chore: improve V2 callable typing

[CorieW]

Resolves #260
Resolves #257

[Copilot]

Pull Request Overview

This PR loosens the typing of V2 callable functions by allowing callers to pass a deep partial of the CallableRequest, which can help in test scenarios or incremental data construction.

• Changed the WrappedV2CallableFunction parameter from a full CallableRequest to a DeepPartial<CallableRequest>.
• Adjusts type safety to be more flexible for users constructing request objects.

Comments suppressed due to low confidence (1)

src/v2.ts:38

• The change to accept partial requests should be covered by new or updated unit tests to ensure that missing properties are handled as expected by wrapped functions.

data: DeepPartial<CallableRequest>

[Copilot]

Using DeepPartial<CallableRequest> may allow invalid or incomplete payloads at runtime. Consider documenting which fields remain required or introduce a narrower helper type for testing vs. production usage.

[cabljac]

I'm not sure about this either, see for example:

import { wrapV2 } from 'firebase-functions-test/lib/v2';
import { onCall } from 'firebase-functions/v2/https';

interface HelloResult { greeting: string; }

const stub = onCall<{}, HelloResult>((req) => {

  console.log('HTTP method:', req.rawRequest.method);

  return { greeting: `Hello!` };
});

// 2) Wrap it
const invoke = wrapV2(stub);

// 3) This should be a compile‐time error, but compiles fine under the PR:
invoke({
  data: {},   // TS should complain: “Property 'rawRequest' is missing” etc
});

The change makes this fine according to the typescript compilation, but at runtime of the test we'll get an error.

I feel like the library should build some defaults?

like here in v1 for event context:

https://github.com/firebase/firebase-functions-test/blob/master/src/v1.ts#L141

[taeold]

This is a great call. Instead of loosening the type, maybe we just need to provide sensible default so that user doesn't have to manually construct and pass callable context when invoking their v2 callable fn.

[cabljac]

I'm not sure about this either, see for example:

import { wrapV2 } from 'firebase-functions-test/lib/v2';
import { onCall } from 'firebase-functions/v2/https';

interface HelloResult { greeting: string; }

const stub = onCall<{}, HelloResult>((req) => {

  console.log('HTTP method:', req.rawRequest.method);

  return { greeting: `Hello!` };
});

// 2) Wrap it
const invoke = wrapV2(stub);

// 3) This should be a compile‐time error, but compiles fine under the PR:
invoke({
  data: {},   // TS should complain: “Property 'rawRequest' is missing” etc
});

The change makes this fine according to the typescript compilation, but at runtime of the test we'll get an error.

I feel like the library should build some defaults?

like here in v1 for event context:

https://github.com/firebase/firebase-functions-test/blob/master/src/v1.ts#L141