Initial commit

frontend/tests/api.test.ts

@@ -0,0 +1,80 @@
+import { afterEach, describe, expect, it, vi } from 'vitest'
+import { ApiError, apiFetch } from '../src/api/client'
+
+/* fetch is stubbed with Response-shaped objects — the client only needs
+   status/ok/json, and this keeps the test independent of jsdom's fetch. */
+
+function stubFetch(body: unknown, status = 200) {
+  const mock = vi.fn().mockResolvedValue({
+    status,
+    ok: status >= 200 && status < 300,
+    statusText: 'status text',
+    json: () => Promise.resolve(body),
+  })
+  vi.stubGlobal('fetch', mock)
+  return mock
+}
+
+afterEach(() => {
+  vi.unstubAllGlobals()
+})
+
+describe('apiFetch', () => {
+  it('decodes a JSON response', async () => {
+    stubFetch([{ id: 1, title: 'First' }])
+
+    await expect(apiFetch('/api/v1/items')).resolves.toEqual([{ id: 1, title: 'First' }])
+  })
+
+  it('sends method, JSON headers and a JSON body', async () => {
+    const mock = stubFetch({ id: 1 })
+
+    await apiFetch('/api/v1/items', { method: 'POST', body: JSON.stringify({ title: 'x' }) })
+
+    const [path, init] = mock.mock.calls[0]! as [string, RequestInit]
+    expect(path).toBe('/api/v1/items')
+    expect(init.method).toBe('POST')
+    expect(init.body).toBe(JSON.stringify({ title: 'x' }))
+    expect(init.headers).toMatchObject({ 'Content-Type': 'application/json' })
+  })
+
+  it('returns undefined for 204 responses', async () => {
+    stubFetch(null, 204)
+
+    await expect(apiFetch<void>('/api/v1/items/1', { method: 'DELETE' })).resolves.toBeUndefined()
+  })
+
+  it('turns the backend error envelope into an ApiError', async () => {
+    stubFetch({ error: { code: 'validation_failed', message: 'title: required' } }, 400)
+
+    const err = await apiFetch('/api/v1/items', { method: 'POST' }).catch(e => e)
+
+    expect(err).toBeInstanceOf(ApiError)
+    expect(err).toMatchObject({
+      status: 400,
+      code: 'validation_failed',
+      message: 'title: required',
+    })
+  })
+
+  it('falls back to statusText when the body is not the envelope', async () => {
+    stubFetch('<html>gateway timeout</html>', 504)
+
+    const err = await apiFetch('/api/v1/items').catch(e => e)
+
+    expect(err).toMatchObject({ status: 504, code: 'unknown', message: 'status text' })
+  })
+
+  it('wraps network failures (backend down) as a network ApiError', async () => {
+    vi.stubGlobal(
+      'fetch',
+      vi.fn().mockRejectedValue(new TypeError('fetch failed')),
+    )
+
+    const err = await apiFetch('/api/v1/items').catch(e => e)
+
+    expect(err).toBeInstanceOf(ApiError)
+    expect(err.code).toBe('network')
+    expect(err.message).toContain('Go server')
+  })
+})