test: add gloss-drill test suite (red phase)

Four test files plus a small testutil for toggling the `org-drill'
feature flag. All 10 tests fail at this commit because the implementation
is still a stub.

The suite covers Normal (untagged entries get the tag and property),
Boundary (empty file, idempotency, untag never-tagged), and Error
(org-drill not installed). The error path also asserts the file is left
untouched. Untag-all is tested under both feature states because the
user might want to remove tags after uninstalling org-drill.

1 files changed, 60 insertions, 0 deletions

diff --git a/tests/test-gloss-drill--export-all-skips-already-tagged.el b/tests/test-gloss-drill--export-all-skips-already-tagged.el
new file mode 100644
index 0000000..52978c6
--- /dev/null
+++ b/tests/test-gloss-drill--export-all-skips-already-tagged.el
@@ -0,0 +1,60 @@
+;;; test-gloss-drill--export-all-skips-already-tagged.el --- Idempotency tests for gloss-drill-export-all -*- lexical-binding: t -*-
+
+;; SPDX-License-Identifier: GPL-3.0-or-later
+
+;;; Commentary:
+;; Tests for `gloss-drill-export-all' covering the Boundary case of
+;; running export twice in a row.  Running it on an already-tagged
+;; entry must not duplicate the :drill: tag, and the
+;; :DRILL_CARD_TYPE: twosided property must remain a single property
+;; with the same value.
+
+;;; Code:
+
+(require 'ert)
+(require 'gloss-drill)
+(require 'testutil-gloss)
+(require 'testutil-gloss-drill)
+
+(defun gloss-test--drill-tag-count-on-first-entry ()
+  "Return how many times \"drill\" appears in the first entry's tag list.
+Reads the file fresh from disk."
+  (with-current-buffer (find-file-noselect gloss-file)
+    (revert-buffer t t t)
+    (let ((count 0))
+      (org-map-entries
+       (lambda ()
+         (when (= 1 (org-current-level))
+           (setq count (length (cl-remove-if-not
+                                (lambda (tag) (equal tag "drill"))
+                                (org-get-tags nil t))))
+           (throw 'done nil))))
+      count)))
+
+(ert-deftest test-gloss-drill-export-all-idempotent-tag-not-duplicated ()
+  "Boundary: running export-all twice does not duplicate the :drill: tag."
+  (gloss-test--with-temp-glossary gloss-test--sample-content
+    (gloss-test--with-org-drill-feature
+      (gloss-drill-export-all)
+      (gloss-drill-export-all)
+      (catch 'done
+        (should (= (gloss-test--drill-tag-count-on-first-entry) 1))))))
+
+(ert-deftest test-gloss-drill-export-all-idempotent-property-unchanged ()
+  "Boundary: running export-all twice keeps :DRILL_CARD_TYPE: twosided."
+  (gloss-test--with-temp-glossary gloss-test--sample-content
+    (gloss-test--with-org-drill-feature
+      (gloss-drill-export-all)
+      (gloss-drill-export-all)
+      (with-current-buffer (find-file-noselect gloss-file)
+        (revert-buffer t t t)
+        (catch 'done
+          (org-map-entries
+           (lambda ()
+             (when (= 1 (org-current-level))
+               (should (equal (org-entry-get nil "DRILL_CARD_TYPE")
+                              "twosided"))
+               (throw 'done nil)))))))))
+
+(provide 'test-gloss-drill--export-all-skips-already-tagged)
+;;; test-gloss-drill--export-all-skips-already-tagged.el ends here