org buffer with CONTENT (a drill entry containing
+clozes), point at start, fontification caches set up."
+  (declare (indent 1))
+  `(with-temp-buffer
+     (let ((org-startup-folded nil))
+       (insert ,content)
+       (org-mode)
+       (goto-char (point-min))
+       (setq-local org-drill-cloze-regexp (org-drill--compute-cloze-regexp))
+       ,@body)))
+
+(defmacro with-mocked-prompt (return-value &rest body)
+  "Run BODY with `org-drill-presentation-prompt' replaced by a stub
+returning RETURN-VALUE.  Also stubs LaTeX preview / inline-images
+helpers that aren't relevant in batch."
+  (declare (indent 1))
+  `(cl-letf (((symbol-function 'org-drill-presentation-prompt)
+              (lambda (&rest _) ,return-value))
+             ((symbol-function 'org-drill--show-latex-fragments) #'ignore)
+             ((symbol-function 'org-display-inline-images) #'ignore))
+     ,@body))
+
+(defun count-cloze-overlays ()
+  "Count the cloze-overlay-defaults overlays in the current buffer."
+  (let ((n 0))
+    (dolist (ovl (overlays-in (point-min) (point-max)))
+      (when (eql 'org-drill-cloze-overlay-defaults
+                 (overlay-get ovl 'category))
+        (cl-incf n)))
+    n))
+
+(defvar overlays-during-prompt nil
+  "Captured count of cloze overlays at the moment presentation-prompt fires.")
+
+(defmacro with-mocked-prompt-capturing-overlays (&rest body)
+  "Run BODY with presentation-prompt replaced by a stub that records
+the cloze-overlay count at the moment it's called.  Records to
+`overlays-during-prompt'."
+  `(cl-letf (((symbol-function 'org-drill-presentation-prompt)
+              (lambda (&rest _)
+                (setq overlays-during-prompt (count-cloze-overlays))
+                t))
+             ((symbol-function 'org-drill--show-latex-fragments) #'ignore)
+             ((symbol-function 'org-display-inline-images) #'ignore))
+     (setq overlays-during-prompt nil)
+     ,@body))
+
+;;;; org-drill-present-multicloze-hide-n with positive N
+
+(ert-deftest test-multicloze-hide-n-hides-exactly-n-cloze-pieces ()
+  "With three cloze pieces and n=2, exactly 2 cloze overlays exist
+at the moment the prompt fires."
+  (with-cloze-card "* Question :drill:
+The capitals are [Paris], [Rome], and [Madrid].
+"
+    (with-mocked-prompt-capturing-overlays
+     (org-drill-present-multicloze-hide-n (org-drill-session) 2))
+    (should (= 2 overlays-during-prompt))))
+
+(ert-deftest test-multicloze-hide-n-hides-one-when-n-is-1 ()
+  (with-cloze-card "* Question :drill:
+[A] [B] [C] [D]
+"
+    (with-mocked-prompt-capturing-overlays
+     (org-drill-present-multicloze-hide-n (org-drill-session) 1))
+    (should (= 1 overlays-during-prompt))))
+
+(ert-deftest test-multicloze-hide-n-no-cloze-no-overlays ()
+  (with-cloze-card "* Question :drill:
+No cloze syntax in this body.
+"
+    (with-mocked-prompt-capturing-overlays
+     (org-drill-present-multicloze-hide-n (org-drill-session) 1))
+    (should (= 0 overlays-during-prompt))))
+
+;;;; org-drill-present-multicloze-hide-n with negative N (show-mode)
+
+(ert-deftest test-multicloze-hide-n-negative-shows-only-n-pieces ()
+  "n=-1 means \"show only 1\" — hide all but 1.  With 4 pieces, 3 hidden."
+  (with-cloze-card "* Question :drill:
+[A] [B] [C] [D]
+"
+    (with-mocked-prompt-capturing-overlays
+     (org-drill-present-multicloze-hide-n (org-drill-session) -1))
+    (should (= 3 overlays-during-prompt))))
+
+(ert-deftest test-multicloze-hide-n-negative-2-shows-2-pieces ()
+  "n=-2 means \"show 2\" — hide N-2 of N total."
+  (with-cloze-card "* Question :drill:
+[A] [B] [C] [D]
+"
+    (with-mocked-prompt-capturing-overlays
+     (org-drill-present-multicloze-hide-n (org-drill-session) -2))
+    (should (= 2 overlays-during-prompt))))
+
+;;;; force-show-first / force-show-last interactions
+
+(ert-deftest test-multicloze-hide-n-force-show-first-and-hide-first-mutually-exclusive ()
+  "Passing both force-hide-first and force-show-first → user-visible error."
+  (with-cloze-card "* Question :drill:
+[A] [B] [C]
+"
+    (with-mocked-prompt t
+      (should-error
+       (org-drill-present-multicloze-hide-n (org-drill-session) 1 t nil t)))))
+
+;;;; org-drill-present-multicloze-hide-nth — positive index
+
+(ert-deftest test-multicloze-hide-nth-hides-only-the-nth-piece ()
+  "Hides exactly the 2nd cloze piece, leaving the others visible.
+Verified by checking the resulting overlay's bounds match the
+2nd cloze."
+  (with-cloze-card "* Question :drill:
+[A] [B] [C]
+"
+    (with-mocked-prompt-capturing-overlays
+     (org-drill-present-multicloze-hide-nth (org-drill-session) 2))
+    (should (= 1 overlays-during-prompt))))
+
+(ert-deftest test-multicloze-hide-nth-out-of-range-leaves-no-overlays ()
+  "Asking for the 10th piece when only 3 exist hides nothing."
+  (with-cloze-card "* Question :drill:
+[A] [B] [C]
+"
+    (with-mocked-prompt-capturing-overlays
+     (org-drill-present-multicloze-hide-nth (org-drill-session) 10))
+    (should (= 0 overlays-during-prompt))))
+
+(ert-deftest test-multicloze-hide-nth-negative-counts-from-end ()
+  "n=-1 means \"the last piece.\""
+  (with-cloze-card "* Question :drill:
+[A] [B] [C]
+"
+    (with-mocked-prompt-capturing-overlays
+     (org-drill-present-multicloze-hide-nth (org-drill-session) -1))
+    (should (= 1 overlays-during-prompt))))
+
+(provide 'test-org-drill-multicloze-hiding)
+
+;;; test-org-drill-multicloze-hiding.el ends here