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, 104 insertions, 0 deletions

diff --git a/tests/test-wttrin--mode-line-stop.el b/tests/test-wttrin--mode-line-stop.el
new file mode 100644
index 0000000..e791ee5
--- /dev/null
+++ b/tests/test-wttrin--mode-line-stop.el
@@ -0,0 +1,104 @@
+;;; test-wttrin--mode-line-stop.el --- Tests for wttrin--mode-line-stop -*- lexical-binding: t; -*-
+
+;; Copyright (C) 2025 Craig Jennings
+
+;;; Commentary:
+
+;; Unit tests for wttrin--mode-line-stop function.
+;; Tests that stopping mode-line display cleans up all state properly.
+
+;;; Code:
+
+(require 'ert)
+(require 'wttrin)
+(require 'testutil-wttrin)
+
+;;; Setup and Teardown
+
+(defun test-wttrin--mode-line-stop-setup ()
+  "Setup for mode-line-stop 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-stop-teardown ()
+  "Teardown for mode-line-stop tests."
+  (testutil-wttrin-teardown)
+  ;; Cancel any real timers that may have been created
+  (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-stop-normal-clears-mode-line-string ()
+  "After stop, mode-line-string should be nil so nothing shows in the mode-line."
+  (test-wttrin--mode-line-stop-setup)
+  (unwind-protect
+      (progn
+        (setq wttrin-mode-line-string "some weather display")
+        (wttrin--mode-line-stop)
+        (should-not wttrin-mode-line-string))
+    (test-wttrin--mode-line-stop-teardown)))
+
+(ert-deftest test-wttrin--mode-line-stop-normal-clears-mode-line-cache ()
+  "After stop, cached mode-line data should be discarded."
+  (test-wttrin--mode-line-stop-setup)
+  (unwind-protect
+      (progn
+        (setq wttrin--mode-line-cache (cons (float-time) "Paris: ☀️ +61°F Clear"))
+        (wttrin--mode-line-stop)
+        (should-not wttrin--mode-line-cache))
+    (test-wttrin--mode-line-stop-teardown)))
+
+(ert-deftest test-wttrin--mode-line-stop-normal-cancels-mode-line-timer ()
+  "After stop, the mode-line refresh timer should be cancelled and nil."
+  (test-wttrin--mode-line-stop-setup)
+  (unwind-protect
+      (progn
+        ;; Create a real timer so cancel-timer has something to work with
+        (setq wttrin--mode-line-timer
+              (run-at-time 99999 nil #'ignore))
+        (wttrin--mode-line-stop)
+        (should-not wttrin--mode-line-timer))
+    (test-wttrin--mode-line-stop-teardown)))
+
+(ert-deftest test-wttrin--mode-line-stop-normal-cancels-buffer-refresh-timer ()
+  "After stop, the buffer-refresh timer should be cancelled and nil."
+  (test-wttrin--mode-line-stop-setup)
+  (unwind-protect
+      (progn
+        (setq wttrin--buffer-refresh-timer
+              (run-at-time 99999 nil #'ignore))
+        (wttrin--mode-line-stop)
+        (should-not wttrin--buffer-refresh-timer))
+    (test-wttrin--mode-line-stop-teardown)))
+
+;;; Boundary Cases
+
+(ert-deftest test-wttrin--mode-line-stop-boundary-safe-when-already-stopped ()
+  "Calling stop when everything is already nil should not error."
+  (test-wttrin--mode-line-stop-setup)
+  (unwind-protect
+      (progn
+        ;; Everything is already nil from setup
+        (should-not wttrin--mode-line-timer)
+        (should-not wttrin--buffer-refresh-timer)
+        (should-not wttrin-mode-line-string)
+        (should-not wttrin--mode-line-cache)
+        ;; This should not error
+        (wttrin--mode-line-stop)
+        ;; Still nil
+        (should-not wttrin--mode-line-timer)
+        (should-not wttrin-mode-line-string))
+    (test-wttrin--mode-line-stop-teardown)))
+
+(provide 'test-wttrin--mode-line-stop)
+;;; test-wttrin--mode-line-stop.el ends here