Address TODO(AS4) in express4 directory (#6952)

Also make test subdirectory match source subdirectory.

Author: glasser

.changeset/light-kings-glow.md

@@ -0,0 +1,2 @@
+---
+---

packages/server/src/__tests__/express/expressSpecific.test.ts renamed to packages/server/src/__tests__/express4/expressSpecific.test.ts

@@ -1,7 +1,7 @@
 import express from 'express';
 import request from 'supertest';
 import compression, { filter as defaultFilter } from 'compression';
-import { ApolloServer } from '../../index.js';
+import { ApolloServer, BaseContext } from '../../index.js';
 import { expressMiddleware } from '../../express4/index.js';
 import { it, expect } from '@jest/globals';
 import resolvable from '@josephg/resolvable';
@@ -29,6 +29,27 @@ it('not calling start causes a clear error', async () => {
   );
 });
 
+it('context optional only if TContext=BaseContext', async () => {
+  const baseContextServer = new ApolloServer<BaseContext>({
+    typeDefs: 'type Query{x:ID}',
+  });
+  await baseContextServer.start();
+  const differentContextServer = new ApolloServer<{ x: number }>({
+    typeDefs: 'type Query{x:ID}',
+  });
+  await differentContextServer.start();
+
+  // This is a typechecking test, so we don't actually do anything with these
+  // middlewares.
+  expressMiddleware(baseContextServer);
+  expressMiddleware(baseContextServer, { context: async () => ({}) });
+  expressMiddleware(differentContextServer, {
+    context: async () => ({ x: 5 }),
+  });
+  // @ts-expect-error
+  expressMiddleware(differentContextServer);
+});
+
 // This test validates that you can use incremental delivery with the
 // `compression` package (which requires a hacky `res.flush()` call in the
 // middleware).

packages/server/src/__tests__/express/integration.test.ts renamed to packages/server/src/__tests__/express4/integration.test.ts

@@ -17,9 +17,6 @@ export interface ExpressMiddlewareOptions<TContext extends BaseContext> {
   context?: ContextFunction<[ExpressContextFunctionArgument], TContext>;
 }
 
-// TODO(AS4): Figure out exact naming (eg is this Express-specific or just Node
-// HTTP?)
-// TODO(AS4): Write compilation tests about the context optionality stuff.
 export function expressMiddleware(
   server: ApolloServer<BaseContext>,
   options?: ExpressMiddlewareOptions<BaseContext>,