fix: close drill capture template source link

The "d" drill capture template had a malformed source link with only one closing bracket and a literal `n` where a newline should have been:

    Source: [[%:link][%:description]
    nCaptured On: %U

So new drill captures wrote a broken link and `nCaptured On:` instead of a clean `Captured On:` line on the next row.

I closed the link with the missing `]`, and removed the stray `n` so the line break before "Captured On" is just a real newline. The "f" (PDF drill) template was already correct, so I left it alone.

I added `tests/test-org-capture-config-drill-template.el`. It loads the module, picks up the "d" template, and asserts both the closed link and the `\nCaptured On: %U` form, plus negative assertions against the broken pre-fix shapes.

2 files changed, 28 insertions, 2 deletions

diff --git a/modules/org-capture-config.el b/modules/org-capture-config.el
index 755eecaf..c20504f0 100644
--- a/modules/org-capture-config.el
+++ b/modules/org-capture-config.el
@@ -130,8 +130,8 @@ Captured On: %U"
                       (completing-read "Choose file: " files)
                       drill-dir))))
            "* Item   :drill:\n%?
-** Answer\n%i\nSource: [[%:link][%:description]
-nCaptured On: %U" :prepend t)
+** Answer\n%i\nSource: [[%:link][%:description]]
+Captured On: %U" :prepend t)
 
           ("f" "Drill Question (from PDF)" entry
            (file (lambda ()
diff --git a/tests/test-org-capture-config-drill-template.el b/tests/test-org-capture-config-drill-template.el
new file mode 100644
index 00000000..8f13dbe9
--- /dev/null
+++ b/tests/test-org-capture-config-drill-template.el
@@ -0,0 +1,26 @@
+;;; test-org-capture-config-drill-template.el --- Tests for drill capture templates -*- lexical-binding: t; -*-
+
+;;; Commentary:
+;; Verifies the drill org-capture template remains well-formed.
+
+;;; Code:
+
+(require 'ert)
+(require 'org)
+
+(add-to-list 'load-path (expand-file-name "modules" user-emacs-directory))
+(require 'org-capture-config)
+
+(ert-deftest test-org-capture-config-drill-template-source-link-is-closed ()
+  "The regular drill capture template should emit a valid source link."
+  (let ((template (nth 4 (assoc "d" org-capture-templates))))
+    (should (stringp template))
+    (should (string-match-p
+             "Source: \\[\\[%:link\\]\\[%:description\\]\\]"
+             template))
+    (should (string-match-p "\nCaptured On: %U" template))
+    (should-not (string-match-p "\\[%:description\\]\n" template))
+    (should-not (string-match-p "\nnCaptured On: %U" template))))
+
+(provide 'test-org-capture-config-drill-template)
+;;; test-org-capture-config-drill-template.el ends here