chore: add unit tests

Author: pregnantboy

packages/backend/src/helpers/__tests__/graphl-instance.test.ts

@@ -0,0 +1,26 @@
+import { assert, describe, expect, it } from 'vitest'
+
+import { server } from '../graphql-instance'
+
+describe('GraphQL instance', () => {
+  describe('Batching within an operation', () => {
+    it('should not throw an error if a single root fields is present', async () => {
+      const result = await server.executeOperation({
+        query: `query HealthCheck { healthcheck { version } }`,
+      })
+      assert(result.body.kind === 'single')
+      expect(result.body.singleResult.errors).toBeUndefined()
+    })
+
+    it('should throw an error if multiple root fields are present', async () => {
+      const result = await server.executeOperation({
+        query: `query TwoHealthChecks { h1: healthcheck { version } h2: healthcheck { version } }`,
+      })
+      assert(result.body.kind === 'single')
+      expect(result.body.singleResult.errors[0]).toHaveProperty(
+        'code',
+        'BAD_USER_INPUT',
+      )
+    })
+  })
+})

packages/backend/src/helpers/graphql-instance.ts

@@ -8,6 +8,7 @@ import { Kind, OperationDefinitionNode } from 'graphql/language'
 import { applyMiddleware } from 'graphql-middleware'
 
 import appConfig from '@/config/app'
+import { BadUserInputError } from '@/errors/graphql-errors'
 import { typeDefs } from '@/graphql/__generated__/typeDefs.generated'
 import resolvers from '@/graphql/resolvers'
 import authentication, { setCurrentUserContext } from '@/helpers/authentication'
@@ -43,7 +44,7 @@ function ApolloServerPluginUserTracer(): ApolloServerPlugin<AuthenticatedContext
   }
 }
 
-function preventBatching(): ApolloServerPlugin {
+function PreventBatching(): ApolloServerPlugin {
   return {
     async requestDidStart() {
       return {
@@ -54,13 +55,11 @@ function preventBatching(): ApolloServerPlugin {
             (definition) => definition.kind === Kind.OPERATION_DEFINITION,
           ) as OperationDefinitionNode | undefined
 
-          if (queryDefinition) {
-            // Check if there are multiple selections (root fields) in the query
-            if (queryDefinition.selectionSet.selections.length > 1) {
-              throw new Error(
-                'Multiple root fields in a single operation are not allowed.',
-              )
-            }
+          // Check if there are multiple selections (root fields) in the query
+          if (queryDefinition?.selectionSet.selections.length > 1) {
+            throw new BadUserInputError(
+              'Multiple root fields in a single operation are not allowed.',
+            )
           }
         },
       }
@@ -75,16 +74,18 @@ const schemaWithMiddleware = applyMiddleware(
   authentication.generate(schema),
 )
 
-const server = new ApolloServer<UnauthenticatedContext>({
+export const server = new ApolloServer<UnauthenticatedContext>({
   schema: schemaWithMiddleware,
   introspection: appConfig.isDev,
   plugins: [
     appConfig.isDev
       ? ApolloServerPluginLandingPageLocalDefault()
       : ApolloServerPluginLandingPageDisabled(),
     ApolloServerPluginUserTracer(),
-    preventBatching(),
+    PreventBatching(),
   ],
+  // We don't want to allow batching within a single HTTP request, this defaults to false
+  allowBatchedHttpRequests: false,
   formatError: (error) => {
     logger.error(error)
     let errorMessage = error.message