multimodel improvements

src/routes/weather/compare/[location]/comparison.spec.ts

@@ -0,0 +1,64 @@
+import { describe, expect, it } from 'vitest';
+
+import {
+	cardinalDirection,
+	isWindDirection,
+	modelColor,
+	modelMean,
+	sanitizeList,
+	validDirectionValues
+} from './comparison';
+
+import type { ModelSeriesData } from '$lib/services/weather';
+
+const models: ModelSeriesData[] = [
+	{
+		modelId: 'model-a',
+		resolvedModelId: 'model-a',
+		variables: {
+			precipitation: [1, Number.NaN, 3],
+			precipitation_probability: [80, 90, 100]
+		}
+	},
+	{
+		modelId: 'model-b',
+		resolvedModelId: 'model-b',
+		variables: { precipitation: [3, Number.NaN, 5] }
+	}
+];
+
+describe('multimodel comparison helpers', () => {
+	it('averages only the exact scalar variable and preserves missing values', () => {
+		expect(modelMean(models, 'precipitation', 3)).toEqual([2, null, 4]);
+	});
+
+	it('validates and deduplicates shared URL selections', () => {
+		const allowed = new Set(['a', 'b']);
+		expect(sanitizeList(['a', 'unknown', 'a', 'b'], allowed)).toEqual(['a', 'b']);
+		expect(sanitizeList(['unknown'], allowed)).toBeNull();
+	});
+
+	it('treats every wind direction height as a direction series', () => {
+		expect(isWindDirection('wind_direction_10m')).toBe(true);
+		expect(isWindDirection('wind_direction_180m')).toBe(true);
+		expect(isWindDirection('wind_speed_10m')).toBe(false);
+	});
+
+	it('drops direction values outside the fixed 0–360 degree domain', () => {
+		expect(validDirectionValues([-1, 0, 90, 360, 361, Number.NaN])).toEqual([
+			null,
+			0,
+			90,
+			360,
+			null,
+			null
+		]);
+		expect(cardinalDirection(0)).toBe('N');
+		expect(cardinalDirection(270)).toBe('W');
+	});
+
+	it('assigns deterministic model colors', () => {
+		expect(modelColor('ecmwf_ifs')).toBe(modelColor('ecmwf_ifs'));
+		expect(modelColor('ecmwf_ifs')).not.toBe(modelColor('gfs_global'));
+	});
+});