Add simulation hooks for getMnemonicSeed

Author: FrederikBolding

packages/snaps-simulation/src/methods/hooks/get-mnemonic-seed.test.ts

@@ -0,0 +1,44 @@
+import { mnemonicPhraseToBytes } from '@metamask/key-tree';
+
+import { getGetMnemonicSeedImplementation } from './get-mnemonic-seed';
+import { DEFAULT_ALTERNATIVE_SRP, DEFAULT_SRP } from '../../constants';
+
+describe('getGetMnemonicSeedImplementation', () => {
+  it('returns the default mnemonic seed', async () => {
+    const getMnemonicSeed = getGetMnemonicSeedImplementation();
+    expect(await getMnemonicSeed()).toStrictEqual(
+      mnemonicPhraseToBytes(DEFAULT_SRP),
+    );
+
+    expect(await getMnemonicSeed('default')).toStrictEqual(
+      mnemonicPhraseToBytes(DEFAULT_SRP),
+    );
+  });
+
+  it('returns the seed of the provided default mnemonic phrase', async () => {
+    const getMnemonicSeed = getGetMnemonicSeedImplementation(
+      DEFAULT_ALTERNATIVE_SRP,
+    );
+    expect(await getMnemonicSeed()).toStrictEqual(
+      mnemonicPhraseToBytes(DEFAULT_ALTERNATIVE_SRP),
+    );
+
+    expect(await getMnemonicSeed('default')).toStrictEqual(
+      mnemonicPhraseToBytes(DEFAULT_ALTERNATIVE_SRP),
+    );
+  });
+
+  it('returns the alternative mnemonic seed', async () => {
+    const getMnemonicSeed = getGetMnemonicSeedImplementation();
+    expect(await getMnemonicSeed('alternative')).toStrictEqual(
+      mnemonicPhraseToBytes(DEFAULT_ALTERNATIVE_SRP),
+    );
+  });
+
+  it('throws an error for an unknown entropy source', async () => {
+    const getMnemonicSeed = getGetMnemonicSeedImplementation();
+    await expect(getMnemonicSeed('unknown')).rejects.toThrow(
+      'Entropy source with ID "unknown" not found.',
+    );
+  });
+});

packages/snaps-simulation/src/methods/hooks/get-mnemonic-seed.ts

@@ -0,0 +1,29 @@
+import { mnemonicToSeed } from '@metamask/key-tree';
+
+import { DEFAULT_ALTERNATIVE_SRP, DEFAULT_SRP } from '../../constants';
+
+/**
+ * Get the implementation of the `getMnemonicSeed` method.
+ *
+ * @param defaultSecretRecoveryPhrase - The default secret recovery phrase to
+ * use.
+ * @returns The implementation of the `getMnemonicSeed` method.
+ */
+export function getGetMnemonicSeedImplementation(
+  defaultSecretRecoveryPhrase: string = DEFAULT_SRP,
+) {
+  return async (source?: string | undefined): Promise<Uint8Array> => {
+    if (!source) {
+      return mnemonicToSeed(defaultSecretRecoveryPhrase);
+    }
+
+    switch (source) {
+      case 'default':
+        return mnemonicToSeed(defaultSecretRecoveryPhrase);
+      case 'alternative':
+        return mnemonicToSeed(DEFAULT_ALTERNATIVE_SRP);
+      default:
+        throw new Error(`Entropy source with ID "${source}" not found.`);
+    }
+  };
+}

packages/snaps-simulation/src/simulation.ts

@@ -44,6 +44,7 @@ import {
   getGetEntropySourcesImplementation,
   getGetMnemonicImplementation,
 } from './methods/hooks';
+import { getGetMnemonicSeedImplementation } from './methods/hooks/get-mnemonic-seed';
 import { createJsonRpcEngine } from './middleware';
 import type { SimulationOptions, SimulationUserOptions } from './options';
 import { getOptions } from './options';
@@ -108,6 +109,14 @@ export type RestrictedMiddlewareHooks = {
    */
   getMnemonic: (source?: string | undefined) => Promise<Uint8Array>;
 
+  /**
+   * A hook that returns the seed derived from the user's secret recovery phrase.
+   *
+   * @param source - The entropy source to get the seed from.
+   * @returns The seed.
+   */
+  getMnemonicSeed: (source?: string | undefined) => Promise<Uint8Array>;
+
   /**
    * A hook that returns whether the client is locked or not.
    *
@@ -382,6 +391,9 @@ export function getRestrictedHooks(
 ): RestrictedMiddlewareHooks {
   return {
     getMnemonic: getGetMnemonicImplementation(options.secretRecoveryPhrase),
+    getMnemonicSeed: getGetMnemonicSeedImplementation(
+      options.secretRecoveryPhrase,
+    ),
     getIsLocked: () => false,
     getClientCryptography: () => ({}),
   };

packages/snaps-simulator/src/features/simulation/sagas.ts

@@ -2,7 +2,7 @@ import { Messenger } from '@metamask/base-controller';
 import { createFetchMiddleware } from '@metamask/eth-json-rpc-middleware';
 import { JsonRpcEngine } from '@metamask/json-rpc-engine';
 import { createEngineStream } from '@metamask/json-rpc-middleware-stream';
-import { mnemonicPhraseToBytes } from '@metamask/key-tree';
+import { mnemonicPhraseToBytes, mnemonicToSeed } from '@metamask/key-tree';
 import type { GenericPermissionController } from '@metamask/permission-controller';
 import {
   PermissionController,
@@ -122,6 +122,7 @@ export function* initSaga({ payload }: PayloadAction<string>) {
 
   const sharedHooks = {
     getMnemonic: async () => mnemonicPhraseToBytes(srp),
+    getMnemonicSeed: async () => mnemonicToSeed(srp),
   };
 
   const permissionSpecifications = {