feat: add mock call history to access request configuration in test

[blephy]

This relates to...

#4025

Rationale

Actually we are not able with MockAgent to assert request configuration.

Given this in mind, the only way we could do it is by wrapping our app http call in function, and then spy or mock that function with our favorite test framework. We can make assertions on parameters we passed through that function but, even with this possibility, we are not certain that undici did not make computation on inputs.

This PR is addressing this problematic : ensuring http calls are made with the expected low level configuration, as far as we can.

Changes

• add MockCallHistory and MockCallHistoryLog class
• add registerCallHistory class method to MockScope instance
• add clearAllCallHistory class method to MockAgent instance
• add disableCallHistory class method to MockAgent instance
• add enableCallHistory class method to MockAgent instance
• add enableCallHistory MockAgent instantiation options
• delete all call history instances when MockAgent.close is called

Features

Given this application :

function myCall(body: Record<string, unknown>, token: string) {
  await fetch(`https://my-service.io/endpoint`, {
      method: 'POST',
      body: JSON.stringify(body),
      headers: {
        authorization: 'Bearer ${token}',
        'content-type': 'application/json'
      }
  })
}

async function startApp(): Promise<void> {
  await myCall({ data: 'hello' }, 'myToken')
}

After :

describe('my app', () => {
  let agent: MockAgent

  before(() => {
    agent = new MockAgent({ enableCallHistory: true })
    setGlobalDispatcher(agent)
  })

  beforeEach(() => {
    agent.clearAllCallHistory()
  })

  after(async () => {
    await agent.close()
  })

  it('should request my external service with a specific body and headers', async () => {
    mockAgent.get('https://my-service.io').intercept({ path: '/endpoint', method: 'POST' }).reply(201, 'OK').times(1)

    await startApp()

    expect(mockAgent.getCallHistory()?.firstCall()?.body).toStrictEqual('"{ "data": "hello" }"')
    expect(mockAgent.getCallHistory()?.firstCall()?.headers['authorization']).toStrictEqual('Bearer myToken')
    expect(mockAgent.getCallHistory()?.firstCall()?.headers['content-type']).toStrictEqual('application/json')
    expect(mockAgent.getCallHistory()?.firstCall()?.path).toStrictEqual('/endpoint')
    expect(mockAgent.getCallHistory()?.firstCall()?.protocol).toStrictEqual('https:')
    expect(mockAgent.getCallHistory()?.calls()?.length).toStrictEqual(1)
  })

  it('should always call external services with a secure HTTP protocol', async () => {
    await startApp()

    // working without intercepting too

    expect(mockAgent.getCallHistory()?.filterCalls({ protocol: /^((?!https).)*$/ })?.length).toStrictEqual(0)
  })
})

Before :

describe('my app', () => {
  let agent: MockAgent

  before(() => {
    agent = new MockAgent({ enableCallHistory: true })
    setGlobalDispatcher(agent)
  })

  beforeEach(() => {
    agent.clearAllCallHistory()
  })

  after(async () => {
    await agent.close()
  })

  it('should request my external service with a specific body and headers', async () => {
    const spy = spyOn(myCall)
    mockAgent.get('https://my-service.io').intercept({ path: '/endpoint', method: 'POST' }).reply(201, 'OK').times(1)

    await startApp()

    expect(spy.calls?.[0]).toHaveBeenCalledWith({ data: 'hello' }, 'myToken')
    // we cannot do it, we must modify our application code and this will only assert function parameters, not the real http request
    // expect(mockAgent.getCallHistory()?.firstCall()?.headers['authorization']).toMatch(/^Bearer /)
    // we cannot do it, we must modify our application code and this will only assert function parameters, not the real http request
    // expect(mockAgent.getCallHistory()?.firstCall()?.headers['content-type']).toStrictEqual('application/json')
    // we cannot do it, we must modify our application code and this will only assert function parameters, not the real http request
    // expect(mockAgent.getCallHistory()?.firstCall()?.path).toStrictEqual('/endpoint')
    // we cannot do it, we must modify our application code and this will only assert function parameters, not the real http request
    // expect(mockAgent.getCallHistory()?.firstCall()?.protocol).toStrictEqual('https:')
    expect(spy.calls.length).toStrictEqual(1)
  })

  it('should always call external services with a secure HTTP protocol', async () => {
    await startApp()

    // we cannot do it, we must modify our application code and this will only assert function parameters, not the real http request
    // expect(mockAgent.getCallHistory()?.filterCalls({ protocol: /^((?!https).)*$/ })?.length).toStrictEqual(0)
  })
})

Bug Fixes

Breaking Changes and Deprecations

Status

• I have read and agreed to the Developer's Certificate of Origin
• Tested
• Benchmarked (optional)
• Documented
• Review ready
• In review
• Merge ready

[metcoder95]

Can you add testing for it?

[blephy]

Yes for sur. I just need times

[mcollina]

Thanks for opening a PR! Can you please add a unit test?

[metcoder95]

lgtm, small comment left

[metcoder95]

LGTM, left minor comment and should be ready on my end

[blephy]

@mcollina can you take a bit of time to review back this PR ? it would be nice to have this change in the next release 🙏🏼