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, 245 insertions, 0 deletions

diff --git a/tests/test-chime-make-tooltip.el b/tests/test-chime-make-tooltip.el
new file mode 100644
index 0000000..f51a3b3
--- /dev/null
+++ b/tests/test-chime-make-tooltip.el
@@ -0,0 +1,245 @@
+;;; test-chime-make-tooltip.el --- Tests for tooltip generation functions -*- 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 tooltip generation functions:
+;; - chime--make-tooltip
+;; - chime--make-no-events-tooltip
+
+;;; 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 and Teardown
+
+(defun test-chime-make-tooltip-setup ()
+  "Setup function run before each test."
+  (chime-create-test-base-dir)
+  (setq chime-modeline-tooltip-max-events 5)
+  (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-make-tooltip-teardown ()
+  "Teardown function run after each test."
+  (chime-delete-test-base-dir))
+
+;;; Helper to build upcoming-events list items
+;;; Each item is (EVENT TIME-INFO MINUTES-UNTIL) where
+;;; TIME-INFO is (TIMESTAMP-STR . TIME-OBJECT)
+
+(defun test-make-upcoming-item (title time minutes-until)
+  "Create an upcoming-events list item for TITLE at TIME, MINUTES-UNTIL from now."
+  (let ((ts (test-timestamp-string time)))
+    (list `((title . ,title)
+            (times . ((,ts . ,time)))
+            (intervals . ((10 . medium))))
+          (cons ts time)
+          minutes-until)))
+
+;;;; Tests for chime--make-tooltip
+
+;;; Normal Cases
+
+(ert-deftest test-chime-make-tooltip-single-event ()
+  "Single event should produce tooltip with header, day label, and event line."
+  (test-chime-make-tooltip-setup)
+  (unwind-protect
+      (let* ((now (test-time-now))
+             (event-time (time-add now (seconds-to-time 1800))) ;; 30 min
+             (upcoming (list (test-make-upcoming-item "Team Meeting" event-time 30))))
+        (with-test-time now
+          (let ((result (chime--make-tooltip upcoming)))
+            (should (stringp result))
+            ;; Should contain header
+            (should (string-match-p "Upcoming Events" result))
+            ;; Should contain the event title
+            (should (string-match-p "Team Meeting" result))
+            ;; Should contain day separator
+            (should (string-match-p "─────────────" result)))))
+    (test-chime-make-tooltip-teardown)))
+
+(ert-deftest test-chime-make-tooltip-respects-max-events ()
+  "Should respect chime-modeline-tooltip-max-events limit."
+  (test-chime-make-tooltip-setup)
+  (unwind-protect
+      (let* ((now (test-time-now))
+             (upcoming (list
+                        (test-make-upcoming-item "Event 1" (time-add now (seconds-to-time 600)) 10)
+                        (test-make-upcoming-item "Event 2" (time-add now (seconds-to-time 1200)) 20)
+                        (test-make-upcoming-item "Event 3" (time-add now (seconds-to-time 1800)) 30)))
+             (chime-modeline-tooltip-max-events 2))
+        (with-test-time now
+          (let ((result (chime--make-tooltip upcoming)))
+            ;; Should show first 2 events
+            (should (string-match-p "Event 1" result))
+            (should (string-match-p "Event 2" result))
+            ;; Should NOT show 3rd event
+            (should-not (string-match-p "Event 3" result))
+            ;; Should show "and 1 more"
+            (should (string-match-p "1 more event" result)))))
+    (test-chime-make-tooltip-teardown)))
+
+(ert-deftest test-chime-make-tooltip-and-n-more-pluralized ()
+  "The 'and N more' text should use correct pluralization."
+  (test-chime-make-tooltip-setup)
+  (unwind-protect
+      (let* ((now (test-time-now))
+             (upcoming (list
+                        (test-make-upcoming-item "Event 1" (time-add now (seconds-to-time 600)) 10)
+                        (test-make-upcoming-item "Event 2" (time-add now (seconds-to-time 1200)) 20)
+                        (test-make-upcoming-item "Event 3" (time-add now (seconds-to-time 1800)) 30)
+                        (test-make-upcoming-item "Event 4" (time-add now (seconds-to-time 2400)) 40)))
+             (chime-modeline-tooltip-max-events 2))
+        (with-test-time now
+          (let ((result (chime--make-tooltip upcoming)))
+            ;; 2 remaining - should be "events" (plural)
+            (should (string-match-p "2 more events" result)))))
+    (test-chime-make-tooltip-teardown)))
+
+(ert-deftest test-chime-make-tooltip-nil-max-shows-all ()
+  "When chime-modeline-tooltip-max-events is nil, all events should be shown."
+  (test-chime-make-tooltip-setup)
+  (unwind-protect
+      (let* ((now (test-time-now))
+             (upcoming (list
+                        (test-make-upcoming-item "Event 1" (time-add now (seconds-to-time 600)) 10)
+                        (test-make-upcoming-item "Event 2" (time-add now (seconds-to-time 1200)) 20)
+                        (test-make-upcoming-item "Event 3" (time-add now (seconds-to-time 1800)) 30)))
+             (chime-modeline-tooltip-max-events nil))
+        (with-test-time now
+          (let ((result (chime--make-tooltip upcoming)))
+            (should (string-match-p "Event 1" result))
+            (should (string-match-p "Event 2" result))
+            (should (string-match-p "Event 3" result))
+            ;; No "more" text
+            (should-not (string-match-p "more event" result)))))
+    (test-chime-make-tooltip-teardown)))
+
+;;; Boundary Cases
+
+(ert-deftest test-chime-make-tooltip-empty-list-returns-nil ()
+  "Empty event list should return nil."
+  (should (null (chime--make-tooltip '()))))
+
+(ert-deftest test-chime-make-tooltip-nil-returns-nil ()
+  "Nil input should return nil."
+  (should (null (chime--make-tooltip nil))))
+
+(ert-deftest test-chime-make-tooltip-max-events-equals-count ()
+  "When max-events equals event count, no 'more' text should appear."
+  (test-chime-make-tooltip-setup)
+  (unwind-protect
+      (let* ((now (test-time-now))
+             (upcoming (list
+                        (test-make-upcoming-item "Event 1" (time-add now (seconds-to-time 600)) 10)
+                        (test-make-upcoming-item "Event 2" (time-add now (seconds-to-time 1200)) 20)))
+             (chime-modeline-tooltip-max-events 2))
+        (with-test-time now
+          (let ((result (chime--make-tooltip upcoming)))
+            (should (string-match-p "Event 1" result))
+            (should (string-match-p "Event 2" result))
+            (should-not (string-match-p "more event" result)))))
+    (test-chime-make-tooltip-teardown)))
+
+;;;; Tests for chime--make-no-events-tooltip
+
+;;; Normal Cases
+
+(ert-deftest test-chime-no-events-tooltip-shows-minutes ()
+  "For less than 60 minutes, should show timeframe in minutes."
+  (let ((result (chime--make-no-events-tooltip 30)))
+    (should (stringp result))
+    (should (string-match-p "30 minutes" result))
+    (should (string-match-p "Left-click: Open calendar" result))))
+
+(ert-deftest test-chime-no-events-tooltip-shows-hours ()
+  "For 2+ hours, should show timeframe in hours."
+  (let ((result (chime--make-no-events-tooltip 120)))
+    (should (stringp result))
+    (should (string-match-p "2 hours" result))))
+
+(ert-deftest test-chime-no-events-tooltip-shows-days ()
+  "For 7+ days, should show timeframe in days."
+  (let ((result (chime--make-no-events-tooltip 10080))) ;; 7 days
+    (should (stringp result))
+    (should (string-match-p "7 days" result))))
+
+(ert-deftest test-chime-no-events-tooltip-shows-fractional-days ()
+  "For 1-7 days (24-167 hours), should show fractional days."
+  (let ((result (chime--make-no-events-tooltip 2160))) ;; 36 hours = 1.5 days
+    (should (stringp result))
+    (should (string-match-p "1\\.5 days" result))))
+
+(ert-deftest test-chime-no-events-tooltip-includes-header ()
+  "Tooltip should include the header from chime-tooltip-header-format."
+  (let ((result (chime--make-no-events-tooltip 60)))
+    (should (string-match-p "Upcoming Events" result))))
+
+(ert-deftest test-chime-no-events-tooltip-mentions-config-var ()
+  "Tooltip should mention chime-tooltip-lookahead-hours for user guidance."
+  (let ((result (chime--make-no-events-tooltip 60)))
+    (should (string-match-p "chime-tooltip-lookahead-hours" result))))
+
+;;; Boundary Cases
+
+(ert-deftest test-chime-no-events-tooltip-exactly-60-minutes ()
+  "Exactly 60 minutes (1 hour) should say '1 hour' not '1 hours'."
+  (let ((result (chime--make-no-events-tooltip 60)))
+    (should (stringp result))
+    ;; A user expects correct English: "1 hour" not "1 hours"
+    (should (string-match-p "1 hour[^s]" result))))
+
+(ert-deftest test-chime-no-events-tooltip-exactly-1-day ()
+  "Exactly 1440 minutes (24 hours / 1 day) should not say '1.0 days'."
+  (let ((result (chime--make-no-events-tooltip 1440)))
+    (should (stringp result))
+    ;; User expects "1 day" or "1.0 day" — not "1.0 days"
+    (should (string-match-p "1\\.0 day[^s]" result))))
+
+(ert-deftest test-chime-no-events-tooltip-exactly-1-minute ()
+  "1 minute should say '1 minute' not '1 minutes'."
+  (let ((result (chime--make-no-events-tooltip 1)))
+    (should (stringp result))
+    ;; User expects "1 minute" not "1 minutes"
+    (should (string-match-p "1 minute[^s]" result))))
+
+(provide 'test-chime-make-tooltip)
+;;; test-chime-make-tooltip.el ends here