Stateful Behavior - Is it possible to return different responses to the same request depending on a state/scenario?

[commencisreview]

There would be some requests that the headers, body and url paths are the same, but the expected responses are different depending on their states in a scenario flow. Wiremock has a solution named as Scenario. Is it possible to solve this branching in Camouflage Mock?

For example, in a banking service;

• You have an GET accounts request. You want the first response with an empty accounts list.
• After requesting POST addAccount including accountId in json body, you expect to see a non-empty accounts list for GET accounts request.

[is-jonreeves]

I only just stumbled across this project a few hours ago and have been reading the docs/code. I had a similar thought...

At first I wondered if you might be able to utilize the State Helper in combination with the Request Matching like how its shown in the External Helpers page. But I couldn't quite figure out how to make use of the value.

I was assuming that we might set a single Cookie that would look like this:

mocked-state-test-scenario: '{ "id": "TC-0001", "stage": "a", "scenario": "Initial Visit" }'

But skimming the code, I don't see a way to use capture with state and it would need using='jsonpath' anyways to make this approach work.

I suppose we could do it with separate cookies instead, and then it looks pretty easy to run them through capture and assign.

We can make use of a Set-Cookie in the mock responses to change/drive the state, without having to manage the state step-by-step from within any tests. Might look something like...

Mock File Examples

<!-- /mocks/api/accounts/GET.mock -->
{{assign name='testId' value=(capture from='headers' key='x-test-id')}}
{{assign name='testState' value=(capture from='headers' key='x-test-state')}}
{{assign name='testScenarioFile' value=(concat "./GET.scenario." testId "." testState ".mock")}}

{{#is testId 'TC-0001' }}
  {{#is testState 'INITIAL' }}{{file path=testScenarioFile}}{{/is}}
  {{#is testState 'ACCOUNT_CREATE_SUCCESS' }}{{file path=testScenarioFile}}{{/is}}
{{/is}}

{{#is testId 'TC-0002' }}
  {{#is testState 'INITIAL' }}{{file path=testScenarioFile}}{{/is}}
  {{#is testState 'ACCOUNT_CREATE_FAILURE' }}{{file path=testScenarioFile}}{{/is}}
{{/is}}

{{#unless testId }}{{file path='./GET.scenario.DEFAULT.mock'}}{{/unless}}

<!-- /mocks/api/accounts/GET.scenario.DEFAULT.mock -->
HTTP/1.1 200 OK
Content-Type: application/json

[
  { "id": 1, "name": "Account 1" },
  { "id": 2, "name": "Account 2" }
]

<!-- /mocks/api/accounts/GET.scenario.TC-0001.INITIAL.mock -->
HTTP/1.1 200 OK
Content-Type: application/json

[
  { "id": 1, "name": "Account 1" },
  { "id": 2, "name": "Account 2" }
]

<!-- /mocks/api/accounts/GET.scenario.TC-0001.ACCOUNT_CREATE_SUCCESS.mock -->
HTTP/1.1 200 OK
Content-Type: application/json

[
  { "id": 1, "name": "Account 1" },
  { "id": 2, "name": "Account 2" },
  { "id": 3, "name": "Account 3" }
]

<!-- /mocks/api/accounts/GET.scenario.TC-0002.INITIAL.mock -->
HTTP/1.1 200 OK
Content-Type: application/json

[
  { "id": 1, "name": "Account 1" },
  { "id": 2, "name": "Account 2" }
]

<!-- /mocks/api/accounts/GET.scenario.TC-0002.ACCOUNT_CREATE_FAILURE.mock -->
HTTP/1.1 200 OK
Content-Type: application/json

[
  { "id": 1, "name": "Account 1" },
  { "id": 2, "name": "Account 2" }
]

<!-- /mocks/api/accounts/POST.mock -->
{{assign name='testId' value=(capture from='headers' key='x-test-id')}}
{{assign name='testState' value=(capture from='headers' key='x-test-state')}}
{{assign name='testScenarioFile' value=(concat "./POST.scenario." testId "." testState ".mock")}}

{{#is testId 'TC-0001' }}
  {{#is testState 'INITIAL' }}{{file path=testScenarioFile}}{{/is}}
{{/is}}

{{#is testId 'TC-0002' }}
  {{#is testState 'INITIAL' }}{{file path=testScenarioFile}}{{/is}}
{{/is}}

<!-- /mocks/api/accounts/POST.scenario.TC-0001.INITIAL.mock -->
HTTP/1.1 200 OK
Content-Type: application/json
Set-Cookie: x-test-state=ACCOUNT_CREATE_SUCCESS

{ "id": 3, "name": "Account 3" }

<!-- /mocks/api/accounts/POST.scenario.TC-0002.INITIAL.mock -->
HTTP/1.1 400 Bad Request
Content-Type: application/json
Set-Cookie: x-test-state=ACCOUNT_CREATE_FAILURE

{ "code": 4, "message": "Invalid account 'name'" }

Playwright Example

// Utils (probably better as a fixture)
const setTestInfo = async (context: BrowserContext, records: Record<string, any>, prefix = 'x-test') => {
  await context.addCookies(Object.entries(records).reduce((acc, [key, val]) => {
    acc.push({ name: [prefix, key].join('-'), value: `${val}` });
    return acc;
  }, [] as [{ name: string, value: string }]));
};

// Usage
const browser = await chromium.launch();
const context = await browser.newContext();
const page = await browser.newPage();

/** [TC-0001/INITIAL] - Initial page load */
await setTestInfo(context, { id, state: 'INITIAL' });
await page.goto(...);
  // 1. Started as: `x-test-state: INITIAL`
  // 2. [GET] completed...
await expect(...).toBe(...);

/** [TC-0001/ACCOUNT_CREATE_SUCCESS] - After a new account was successfully created */
await setTestInfo(context, { id, state: 'INITIAL' });
await page.goto(...);
  // 1. Started as: `x-test-state: INITIAL`
  // 2. [GET] completed...
await expect(...).toBe(...);
await page.getByRole('button', { name: 'Create Account' }).click();
  // 3. Still as: `x-test-state: INITIAL`
  // 4. [POST] completed...
  // 5. Changed to: `x-test-state: ACCOUNT_CREATE_SUCCESS`
  // 6. Subsequent [GET] uses new 'state'...
await expect(...).toBe(...);

...

---

Again, I've not used camouflage yet, but "if" the above works it would seem like an elegant enough approach.