test: add 50 tests for untested functions; fix nil crash in save-debug-data

Add 11 new test files covering wttrin--save-debug-data,
wttrin--buffer-cache-refresh, wttrin--mode-line-stop,
wttrin--mode-line-start, wttrin-query, wttrin-requery-force,
wttrin-mode-line-click, wttrin-mode-line-force-refresh,
wttrin-fetch-raw-string, wttrin-clear-cache, and wttrin-requery.

Fix bug in wttrin--save-debug-data where nil raw-string caused
(insert nil) crash — reachable when debug mode is on and fetch fails.

Refactor wttrin-requery: extract wttrin--requery-location so the
core kill-buffer-and-query logic is testable without mocking
completing-read.

267 tests total (was 217), all passing.

1 files changed, 157 insertions, 0 deletions

diff --git a/tests/test-wttrin--mode-line-start.el b/tests/test-wttrin--mode-line-start.el
new file mode 100644
index 0000000..e97c185
--- /dev/null
+++ b/tests/test-wttrin--mode-line-start.el
@@ -0,0 +1,157 @@
+;;; test-wttrin--mode-line-start.el --- Tests for wttrin--mode-line-start -*- lexical-binding: t; -*-
+
+;; Copyright (C) 2025 Craig Jennings
+
+;;; Commentary:
+
+;; Unit tests for wttrin--mode-line-start function.
+;; Tests that starting mode-line display sets up placeholder, timers, and scheduling.
+
+;;; Code:
+
+(require 'ert)
+(require 'wttrin)
+(require 'testutil-wttrin)
+
+;;; Setup and Teardown
+
+(defun test-wttrin--mode-line-start-setup ()
+  "Setup for mode-line-start tests."
+  (testutil-wttrin-setup)
+  (setq wttrin-mode-line-string nil)
+  (setq wttrin--mode-line-cache nil)
+  (setq wttrin--mode-line-timer nil)
+  (setq wttrin--buffer-refresh-timer nil))
+
+(defun test-wttrin--mode-line-start-teardown ()
+  "Teardown for mode-line-start tests."
+  (testutil-wttrin-teardown)
+  (when (timerp wttrin--mode-line-timer)
+    (cancel-timer wttrin--mode-line-timer))
+  (when (timerp wttrin--buffer-refresh-timer)
+    (cancel-timer wttrin--buffer-refresh-timer))
+  (setq wttrin-mode-line-string nil)
+  (setq wttrin--mode-line-cache nil)
+  (setq wttrin--mode-line-timer nil)
+  (setq wttrin--buffer-refresh-timer nil))
+
+;;; Normal Cases
+
+(ert-deftest test-wttrin--mode-line-start-normal-shows-placeholder-immediately ()
+  "Starting mode-line should show the hourglass placeholder right away."
+  (test-wttrin--mode-line-start-setup)
+  (unwind-protect
+      (let ((wttrin-favorite-location "Paris")
+            (wttrin-mode-line-emoji-font nil))
+        ;; Mock run-at-time so no real timers fire
+        (cl-letf (((symbol-function 'run-at-time)
+                   (lambda (_time _repeat _func) (list 'mock-timer))))
+          (wttrin--mode-line-start)
+          ;; Placeholder should be visible
+          (should wttrin-mode-line-string)
+          (should (string-match-p "⏳" (substring-no-properties wttrin-mode-line-string)))))
+    (test-wttrin--mode-line-start-teardown)))
+
+(ert-deftest test-wttrin--mode-line-start-normal-schedules-delayed-initial-fetch ()
+  "Initial weather fetch should be scheduled after startup-delay seconds."
+  (test-wttrin--mode-line-start-setup)
+  (unwind-protect
+      (let ((wttrin-favorite-location "Paris")
+            (wttrin-mode-line-startup-delay 5)
+            (scheduled-calls nil))
+        (cl-letf (((symbol-function 'run-at-time)
+                   (lambda (time repeat func)
+                     (push (list :time time :repeat repeat :func func) scheduled-calls)
+                     (list 'mock-timer))))
+          (wttrin--mode-line-start)
+          ;; One of the calls should be the delayed initial fetch
+          (let ((initial-fetch (seq-find (lambda (call)
+                                           (and (= (plist-get call :time) 5)
+                                                (null (plist-get call :repeat))))
+                                         scheduled-calls)))
+            (should initial-fetch)
+            (should (eq (plist-get initial-fetch :func)
+                        #'wttrin--mode-line-fetch-weather)))))
+    (test-wttrin--mode-line-start-teardown)))
+
+(ert-deftest test-wttrin--mode-line-start-normal-creates-repeating-mode-line-timer ()
+  "A repeating timer should be created for periodic mode-line refresh."
+  (test-wttrin--mode-line-start-setup)
+  (unwind-protect
+      (let ((wttrin-favorite-location "Paris")
+            (wttrin-mode-line-refresh-interval 3600)
+            (scheduled-calls nil))
+        (cl-letf (((symbol-function 'run-at-time)
+                   (lambda (time repeat func)
+                     (push (list :time time :repeat repeat :func func) scheduled-calls)
+                     (list 'mock-timer))))
+          (wttrin--mode-line-start)
+          ;; Should have a repeating timer for mode-line fetch
+          (let ((repeating-fetch (seq-find (lambda (call)
+                                             (and (equal (plist-get call :repeat) 3600)
+                                                  (eq (plist-get call :func)
+                                                      #'wttrin--mode-line-fetch-weather)))
+                                           scheduled-calls)))
+            (should repeating-fetch))))
+    (test-wttrin--mode-line-start-teardown)))
+
+(ert-deftest test-wttrin--mode-line-start-normal-creates-buffer-refresh-timer ()
+  "A repeating timer should be created for periodic buffer cache refresh."
+  (test-wttrin--mode-line-start-setup)
+  (unwind-protect
+      (let ((wttrin-favorite-location "Paris")
+            (wttrin-refresh-interval 3600)
+            (scheduled-calls nil))
+        (cl-letf (((symbol-function 'run-at-time)
+                   (lambda (time repeat func)
+                     (push (list :time time :repeat repeat :func func) scheduled-calls)
+                     (list 'mock-timer))))
+          (wttrin--mode-line-start)
+          ;; Should have a repeating timer for buffer cache refresh
+          (let ((buffer-refresh (seq-find (lambda (call)
+                                            (and (equal (plist-get call :repeat) 3600)
+                                                 (eq (plist-get call :func)
+                                                     #'wttrin--buffer-cache-refresh)))
+                                          scheduled-calls)))
+            (should buffer-refresh))))
+    (test-wttrin--mode-line-start-teardown)))
+
+;;; Boundary Cases
+
+(ert-deftest test-wttrin--mode-line-start-boundary-nil-location-skips-setup ()
+  "When no favorite location is set, no timers or placeholder should be created."
+  (test-wttrin--mode-line-start-setup)
+  (unwind-protect
+      (let ((wttrin-favorite-location nil)
+            (run-at-time-called nil))
+        (cl-letf (((symbol-function 'run-at-time)
+                   (lambda (_time _repeat _func)
+                     (setq run-at-time-called t)
+                     (list 'mock-timer))))
+          (wttrin--mode-line-start)
+          (should-not run-at-time-called)
+          (should-not wttrin-mode-line-string)
+          (should-not wttrin--mode-line-timer)))
+    (test-wttrin--mode-line-start-teardown)))
+
+(ert-deftest test-wttrin--mode-line-start-boundary-cancels-existing-timers ()
+  "Starting when timers already exist should cancel old timers before creating new ones."
+  (test-wttrin--mode-line-start-setup)
+  (unwind-protect
+      (let ((wttrin-favorite-location "Paris")
+            (cancelled-timers nil))
+        ;; Create fake existing timers
+        (setq wttrin--mode-line-timer (run-at-time 99999 nil #'ignore))
+        (setq wttrin--buffer-refresh-timer (run-at-time 99999 nil #'ignore))
+        (let ((old-ml-timer wttrin--mode-line-timer)
+              (old-buf-timer wttrin--buffer-refresh-timer))
+          (cl-letf (((symbol-function 'run-at-time)
+                     (lambda (_time _repeat _func) (list 'mock-timer))))
+            (wttrin--mode-line-start)
+            ;; Old timers should have been replaced
+            (should-not (eq wttrin--mode-line-timer old-ml-timer))
+            (should-not (eq wttrin--buffer-refresh-timer old-buf-timer)))))
+    (test-wttrin--mode-line-start-teardown)))
+
+(provide 'test-wttrin--mode-line-start)
+;;; test-wttrin--mode-line-start.el ends here