fix: Make sure locker allows reentrant lock acquisition

test/unit/util/locking/PartialReadWriteLocker.test.ts

@@ -0,0 +1,25 @@
+import { PartialReadWriteLocker } from '../../../../src/util/locking/PartialReadWriteLocker';
+import type { ResourceLocker } from '../../../../src/util/locking/ResourceLocker';
+
+describe('A PartialReadWriteLocker', (): void => {
+  let resourceLocker: jest.Mocked<ResourceLocker>;
+  const resourceId = { path: 'http://test.com/resource' };
+  let locker: PartialReadWriteLocker;
+
+  beforeEach(async(): Promise<void> => {
+    resourceLocker = {
+      acquire: jest.fn(),
+      release: jest.fn(),
+    };
+
+    locker = new PartialReadWriteLocker(resourceLocker);
+  });
+
+  it('can lock resources.', async(): Promise<void> => {
+    await expect(locker.withReadLock(resourceId, (): number => 5)).resolves.toBe(5);
+    expect(resourceLocker.acquire).toHaveBeenCalledTimes(1);
+    expect(resourceLocker.acquire).toHaveBeenLastCalledWith(resourceId);
+    expect(resourceLocker.release).toHaveBeenCalledTimes(1);
+    expect(resourceLocker.release).toHaveBeenLastCalledWith(resourceId);
+  });
+});