refactor: extract helpers into kmeContentSourceAdapterHelpers.js

Move getValidToken, validateSettings, extractHydraItems, and buildSitemapXml
out of the proxy IIFE into src/globalVariables/kmeContentSourceAdapterHelpers.js
following the literal function body pattern (auto-loaded by server.js, injected
as 'kmeContentSourceAdapterHelpers' into VM context).

oidcAuthFlow() and sitemapFlow() remain in the proxy script as they own req/res.

Update unit and contract tests to evaluate the helpers file with the same mock
dependencies used in each VM context, ensuring error-throwing axios overrides
are correctly seen by the helpers' closures.

All 31 tests pass.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

tests/unit/proxy.test.js

@@ -13,6 +13,19 @@ const proxyPath = join(__dirname, '../../src/proxyScripts/kmeContentSourceAdapte
 const proxyCode = readFileSync(proxyPath, 'utf-8');
 const proxyScript = new vm.Script(proxyCode, { filename: 'kmeContentSourceAdapter.js' });
 
+const helpersPath = join(__dirname, '../../src/globalVariables/kmeContentSourceAdapterHelpers.js');
+const helpersCode = readFileSync(helpersPath, 'utf-8');
+const helpersWrapped = `(function() {\n${helpersCode}\n})()`;
+const helpersScript = new vm.Script(helpersWrapped, { filename: 'kmeContentSourceAdapterHelpers.js' });
+
+/**
+ * Evaluate the helpers file in a context built from the provided deps, returning
+ * the helpers object. Mirrors how server.js loads globalVariables/ JS files.
+ */
+function makeHelpers(deps) {
+  return helpersScript.runInContext(vm.createContext(deps));
+}
+
 /**
  * Build a minimal VM context satisfying the vm-context contract.
  * @param {import('node:test').TestContext} t
@@ -43,7 +56,7 @@ function makeContext(t, overrides = {}) {
     get headers() { return headers; },
   };
 
-  const kme_CSA_settings = {
+  const defaultSettings = {
     tokenUrl: 'https://auth.example.com/token',
     username: 'testuser',
     password: 'testpass',
@@ -51,22 +64,39 @@ function makeContext(t, overrides = {}) {
     scope: 'openid',
   };
 
-  const axiosMock = {
+  const defaultAxiosMock = {
     post: t.mock.fn(async () => ({
       data: { id_token: 'mock-token', expires_in: 9_999_999_999 },
     })),
     get: t.mock.fn(async () => ({
-      data: { items: [] },
+      data: { 'hydra:member': [] },
     })),
   };
 
+  // Resolve the final axios and settings — overrides take precedence.
+  // Helpers must close over the SAME axios/settings that the VM context will use,
+  // otherwise tests that pass error-throwing axios overrides would get helpers
+  // that still use the success-returning default.
+  const resolvedAxios = overrides.axios ?? defaultAxiosMock;
+  const resolvedSettings = overrides.kme_CSA_settings ?? defaultSettings;
+
+  const kmeContentSourceAdapterHelpers = makeHelpers({
+    URLSearchParams,
+    console,
+    axios: resolvedAxios,
+    redis,
+    kme_CSA_settings: resolvedSettings,
+    xmlBuilder,
+  });
+
   const ctx = vm.createContext({
     URLSearchParams,
     console,
-    axios: axiosMock,
+    axios: resolvedAxios,
     redis,
-    kme_CSA_settings,
+    kme_CSA_settings: defaultSettings,
     xmlBuilder,
+    kmeContentSourceAdapterHelpers,
     req: { url: '/', method: 'GET', headers: {} },
     res,
     ...overrides,
@@ -76,7 +106,7 @@ function makeContext(t, overrides = {}) {
   ctx._redis = redis;
   ctx._res = res;
   ctx._store = _store;
-  ctx._axios = axiosMock;
+  ctx._axios = resolvedAxios;
 
   return ctx;
 }
@@ -291,15 +321,23 @@ describe('stampede guard', () => {
     const res1 = makeRes(t);
     const res2 = makeRes(t);
 
+    // Helpers must share the same redis/kme_CSA_settings/axios so the stampede guard works
+    const sharedHelpers = makeHelpers({
+      URLSearchParams, console, axios: sharedAxios,
+      redis, kme_CSA_settings, xmlBuilder,
+    });
+
     const ctx1 = vm.createContext({
       URLSearchParams, console, axios: sharedAxios,
       redis, kme_CSA_settings, xmlBuilder,
+      kmeContentSourceAdapterHelpers: sharedHelpers,
       req: { url: '/', method: 'GET', headers: {} },
       res: res1,
     });
     const ctx2 = vm.createContext({
       URLSearchParams, console, axios: sharedAxios,
       redis, kme_CSA_settings, xmlBuilder,
+      kmeContentSourceAdapterHelpers: sharedHelpers,
       req: { url: '/', method: 'GET', headers: {} },
       res: res2,
     });