feat(mode-line): optional multi-day forecast in the weather tooltip

The tooltip showed current conditions only. I added wttrin-mode-line-tooltip-forecast-days (default 0, capped at wttr.in's three days). When positive, the mode-line refresh also fetches ?format=j1 and caches the parsed day list, and the tooltip renders one line per day between the conditions and the age line: Today / Tomorrow / weekday label, min-max temps in the configured unit, and the midday description. A failed or malformed forecast fetch keeps the previous forecast and never disturbs the main fetch.

1 files changed, 149 insertions, 0 deletions

diff --git a/tests/test-wttrin--mode-line-forecast.el b/tests/test-wttrin--mode-line-forecast.el
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+++ b/tests/test-wttrin--mode-line-forecast.el
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+;;; test-wttrin--mode-line-forecast.el --- Tests for the tooltip forecast -*- lexical-binding: t; -*-
+
+;; Copyright (C) 2026 Craig Jennings
+
+;;; Commentary:
+
+;; Unit tests for the mode-line tooltip forecast: parsing wttr.in's j1 JSON
+;; into a day list, formatting up to `wttrin-mode-line-tooltip-forecast-days'
+;; lines, and appending the block to `wttrin--mode-line-tooltip' output.
+
+;;; Code:
+
+(require 'ert)
+(require 'wttrin)
+(require 'testutil-wttrin)
+
+;;; Fixture
+
+(defconst test-wttrin--forecast-j1
+  "{\"weather\": [
+     {\"date\": \"2026-07-01\", \"mintempC\": \"22\", \"maxtempC\": \"31\",
+      \"mintempF\": \"71\", \"maxtempF\": \"88\",
+      \"hourly\": [{\"time\": \"0\", \"weatherDesc\": [{\"value\": \"Clear\"}]},
+                   {\"time\": \"1200\", \"weatherDesc\": [{\"value\": \"Partly cloudy\"}]},
+                   {\"time\": \"2100\", \"weatherDesc\": [{\"value\": \"Clear\"}]}]},
+     {\"date\": \"2026-07-02\", \"mintempC\": \"20\", \"maxtempC\": \"26\",
+      \"mintempF\": \"68\", \"maxtempF\": \"79\",
+      \"hourly\": [{\"time\": \"1200\", \"weatherDesc\": [{\"value\": \"Light rain\"}]}]},
+     {\"date\": \"2026-07-03\", \"mintempC\": \"21\", \"maxtempC\": \"31\",
+      \"mintempF\": \"70\", \"maxtempF\": \"88\",
+      \"hourly\": [{\"time\": \"1200\", \"weatherDesc\": [{\"value\": \"Sunny\"}]}]}]}"
+  "Trimmed wttr.in ?format=j1 response: three days, the keys the code reads.")
+
+(defun test-wttrin--forecast-days ()
+  "Return the parsed day list from the fixture."
+  (wttrin--forecast-parse test-wttrin--forecast-j1))
+
+;;; --------------------------------------------------------------------------
+;;; wttrin--forecast-parse
+;;; --------------------------------------------------------------------------
+
+(ert-deftest test-wttrin--forecast-parse-normal-three-days ()
+  "Normal: the fixture parses into a list of three day alists."
+  (let ((days (test-wttrin--forecast-days)))
+    (should (= 3 (length days)))
+    (should (equal "2026-07-01" (alist-get 'date (car days))))))
+
+(ert-deftest test-wttrin--forecast-parse-error-malformed-json ()
+  "Error: malformed JSON returns nil instead of signaling."
+  (should-not (wttrin--forecast-parse "{not json")))
+
+(ert-deftest test-wttrin--forecast-parse-error-missing-weather-key ()
+  "Error: JSON without a weather array returns nil."
+  (should-not (wttrin--forecast-parse "{\"nearest_area\": []}")))
+
+(ert-deftest test-wttrin--forecast-parse-boundary-nil-and-empty ()
+  "Boundary: nil and empty-string input return nil."
+  (should-not (wttrin--forecast-parse nil))
+  (should-not (wttrin--forecast-parse "")))
+
+;;; --------------------------------------------------------------------------
+;;; wttrin--forecast-format
+;;; --------------------------------------------------------------------------
+
+(ert-deftest test-wttrin--forecast-format-normal-three-days-fahrenheit ()
+  "Normal: unit system \"u\" renders three labeled lines with °F ranges."
+  (let* ((wttrin-unit-system "u")
+         (text (wttrin--forecast-format (test-wttrin--forecast-days) 3))
+         (lines (split-string text "\n")))
+    (should (= 3 (length lines)))
+    (should (string-match-p "\\`Today 71-88°F Partly cloudy\\'" (nth 0 lines)))
+    (should (string-match-p "\\`Tomorrow 68-79°F Light rain\\'" (nth 1 lines)))
+    ;; 2026-07-03 is a Friday; the third day is labeled by weekday.
+    (should (string-match-p "\\`Fri 70-88°F Sunny\\'" (nth 2 lines)))))
+
+(ert-deftest test-wttrin--forecast-format-normal-metric ()
+  "Normal: a non-\"u\" unit system renders °C ranges."
+  (let* ((wttrin-unit-system "m")
+         (text (wttrin--forecast-format (test-wttrin--forecast-days) 2)))
+    (should (string-match-p "Today 22-31°C" text))
+    (should (string-match-p "Tomorrow 20-26°C" text))))
+
+(ert-deftest test-wttrin--forecast-format-boundary-day-counts ()
+  "Boundary: 0 days is nil; 1 day is one line; >3 caps at the data."
+  (let ((wttrin-unit-system "u")
+        (days (test-wttrin--forecast-days)))
+    (should-not (wttrin--forecast-format days 0))
+    (should (= 1 (length (split-string (wttrin--forecast-format days 1) "\n"))))
+    (should (= 3 (length (split-string (wttrin--forecast-format days 5) "\n"))))))
+
+(ert-deftest test-wttrin--forecast-format-boundary-missing-hourly-desc ()
+  "Boundary: a day with no hourly data renders the temps without a description."
+  (let* ((wttrin-unit-system "u")
+         (day '((date . "2026-07-01") (mintempF . "71") (maxtempF . "88")
+                (mintempC . "22") (maxtempC . "31") (hourly . ())))
+         (text (wttrin--forecast-format (list day) 1)))
+    (should (equal "Today 71-88°F" text))))
+
+(ert-deftest test-wttrin--forecast-format-error-nil-days ()
+  "Error: nil day list returns nil."
+  (should-not (wttrin--forecast-format nil 3)))
+
+;;; --------------------------------------------------------------------------
+;;; tooltip integration
+;;; --------------------------------------------------------------------------
+
+(defun test-wttrin--forecast-tooltip-fixture (option-days)
+  "Return the tooltip with fresh current + forecast caches and OPTION-DAYS."
+  (let ((wttrin-unit-system "u")
+        (wttrin-mode-line-tooltip-forecast-days option-days)
+        (wttrin--mode-line-cache (cons (float-time) "Paris: ☀️ +61°F Clear"))
+        (wttrin--mode-line-forecast-cache
+         (cons (float-time) (test-wttrin--forecast-days))))
+    (wttrin--mode-line-tooltip)))
+
+(ert-deftest test-wttrin--forecast-tooltip-normal-appends-block ()
+  "Normal: with the option at 3, the tooltip carries the forecast lines."
+  (testutil-wttrin-setup)
+  (unwind-protect
+      (let ((tooltip (test-wttrin--forecast-tooltip-fixture 3)))
+        (should (string-match-p "Paris" tooltip))
+        (should (string-match-p "Today 71-88°F Partly cloudy" tooltip))
+        (should (string-match-p "Fri 70-88°F Sunny" tooltip))
+        (should (string-match-p "Updated" tooltip)))
+    (testutil-wttrin-teardown)))
+
+(ert-deftest test-wttrin--forecast-tooltip-boundary-option-zero-unchanged ()
+  "Boundary: with the option at 0 (default), the tooltip has no forecast."
+  (testutil-wttrin-setup)
+  (unwind-protect
+      (let ((tooltip (test-wttrin--forecast-tooltip-fixture 0)))
+        (should (string-match-p "Paris" tooltip))
+        (should-not (string-match-p "Today" tooltip)))
+    (testutil-wttrin-teardown)))
+
+(ert-deftest test-wttrin--forecast-tooltip-boundary-empty-forecast-cache ()
+  "Boundary: option on but no forecast cache yet leaves the tooltip as before."
+  (testutil-wttrin-setup)
+  (unwind-protect
+      (let ((wttrin-mode-line-tooltip-forecast-days 3)
+            (wttrin--mode-line-cache (cons (float-time) "Paris: ☀️ +61°F Clear"))
+            (wttrin--mode-line-forecast-cache nil))
+        (let ((tooltip (wttrin--mode-line-tooltip)))
+          (should (string-match-p "Paris" tooltip))
+          (should-not (string-match-p "Today" tooltip))))
+    (testutil-wttrin-teardown)))
+
+(provide 'test-wttrin--mode-line-forecast)
+;;; test-wttrin--mode-line-forecast.el ends here