feat(kernel-test): Use mock logger where possible

Author: grypez

packages/kernel-test/src/garbage-collection.test.ts

@@ -2,7 +2,6 @@ import '@metamask/kernel-shims/endoify';
 import type { KernelDatabase } from '@metamask/kernel-store';
 import { makeSQLKernelDatabase } from '@metamask/kernel-store/sqlite/nodejs';
 import { waitUntilQuiescent } from '@metamask/kernel-utils';
-import { Logger } from '@metamask/logger';
 import { Kernel, kunser, makeKernelStore } from '@metamask/ocap-kernel';
 import type {
   ClusterConfig,
@@ -15,7 +14,7 @@ import { expect, beforeEach, describe, it } from 'vitest';
 import {
   getBundleSpec,
   makeKernel,
-  makeTestLogger,
+  makeMockLogger,
   parseReplyBody,
   runTestVats,
 } from './utils.ts';
@@ -54,15 +53,13 @@ describe('Garbage Collection', () => {
   let importerKRef: KRef;
   let exporterVatId: VatId;
   let importerVatId: VatId;
-  let logger: Logger;
 
   beforeEach(async () => {
-    logger = makeTestLogger().logger;
     kernelDatabase = await makeSQLKernelDatabase({
       dbFilename: ':memory:',
     });
     kernelStore = makeKernelStore(kernelDatabase);
-    kernel = await makeKernel(kernelDatabase, true, logger);
+    kernel = await makeKernel(kernelDatabase, true, makeMockLogger());
     await runTestVats(kernel, makeTestSubcluster());
 
     const vats = kernel.getVats();

packages/kernel-test/src/utils.ts

@@ -14,6 +14,7 @@ import {
   MessagePort as NodeMessagePort,
   MessageChannel as NodeMessageChannel,
 } from 'node:worker_threads';
+import { vi } from 'vitest';
 
 /**
  * Construct a bundle path URL from a bundle name.
@@ -182,3 +183,23 @@ export const makeTestLogger = (): { logger: Logger; entries: LogEntry[] } => {
   const logger = new Logger({ transports: [makeArrayTransport(entries)] });
   return { logger, entries };
 };
+
+/**
+ * Create a mock logger that can be used to spy on the logger methods.
+ * Derived sub-loggers will invoke the parent logger methods directly.
+ * The injectStream method is a no-op.
+ *
+ * @returns A mock logger.
+ */
+export const makeMockLogger = (): Logger => {
+  const mockLogger = {
+    log: vi.fn(),
+    error: vi.fn(),
+    warn: vi.fn(),
+    info: vi.fn(),
+    debug: vi.fn(),
+    subLogger: vi.fn(() => mockLogger),
+    injectStream: vi.fn(),
+  } as unknown as Logger;
+  return mockLogger;
+};