test: add test to assert js resolver is valid js

Author: Dane Pilcher

packages/backend-data/src/convert_js_resolvers.test.ts

@@ -6,10 +6,15 @@ import {
   AmplifyData,
   AmplifyDataDefinition,
 } from '@aws-amplify/data-construct';
-import { resolve } from 'path';
+import { join, resolve } from 'path';
+import { tmpdir } from 'os';
 import { fileURLToPath } from 'url';
-import { convertJsResolverDefinition } from './convert_js_resolvers.js';
+import {
+  convertJsResolverDefinition,
+  defaultJsResolverCode,
+} from './convert_js_resolvers.js';
 import { a } from '@aws-amplify/data-schema';
+import { writeFileSync } from 'node:fs';
 
 // stub schema for the AmplifyApi construct
 // not relevant to this test suite
@@ -28,6 +33,29 @@ const createStackAndSetContext = (): Stack => {
   return stack;
 };
 
+void describe('defaultJsResolverCode', () => {
+  void it('returns the default JS resolver code with api id and env name in valid JS', async () => {
+    const code = defaultJsResolverCode('testApiId', 'testEnvName');
+    assert(code.includes("ctx.stash.awsAppsyncApiId = 'testApiId';"));
+    assert(code.includes("ctx.stash.amplifyBranchName = 'testEnvName';"));
+
+    const tempDir = tmpdir();
+    const filename = join(tempDir, 'js_resolver_handler.js');
+    writeFileSync(filename, code);
+
+    const resolver = await import(filename);
+    const context = { stash: {}, prev: { result: 'result' } };
+    assert.deepEqual(resolver.request(context), {});
+
+    // assert api id and env name are added to the context stash
+    assert.deepEqual(context.stash, {
+      awsAppsyncApiId: 'testApiId',
+      amplifyBranchName: 'testEnvName',
+    });
+    assert.equal(resolver.response(context), 'result');
+  });
+});
+
 void describe('convertJsResolverDefinition', () => {
   let stack: Stack;
   let amplifyApi: AmplifyData;

packages/backend-data/src/convert_js_resolvers.ts

@@ -22,7 +22,7 @@ const JS_PIPELINE_RESOLVER_HANDLER = './assets/js_resolver_handler.js';
  *
  * Add Amplify API ID and environment name to the context stash for use in the customer-provided handlers.
  */
-const defaultJsResolverCode = (
+export const defaultJsResolverCode = (
   amplifyApiId: string,
   amplifyEnvironmentName: string
 ): string => {