feat: Introduce internal storing mechanism

test/unit/storage/keyvalue/ResourceIdentifierStorage.test.ts

@@ -0,0 +1,37 @@
+import type { KeyValueStorage } from '../../../../src/storage/keyvalue/KeyValueStorage';
+import { ResourceIdentifierStorage } from '../../../../src/storage/keyvalue/ResourceIdentifierStorage';
+
+describe('A ResourceIdentifierStorage', (): void => {
+  const path = 'http://test.com/foo';
+  const identifier = { path };
+  let source: KeyValueStorage<string, number>;
+  let storage: ResourceIdentifierStorage<number>;
+
+  beforeEach(async(): Promise<void> => {
+    source = {
+      get: jest.fn(),
+      has: jest.fn(),
+      set: jest.fn(),
+      delete: jest.fn(),
+    };
+    storage = new ResourceIdentifierStorage(source);
+  });
+
+  it('calls the corresponding function on the source Storage.', async(): Promise<void> => {
+    await storage.get(identifier);
+    expect(source.get).toHaveBeenCalledTimes(1);
+    expect(source.get).toHaveBeenLastCalledWith(path);
+
+    await storage.has(identifier);
+    expect(source.has).toHaveBeenCalledTimes(1);
+    expect(source.has).toHaveBeenLastCalledWith(path);
+
+    await storage.set(identifier, 5);
+    expect(source.set).toHaveBeenCalledTimes(1);
+    expect(source.set).toHaveBeenLastCalledWith(path, 5);
+
+    await storage.delete(identifier);
+    expect(source.delete).toHaveBeenCalledTimes(1);
+    expect(source.delete).toHaveBeenLastCalledWith(path);
+  });
+});