remoteConfigurationFetch.spec.ts

import { interceptRequests } from '@datadog/browser-core/test'
import { fetchRemoteConfiguration } from './remoteConfigurationFetch'

describe('fetchRemoteConfiguration', () => {
  const options = { site: 'datadoghq.com', remoteConfigurationId: 'test-id' }
  let interceptor: ReturnType<typeof interceptRequests>

  beforeEach(() => {
    interceptor = interceptRequests()
  })

  it('returns ok:true with the parsed config on success', async () => {
    const config = { rum: { applicationId: 'abc', sessionSampleRate: 50 } }
    interceptor.withFetch(() =>
      Promise.resolve({
        ok: true,
        json: () => Promise.resolve(config),
      })
    )

    const result = await fetchRemoteConfiguration(options)
    expect(result).toEqual({ ok: true, value: config })
  })

  it('returns ok:false on HTTP error (non-ok response)', async () => {
    interceptor.withFetch(() => Promise.resolve({ ok: false, status: 404 }))

    const result = await fetchRemoteConfiguration(options)
    expect(result.ok).toBeFalse()
    expect((result as { ok: false; error: Error }).error).toBeInstanceOf(Error)
  })

  it('returns ok:false on network failure (fetch throws)', async () => {
    interceptor.withFetch(() => Promise.reject(new Error('Network error')))

    const result = await fetchRemoteConfiguration(options)
    expect(result.ok).toBeFalse()
    expect((result as { ok: false; error: Error }).error).toBeInstanceOf(Error)
  })

  it('returns ok:false when response body is not valid JSON', async () => {
    interceptor.withFetch(() =>
      Promise.resolve({
        ok: true,
        json: () => Promise.reject(new SyntaxError('Unexpected end of JSON input')),
      })
    )

    const result = await fetchRemoteConfiguration(options)
    expect(result.ok).toBeFalse()
    expect((result as { ok: false; error: Error }).error).toBeInstanceOf(Error)
  })

  it('removes the window registry entry after all fetches settle', async () => {
    const config = { rum: { applicationId: 'abc', sessionSampleRate: 50 } }
    interceptor.withFetch(() => Promise.resolve({ ok: true, json: () => Promise.resolve(config) }))

    await fetchRemoteConfiguration(options)

    expect((window as unknown as Record<string, unknown>).__ddRcInflight).toBeUndefined()
  })

  it('deduplicates concurrent calls for the same endpoint', async () => {
    let fetchCount = 0
    const config = { rum: { applicationId: 'abc', sessionSampleRate: 50 } }
    interceptor.withFetch(() => {
      fetchCount++
      return Promise.resolve({ ok: true, json: () => Promise.resolve(config) })
    })

    const [result1, result2] = await Promise.all([fetchRemoteConfiguration(options), fetchRemoteConfiguration(options)])

    expect(fetchCount).toBe(1)
    expect(result1).toEqual({ ok: true, value: config })
    expect(result2).toEqual({ ok: true, value: config })
  })
})