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, 71 insertions, 0 deletions

diff --git a/tests/test-wttrin-mode-line-force-refresh.el b/tests/test-wttrin-mode-line-force-refresh.el
new file mode 100644
index 0000000..2275cee
--- /dev/null
+++ b/tests/test-wttrin-mode-line-force-refresh.el
@@ -0,0 +1,71 @@
+;;; test-wttrin-mode-line-force-refresh.el --- Tests for wttrin-mode-line-force-refresh -*- lexical-binding: t; -*-
+
+;; Copyright (C) 2025 Craig Jennings
+
+;;; Commentary:
+
+;; Unit tests for wttrin-mode-line-force-refresh function.
+;; Tests the right-click handler that force-refreshes mode-line weather.
+
+;;; Code:
+
+(require 'ert)
+(require 'wttrin)
+(require 'testutil-wttrin)
+
+;;; Setup and Teardown
+
+(defun test-wttrin-mode-line-force-refresh-setup ()
+  "Setup for mode-line-force-refresh tests."
+  (testutil-wttrin-setup)
+  (setq wttrin-mode-line-string nil)
+  (setq wttrin--mode-line-cache nil))
+
+(defun test-wttrin-mode-line-force-refresh-teardown ()
+  "Teardown for mode-line-force-refresh tests."
+  (testutil-wttrin-teardown)
+  (setq wttrin-mode-line-string nil)
+  (setq wttrin--mode-line-cache nil))
+
+;;; Normal Cases
+
+(ert-deftest test-wttrin-mode-line-force-refresh-normal-calls-fetch ()
+  "Right-click should trigger a weather fetch."
+  (test-wttrin-mode-line-force-refresh-setup)
+  (unwind-protect
+      (let ((wttrin-favorite-location "Paris")
+            (fetch-called nil))
+        (cl-letf (((symbol-function 'wttrin--mode-line-fetch-weather)
+                   (lambda () (setq fetch-called t))))
+          (wttrin-mode-line-force-refresh)
+          (should fetch-called)))
+    (test-wttrin-mode-line-force-refresh-teardown)))
+
+(ert-deftest test-wttrin-mode-line-force-refresh-normal-sets-force-flag ()
+  "The fetch should run with force-refresh bound to t to bypass cache."
+  (test-wttrin-mode-line-force-refresh-setup)
+  (unwind-protect
+      (let ((wttrin-favorite-location "Paris")
+            (force-flag-during-fetch nil))
+        (cl-letf (((symbol-function 'wttrin--mode-line-fetch-weather)
+                   (lambda () (setq force-flag-during-fetch wttrin--force-refresh))))
+          (wttrin-mode-line-force-refresh)
+          (should force-flag-during-fetch)))
+    (test-wttrin-mode-line-force-refresh-teardown)))
+
+;;; Boundary Cases
+
+(ert-deftest test-wttrin-mode-line-force-refresh-boundary-nil-location-is-noop ()
+  "When no favorite location is set, right-click should do nothing."
+  (test-wttrin-mode-line-force-refresh-setup)
+  (unwind-protect
+      (let ((wttrin-favorite-location nil)
+            (fetch-called nil))
+        (cl-letf (((symbol-function 'wttrin--mode-line-fetch-weather)
+                   (lambda () (setq fetch-called t))))
+          (wttrin-mode-line-force-refresh)
+          (should-not fetch-called)))
+    (test-wttrin-mode-line-force-refresh-teardown)))
+
+(provide 'test-wttrin-mode-line-force-refresh)
+;;; test-wttrin-mode-line-force-refresh.el ends here