Add 94 tests across 10 new test files and fix 2 bugs

New test coverage for previously untested functions:
- filter-day-wide-events, time utilities, day-wide time matching
- make-tooltip, event-is-today, get-tags, done-keywords-predicate
- extract-title, propertize-modeline-string, warn-persistent-failures
- log-silently

Bug fixes discovered by new tests:
- Fix pluralization in no-events tooltip ("1 hours" -> "1 hour", etc.)
- Fix chime--get-tags returning ("") instead of nil for untagged headings

1 files changed, 163 insertions, 0 deletions

diff --git a/tests/test-chime-propertize-modeline.el b/tests/test-chime-propertize-modeline.el
new file mode 100644
index 0000000..fc210b2
--- /dev/null
+++ b/tests/test-chime-propertize-modeline.el
@@ -0,0 +1,163 @@
+;;; test-chime-propertize-modeline.el --- Tests for chime--propertize-modeline-string -*- lexical-binding: t; -*-
+
+;; Copyright (C) 2024-2026 Craig Jennings
+
+;; Author: Craig Jennings <c@cjennings.net>
+
+;; This program is free software: you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; This program is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;; Unit tests for chime--propertize-modeline-string function.
+;; This function adds tooltip, click handlers, and mouse-face to modeline text.
+
+;;; Code:
+
+;; Initialize package system for batch mode
+(when noninteractive
+  (package-initialize))
+
+(require 'ert)
+
+;; Load dependencies required by chime
+(require 'dash)
+(require 'alert)
+(require 'async)
+(require 'org-agenda)
+
+;; Load chime from parent directory
+(load (expand-file-name "../chime.el") nil t)
+
+;; Load test utilities
+(require 'testutil-general (expand-file-name "testutil-general.el"))
+(require 'testutil-time (expand-file-name "testutil-time.el"))
+(require 'testutil-events (expand-file-name "testutil-events.el"))
+
+;;; Setup/Teardown
+
+(defun test-chime-propertize-setup ()
+  "Setup function."
+  (chime-create-test-base-dir)
+  (setq chime-tooltip-header-format "Upcoming Events as of %a %b %d %Y @ %I:%M %p")
+  (setq chime-display-time-format-string "%I:%M %p")
+  (setq chime-time-left-format-at-event "right now")
+  (setq chime-time-left-format-short "in %M")
+  (setq chime-time-left-format-long "in %H %M"))
+
+(defun test-chime-propertize-teardown ()
+  "Teardown function."
+  (chime-delete-test-base-dir)
+  (setq chime--upcoming-events nil))
+
+;;; Normal Cases
+
+(ert-deftest test-chime-propertize-adds-help-echo ()
+  "Should add help-echo property (tooltip) when events exist."
+  (test-chime-propertize-setup)
+  (unwind-protect
+      (let* ((now (test-time-now))
+             (event-time (time-add now (seconds-to-time 1800)))
+             (ts (test-timestamp-string event-time)))
+        (setq chime--upcoming-events
+              (list (list `((title . "Meeting") (times . ((,ts . ,event-time))))
+                          (cons ts event-time)
+                          30)))
+        (with-test-time now
+          (let ((result (chime--propertize-modeline-string " ⏰ Meeting")))
+            (should (get-text-property 0 'help-echo result)))))
+    (test-chime-propertize-teardown)))
+
+(ert-deftest test-chime-propertize-adds-mouse-face ()
+  "Should add mouse-face property for highlight on hover."
+  (test-chime-propertize-setup)
+  (unwind-protect
+      (let* ((now (test-time-now))
+             (event-time (time-add now (seconds-to-time 1800)))
+             (ts (test-timestamp-string event-time)))
+        (setq chime--upcoming-events
+              (list (list `((title . "Meeting") (times . ((,ts . ,event-time))))
+                          (cons ts event-time)
+                          30)))
+        (with-test-time now
+          (let ((result (chime--propertize-modeline-string " ⏰ Meeting")))
+            (should (eq 'mode-line-highlight
+                        (get-text-property 0 'mouse-face result))))))
+    (test-chime-propertize-teardown)))
+
+(ert-deftest test-chime-propertize-adds-keymap ()
+  "Should add local-map with click handlers."
+  (test-chime-propertize-setup)
+  (unwind-protect
+      (let* ((now (test-time-now))
+             (event-time (time-add now (seconds-to-time 1800)))
+             (ts (test-timestamp-string event-time)))
+        (setq chime--upcoming-events
+              (list (list `((title . "Meeting") (times . ((,ts . ,event-time))))
+                          (cons ts event-time)
+                          30)))
+        (with-test-time now
+          (let ((result (chime--propertize-modeline-string " ⏰ Meeting")))
+            (should (keymapp (get-text-property 0 'local-map result))))))
+    (test-chime-propertize-teardown)))
+
+(ert-deftest test-chime-propertize-tooltip-contains-event ()
+  "Tooltip text should contain the event title."
+  (test-chime-propertize-setup)
+  (unwind-protect
+      (let* ((now (test-time-now))
+             (event-time (time-add now (seconds-to-time 1800)))
+             (ts (test-timestamp-string event-time)))
+        (setq chime--upcoming-events
+              (list (list `((title . "Team Standup") (times . ((,ts . ,event-time))))
+                          (cons ts event-time)
+                          30)))
+        (with-test-time now
+          (let* ((result (chime--propertize-modeline-string " ⏰ Meeting"))
+                 (tooltip (get-text-property 0 'help-echo result)))
+            (should (string-match-p "Team Standup" tooltip)))))
+    (test-chime-propertize-teardown)))
+
+;;; Boundary Cases
+
+(ert-deftest test-chime-propertize-nil-events-returns-plain-text ()
+  "When chime--upcoming-events is nil, should return plain text without properties."
+  (test-chime-propertize-setup)
+  (unwind-protect
+      (let ((chime--upcoming-events nil))
+        (let ((result (chime--propertize-modeline-string " ⏰")))
+          ;; Should return the text as-is
+          (should (string= " ⏰" result))
+          ;; Should NOT have help-echo (no tooltip)
+          (should-not (get-text-property 0 'help-echo result))))
+    (test-chime-propertize-teardown)))
+
+(ert-deftest test-chime-propertize-empty-text ()
+  "Empty string should still get properties when events exist."
+  (test-chime-propertize-setup)
+  (unwind-protect
+      (let* ((now (test-time-now))
+             (event-time (time-add now (seconds-to-time 1800)))
+             (ts (test-timestamp-string event-time)))
+        (setq chime--upcoming-events
+              (list (list `((title . "Meeting") (times . ((,ts . ,event-time))))
+                          (cons ts event-time)
+                          30)))
+        (with-test-time now
+          (let ((result (chime--propertize-modeline-string "")))
+            ;; Even empty string gets propertized
+            (should (stringp result)))))
+    (test-chime-propertize-teardown)))
+
+(provide 'test-chime-propertize-modeline)
+;;; test-chime-propertize-modeline.el ends here