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, 38 insertions, 0 deletions

diff --git a/tests/test-gloss-drill--export-all-no-orgdrill-installed.el b/tests/test-gloss-drill--export-all-no-orgdrill-installed.el
new file mode 100644
index 0000000..f8f4967
--- /dev/null
+++ b/tests/test-gloss-drill--export-all-no-orgdrill-installed.el
@@ -0,0 +1,38 @@
+;;; test-gloss-drill--export-all-no-orgdrill-installed.el --- Error tests for missing org-drill -*- lexical-binding: t -*-
+
+;; SPDX-License-Identifier: GPL-3.0-or-later
+
+;;; Commentary:
+;; Tests for `gloss-drill-export-all' covering the Error case where
+;; `org-drill' is not installed.  The function must raise `user-error'
+;; with an install hint and must not touch `gloss-file'.
+
+;;; Code:
+
+(require 'ert)
+(require 'gloss-drill)
+(require 'testutil-gloss)
+(require 'testutil-gloss-drill)
+
+(ert-deftest test-gloss-drill-export-all-without-org-drill-raises-user-error ()
+  "Error: missing `org-drill' raises `user-error' with an install hint."
+  (gloss-test--with-temp-glossary gloss-test--sample-content
+    (gloss-test--without-org-drill-feature
+      (let ((err (should-error (gloss-drill-export-all) :type 'user-error)))
+        (should (string-match-p "org-drill" (error-message-string err)))))))
+
+(ert-deftest test-gloss-drill-export-all-without-org-drill-leaves-file-untouched ()
+  "Error: missing `org-drill' must not modify the glossary file."
+  (gloss-test--with-temp-glossary gloss-test--sample-content
+    (gloss-test--without-org-drill-feature
+      (let ((before (with-temp-buffer
+                      (insert-file-contents gloss-file)
+                      (buffer-string))))
+        (ignore-errors (gloss-drill-export-all))
+        (let ((after (with-temp-buffer
+                       (insert-file-contents gloss-file)
+                       (buffer-string))))
+          (should (equal before after)))))))
+
+(provide 'test-gloss-drill--export-all-no-orgdrill-installed)
+;;; test-gloss-drill--export-all-no-orgdrill-installed.el ends here