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, 91 insertions, 0 deletions

diff --git a/tests/test-wttrin-requery-force.el b/tests/test-wttrin-requery-force.el
new file mode 100644
index 0000000..04ad40a
--- /dev/null
+++ b/tests/test-wttrin-requery-force.el
@@ -0,0 +1,91 @@
+;;; test-wttrin-requery-force.el --- Tests for wttrin-requery-force -*- lexical-binding: t; -*-
+
+;; Copyright (C) 2025 Craig Jennings
+
+;;; Commentary:
+
+;; Unit tests for wttrin-requery-force function.
+;; Tests the force-refresh behavior that bypasses cache for the current location.
+
+;;; Code:
+
+(require 'ert)
+(require 'wttrin)
+(require 'testutil-wttrin)
+
+;;; Setup and Teardown
+
+(defun test-wttrin-requery-force-setup ()
+  "Setup for requery-force tests."
+  (testutil-wttrin-setup)
+  (when (get-buffer "*wttr.in*")
+    (kill-buffer "*wttr.in*")))
+
+(defun test-wttrin-requery-force-teardown ()
+  "Teardown for requery-force tests."
+  (testutil-wttrin-teardown)
+  (when (get-buffer "*wttr.in*")
+    (kill-buffer "*wttr.in*")))
+
+;;; Normal Cases
+
+(ert-deftest test-wttrin-requery-force-normal-queries-current-location ()
+  "Force refresh should query weather for the buffer's current location."
+  (test-wttrin-requery-force-setup)
+  (unwind-protect
+      (let ((queried-location nil))
+        (cl-letf (((symbol-function 'wttrin-query)
+                   (lambda (location) (setq queried-location location))))
+          ;; Set up a weather buffer with a known location
+          (with-current-buffer (get-buffer-create "*wttr.in*")
+            (setq-local wttrin--current-location "Berlin, DE")
+            (wttrin-requery-force)
+            (should (equal queried-location "Berlin, DE")))))
+    (test-wttrin-requery-force-teardown)))
+
+(ert-deftest test-wttrin-requery-force-normal-sets-force-refresh-flag ()
+  "The force-refresh flag should be true when the query executes."
+  (test-wttrin-requery-force-setup)
+  (unwind-protect
+      (let ((force-refresh-was-set nil))
+        (cl-letf (((symbol-function 'wttrin-query)
+                   (lambda (_location)
+                     (setq force-refresh-was-set wttrin--force-refresh))))
+          (with-current-buffer (get-buffer-create "*wttr.in*")
+            (setq-local wttrin--current-location "Paris")
+            (wttrin-requery-force)
+            (should force-refresh-was-set))))
+    (test-wttrin-requery-force-teardown)))
+
+;;; Boundary Cases
+
+(ert-deftest test-wttrin-requery-force-boundary-no-location-shows-message ()
+  "When no current location is set, user should be told there's nothing to refresh."
+  (test-wttrin-requery-force-setup)
+  (unwind-protect
+      (let ((displayed-message nil))
+        (cl-letf (((symbol-function 'message)
+                   (lambda (fmt &rest args)
+                     (setq displayed-message (apply #'format fmt args)))))
+          (with-current-buffer (get-buffer-create "*wttr.in*")
+            ;; wttrin--current-location is nil (buffer-local default)
+            (wttrin-requery-force)
+            (should displayed-message)
+            (should (string-match-p "No location" displayed-message)))))
+    (test-wttrin-requery-force-teardown)))
+
+(ert-deftest test-wttrin-requery-force-boundary-force-flag-does-not-leak ()
+  "The force-refresh flag should not persist after the requery completes."
+  (test-wttrin-requery-force-setup)
+  (unwind-protect
+      (progn
+        (cl-letf (((symbol-function 'wttrin-query) (lambda (_location) nil)))
+          (with-current-buffer (get-buffer-create "*wttr.in*")
+            (setq-local wttrin--current-location "Paris")
+            (wttrin-requery-force)))
+        ;; After the let-binding unwinds, force-refresh should be back to nil
+        (should-not wttrin--force-refresh))
+    (test-wttrin-requery-force-teardown)))
+
+(provide 'test-wttrin-requery-force)
+;;; test-wttrin-requery-force.el ends here