update @requires test to verify the functionality

Updating `users` and `products` subgraph schemas to allow for testing the support of `@requires` functionality in the implementing subgraph. This is a breaking change as we modify the schema so all the existing implementations will be impacted.

Changes:
* `users` subgraph
```graphql
type User @key(fields:"email") {
  email:ID!
  name: String
  totalProductsCreated: Int
  yearsOfEmployment: Int! # <-- new field
}
```
* `products` subgraph
```graphql
extend type User @key(fields: "email") {
  averageProductsCreatedPerYear: Int @requires(fields: "yearsOfEmployment") # <-- test `@requires` functionality
  email: ID! @external
  name: String @OverRide(from: "users")
  totalProductsCreated: Int @external
  yearsOfEmployment: Int! @external # <-- field from the users subgraph used by @requires
}
```

Updated implementations:

- [x] apollo-server
- [x] federation-jvm
- [x] graphql-kotlin

Related Issues:

* resolves #128

README.md

@@ -174,6 +174,7 @@ type User @key(fields: "email") {
   email: ID!
   name: String
   totalProductsCreated: Int
+  yearsOfEmployment: Int!
 }
 ```
 
@@ -244,9 +245,11 @@ extend type Query {
 }
 
 extend type User @key(fields: "email") {
+  averageProductsCreatedPerYear: Int @requires(fields: "yearsOfEmployment")
   email: ID! @external
   name: String @override(from: "users")
   totalProductsCreated: Int @external
+  yearsOfEmployment: Int! @external
 }
 ```
 
@@ -279,14 +282,14 @@ query ($representations: [_Any!]!) {
 
 - `@key` and `_entities` - multiple `@key` definitions, multiple-fields `@key` and a complex fields `@key`. 
 - `@requires` - directive used to provide additional non-key information from one subgraph to the computed fields in another subgraph, should support defining complex fields
-  - This will be tested through a query covering [Product.delivery](http://product.delivery) where the library implementors `dimensions { size weight }` will need to be an expected `{ size: "1", weight: 1 }` to pass. Example query that will be sent directly to `products` subgraph.
+- - This will be covered by the subgraph implementors at `Product.createdBy` where they will be expected to provide the `User.averageProductsCreatedPerYear` using `yearsOfEmployment` value provided by the `user` graph and the `totalProductsCreated` value from the implementing `products` subgraph. Example query that will be sent directly to `products` subgraph.
 
 ```graphql
 query ($id: ID!) {
   product(id: $id) {
-    dimensions {
-      size
-      weight
+    createdBy {
+      averageProductsCreatedPerYear
+      email
     }
   }
 }

implementations/_template_hosted_/products.graphql

@@ -1,6 +1,6 @@
 extend schema
   @link(url: "https://specs.apollo.dev/federation/v2.0",
-        import: ["@key", "@shareable", "@provides", "@external", "@tag", "@extends", "@override", "@inaccessible"])
+        import: ["@key", "@shareable", "@provides", "@external", "@tag", "@extends", "@override", "@inaccessible", "@requires"])
 
 directive @override(from: String!) on FIELD_DEFINITION
 
@@ -29,7 +29,9 @@ extend type Query {
 }
 
 extend type User @key(fields: "email") {
+  averageProductsCreatedPerYear: Int @requires(fields: "yearsOfEmployment")
   email: ID! @external
-  name: String @shareable @override(from: "users")
+  name: String @override(from: "users")
   totalProductsCreated: Int @external
+  yearsOfEmployment: Int! @external
 }

implementations/_template_library_/products.graphql

@@ -1,6 +1,6 @@
 extend schema
   @link(url: "https://specs.apollo.dev/federation/v2.0",
-        import: ["@key", "@shareable", "@provides", "@external", "@tag", "@extends", "@override", "@inaccessible"])
+        import: ["@key", "@shareable", "@provides", "@external", "@tag", "@extends", "@override", "@inaccessible", "@requires"])
 
 directive @override(from: String!) on FIELD_DEFINITION
 
@@ -29,7 +29,9 @@ extend type Query {
 }
 
 extend type User @key(fields: "email") {
+  averageProductsCreatedPerYear: Int @requires(fields: "yearsOfEmployment")
   email: ID! @external
-  name: String @shareable @override(from: "users")
+  name: String @override(from: "users")
   totalProductsCreated: Int @external
+  yearsOfEmployment: Int! @external
 }

implementations/apollo-server/index.js

@@ -68,3 +68,4 @@ const server = new ApolloServer({
 server
   .listen({ port })
   .then(({ url }) => console.log(`Products subgraph ready at ${url}`));
+

router.yaml

@@ -1,4 +1,4 @@
 server:
   listen: 0.0.0.0:4000
   cors:
-    allow_credentials: true
+    allow_credentials: true

src/tests/override.test.ts

@@ -1,4 +1,4 @@
-import { productsRequest, graphqlRequest, ROUTER_URL } from "../utils/client";
+import { productsRequest, routerRequest } from "../utils/client";
 import { compareSchemas } from "../utils/schemaComparison";
 import { stripIgnoredCharacters } from "graphql";
 
@@ -15,7 +15,7 @@ describe("@override", () => {
   });
 
   it("should return overridden user name", async () => {
-    const resp = await graphqlRequest(ROUTER_URL, {
+    const resp = await routerRequest({
       query: `
         query GetProduct($id: ID!) {
           product(id: $id) {

src/tests/requires.test.ts

@@ -1,20 +1,20 @@
-import { productsRequest } from "../utils/client";
+import { routerRequest } from "../utils/client";
 
 test("@requires", async () => {
-  const resp = await productsRequest({
+  const resp = await routerRequest({
     query: `#graphql
       query ($id: ID!) {
-        product(id: $id) { dimensions { size weight } }
+        product(id: $id) { createdBy { averageProductsCreatedPerYear email } }
       }`,
     variables: { id: "apollo-federation" },
   });
 
   expect(resp).toMatchObject({
     data: {
       product: {
-        dimensions: {
-          size: "small",
-          weight: 1,
+        createdBy: {
+          averageProductsCreatedPerYear: expect.any(Number),
+          email: "support@apollographql.com",
         },
       },
     },

src/tests/shareable.test.ts

@@ -1,4 +1,4 @@
-import { productsRequest, graphqlRequest, ROUTER_URL } from "../utils/client";
+import { productsRequest, routerRequest } from "../utils/client";
 import { compareSchemas } from "../utils/schemaComparison";
 import { stripIgnoredCharacters } from "graphql";
 
@@ -17,7 +17,7 @@ describe("@shareable", () => {
   });
 
   it("should be able to resolve @shareable ProductDimension types", async () => {
-    const resp = await graphqlRequest(ROUTER_URL, {
+    const resp = await routerRequest({
       query: `
         query GetProduct($id: ID!) {
           product(id: $id) {

src/utils/client.ts

@@ -32,6 +32,17 @@ export async function graphqlRequest(
   return resp.text();
 }
 
+export function routerRequest(
+  req: {
+    query: string;
+    variables?: { [key: string]: any };
+    operationName?: string;
+  },
+  headers?: { [key: string]: any }
+) {
+  return graphqlRequest(ROUTER_URL, req, headers);
+}
+
 export function productsRequest(
   req: {
     query: string;

subgraphs/users/index.js

@@ -8,6 +8,7 @@ const users = [
     email: "support@apollographql.com",
     name: "Apollo Studio Support",
     totalProductsCreated: 4,
+    yearsOfEmployment: 4
   },
 ];
 

subgraphs/users/users.graphql

@@ -2,4 +2,5 @@ type User @key(fields:"email") {
   email:ID!
   name: String
   totalProductsCreated: Int
+  yearsOfEmployment: Int!
 }

supergraph.graphql

@@ -94,7 +94,9 @@ type User
   @join__type(graph: PRODUCTS, key: "email", extension: true)
   @join__type(graph: USERS, key: "email")
 {
+  averageProductsCreatedPerYear: Int @join__field(graph: PRODUCTS, requires: "yearsOfEmployment")
   email: ID!
   name: String @join__field(graph: PRODUCTS, override: "users")
   totalProductsCreated: Int @join__field(graph: PRODUCTS, external: true) @join__field(graph: USERS)
+  yearsOfEmployment: Int! @join__field(graph: PRODUCTS, external: true) @join__field(graph: USERS)
 }