Add assertions for crypto and SubtleCrypto

Author: Mrtenz

packages/snaps-execution-environments/src/common/endowments/crypto.ts

@@ -1,6 +1,18 @@
+import { assert } from '@metamask/utils';
+
 import { rootRealmGlobal } from '../globalObject';
 
 export const createCrypto = () => {
+  assert(
+    rootRealmGlobal.crypto,
+    'Crypto endowment requires `globalThis.crypto` to be defined.',
+  );
+
+  assert(
+    rootRealmGlobal.SubtleCrypto,
+    'Crypto endowment requires `globalThis.SubtleCrypto` to be defined.',
+  );
+
   return {
     crypto: harden(rootRealmGlobal.crypto),
     SubtleCrypto: harden(rootRealmGlobal.SubtleCrypto),