Add Daily recent changes comparison

internal/changes/daily_test.go

@@ -0,0 +1,123 @@
+package changes
+
+import (
+	"testing"
+	"time"
+
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/briefing"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/forecast"
+)
+
+func TestCompareDailyNoMeaningfulChanges(t *testing.T) {
+	previous := dailyBriefing(60, 70, 30, at("2026-05-29T08:00:00Z"), nil, forecast.Indicators{})
+	current := dailyBriefing(61, 71, 35, at("2026-05-29T08:30:00Z"), nil, forecast.Indicators{})
+
+	changes, err := CompareDaily(previous, current, testThresholds())
+	if err != nil {
+		t.Fatalf("CompareDaily() error = %v", err)
+	}
+	if len(changes) != 0 {
+		t.Fatalf("changes = %#v, want none", changes)
+	}
+}
+
+func TestCompareDailyTemperatureThreshold(t *testing.T) {
+	previous := dailyBriefing(50, 70, 10, at("2026-05-29T08:00:00Z"), nil, forecast.Indicators{})
+	current := dailyBriefing(58, 79, 10, at("2026-05-29T08:00:00Z"), nil, forecast.Indicators{})
+
+	changes, err := CompareDaily(previous, current, testThresholds())
+	if err != nil {
+		t.Fatalf("CompareDaily() error = %v", err)
+	}
+	if countType(changes, "temperature_shift") != 2 {
+		t.Fatalf("changes = %#v, want low and high temperature changes", changes)
+	}
+}
+
+func TestCompareDailyPrecipTimingShift(t *testing.T) {
+	previous := dailyBriefing(60, 70, 60, at("2026-05-29T08:00:00Z"), nil, forecast.Indicators{})
+	current := dailyBriefing(60, 70, 60, at("2026-05-29T11:00:00Z"), nil, forecast.Indicators{})
+
+	changes, err := CompareDaily(previous, current, testThresholds())
+	if err != nil {
+		t.Fatalf("CompareDaily() error = %v", err)
+	}
+	if countType(changes, "precip_timing_shift") != 1 {
+		t.Fatalf("changes = %#v, want timing shift", changes)
+	}
+}
+
+func TestCompareDailyAlertAddedAndRemoved(t *testing.T) {
+	previous := dailyBriefing(60, 70, 10, at("2026-05-29T08:00:00Z"), []string{"Wind Advisory"}, forecast.Indicators{})
+	current := dailyBriefing(60, 70, 10, at("2026-05-29T08:00:00Z"), []string{"Flood Watch"}, forecast.Indicators{})
+
+	changes, err := CompareDaily(previous, current, testThresholds())
+	if err != nil {
+		t.Fatalf("CompareDaily() error = %v", err)
+	}
+	if countType(changes, "alert_added") != 1 || countType(changes, "alert_removed") != 1 {
+		t.Fatalf("changes = %#v, want one alert added and one removed", changes)
+	}
+}
+
+func TestCompareDailyIndicatorChange(t *testing.T) {
+	previous := dailyBriefing(60, 70, 10, at("2026-05-29T08:00:00Z"), nil, forecast.Indicators{})
+	current := dailyBriefing(60, 70, 10, at("2026-05-29T08:00:00Z"), nil, forecast.Indicators{Thunder: true})
+
+	changes, err := CompareDaily(previous, current, testThresholds())
+	if err != nil {
+		t.Fatalf("CompareDaily() error = %v", err)
+	}
+	if countType(changes, "thunder_risk_change") != 1 {
+		t.Fatalf("changes = %#v, want thunder risk change", changes)
+	}
+}
+
+func dailyBriefing(low float64, high float64, precip float64, precipTime time.Time, alerts []string, indicators forecast.Indicators) briefing.Package {
+	alertOverlaps := make([]forecast.AlertOverlap, 0, len(alerts))
+	for _, alert := range alerts {
+		alertOverlaps = append(alertOverlaps, forecast.AlertOverlap{Event: alert})
+	}
+	return briefing.Package{
+		Daily: &briefing.Daily{
+			BottomLine: briefing.BottomLine{
+				Temperature: forecast.Range{Min: &low, Max: &high},
+				MaxPrecipProbability: &forecast.TimedValue{
+					Value: precip,
+					Time:  precipTime,
+				},
+			},
+			RelevantAlerts: alertOverlaps,
+			Dayparts: []forecast.DaypartSummary{
+				{Name: "morning", Indicators: indicators},
+			},
+		},
+	}
+}
+
+func testThresholds() Thresholds {
+	return Thresholds{
+		TemperatureDegrees:       5,
+		PrecipProbabilityPoints:  20,
+		WindGustMilesPerHour:     10,
+		PrecipTimingShiftMinutes: 120,
+	}
+}
+
+func countType(changes []Change, changeType string) int {
+	var count int
+	for _, change := range changes {
+		if change.Type == changeType {
+			count++
+		}
+	}
+	return count
+}
+
+func at(value string) time.Time {
+	parsed, err := time.Parse(time.RFC3339, value)
+	if err != nil {
+		panic(err)
+	}
+	return parsed
+}