chore: establish learning module baseline

OpenMAIC/packages/@openmaic/storage/test/setup.ts

@@ -0,0 +1,81 @@
+// Test shims for the handful of browser globals the backends touch that Node
+// does not provide natively. The backends themselves take their `Storage` /
+// `IDBFactory` by injection, so tests pass fresh isolated instances; these
+// shims only cover the ambient APIs (object URLs, IndexedDB key ranges,
+// crypto) a real browser supplies.
+import { webcrypto } from 'node:crypto';
+import { IDBKeyRange } from 'fake-indexeddb';
+import { beforeEach } from 'vitest';
+
+// Node ≥20 exposes `globalThis.crypto`, but guard for older/edge runners so
+// content-hashing (crypto.subtle.digest) works the same as in a browser.
+if (!globalThis.crypto?.subtle) {
+  Object.defineProperty(globalThis, 'crypto', { value: webcrypto, configurable: true });
+}
+
+// The runtime backend builds its ranged record reads with the ambient
+// `IDBKeyRange`, which real browsers always pair with `indexedDB` but Node
+// lacks — supply the fake-indexeddb one that matches the injected factories.
+if (!('IDBKeyRange' in globalThis)) {
+  globalThis.IDBKeyRange = IDBKeyRange;
+}
+
+// object-URL registry: `createObjectURL(blob)` mints a unique `blob:` URL and
+// remembers the blob so tests can resolve the URL back to its bytes (the real
+// browser provides both natively; Node provides neither).
+const objectUrls = new Map<string, Blob>();
+let seq = 0;
+
+URL.createObjectURL = (obj: Blob | MediaSource): string => {
+  const url = `blob:maic-test/${seq++}`;
+  objectUrls.set(url, obj as Blob);
+  return url;
+};
+URL.revokeObjectURL = (url: string): void => {
+  objectUrls.delete(url);
+};
+
+/** Test-only: resolve an object URL minted by the polyfill back to its blob. */
+export function blobForObjectUrl(url: string): Blob | undefined {
+  return objectUrls.get(url);
+}
+
+/** Test-only: number of currently live object URLs in the polyfill registry. */
+export function objectUrlCount(): number {
+  return objectUrls.size;
+}
+
+// Reset the object-URL registry between tests so nothing bleeds across cases
+// (the override is a global; without this the map grows for the whole run).
+beforeEach(() => {
+  objectUrls.clear();
+  seq = 0;
+});
+
+/**
+ * Test-only in-memory `Storage` (localStorage-shaped) for injecting into the
+ * browser KV backend. A fresh instance per test keeps cases isolated without
+ * touching any ambient global.
+ */
+export class MemoryStorage implements Storage {
+  private readonly m = new Map<string, string>();
+  get length(): number {
+    return this.m.size;
+  }
+  clear(): void {
+    this.m.clear();
+  }
+  getItem(key: string): string | null {
+    return this.m.has(key) ? this.m.get(key)! : null;
+  }
+  key(index: number): string | null {
+    return [...this.m.keys()][index] ?? null;
+  }
+  removeItem(key: string): void {
+    this.m.delete(key);
+  }
+  setItem(key: string, value: string): void {
+    this.m.set(key, String(value));
+  }
+  [name: string]: unknown;
+}