#4 Added set of unit tests to ensure functionality of currently implemented behaviour

src/lib/api/weatherservice.test.ts

@@ -0,0 +1,29 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import { aviationWeatherApi } from './weatherservice';
+
+describe('aviationWeatherApi', () => {
+    beforeEach(() => {
+        vi.restoreAllMocks();
+    });
+
+    it('fetches METAR data successfully', async () => {
+        const mockMetar = { icaoId: 'EGKK', temp: 20 };
+        vi.stubGlobal('fetch', vi.fn().mockResolvedValue({
+            ok: true,
+            json: () => Promise.resolve(mockMetar)
+        }));
+
+        const result = await aviationWeatherApi.fetchMetar('EGKK');
+        expect(result).toEqual(mockMetar);
+        expect(fetch).toHaveBeenCalledWith('/api/metar/EGKK');
+    });
+
+    it('throws error if fetch fails', async () => {
+        vi.stubGlobal('fetch', vi.fn().mockResolvedValue({
+            ok: false,
+            statusText: 'Not Found'
+        }));
+
+        await expect(aviationWeatherApi.fetchMetar('XXXX')).rejects.toThrow('Failed to fetch METAR: Not Found');
+    });
+});