Add unit test

Author: EmilianoSanchez

src/storages/inLocalStorage/MySegmentsCacheInLocal.ts

@@ -51,7 +51,7 @@ export class MySegmentsCacheInLocal extends AbstractMySegmentsCacheSync {
 
   getRegisteredSegments(): string[] {
     const registeredSegments: string[] = [];
-    for (let i = 0; i < this.storage.length; i++) {
+    for (let i = 0, len = this.storage.length; i < len; i++) {
       const segmentName = this.keys.extractSegmentName(this.storage.key(i)!);
       if (segmentName) registeredSegments.push(segmentName);
     }

src/storages/inLocalStorage/__tests__/storageAdapter.spec.ts

@@ -0,0 +1,58 @@
+import { storageAdapter } from '../storageAdapter';
+import { loggerMock } from '../../../logger/__tests__/sdkLogger.mock';
+
+
+const syncWrapper = {
+  getItem: jest.fn(() => JSON.stringify({ key1: 'value1' })),
+  setItem: jest.fn(),
+  removeItem: jest.fn(),
+};
+
+const asyncWrapper = {
+  getItem: jest.fn(() => Promise.resolve(JSON.stringify({ key1: 'value1' }))),
+  setItem: jest.fn(() => Promise.resolve()),
+  removeItem: jest.fn(() => Promise.resolve()),
+};
+
+test.each([
+  [syncWrapper],
+  [asyncWrapper],
+])('storageAdapter', async (wrapper) => {
+
+  const storage = storageAdapter(loggerMock, 'prefix', wrapper);
+
+  await storage.load!();
+
+  expect(wrapper.getItem).toHaveBeenCalledWith('prefix');
+
+  expect(storage.length).toBe(1);
+  expect(storage.key(0)).toBe('key1');
+  expect(storage.getItem('key1')).toBe('value1');
+
+  storage.setItem('key2', 'value2');
+  expect(storage.getItem('key2')).toBe('value2');
+  expect(storage.length).toBe(2);
+
+  storage.removeItem('key1');
+  expect(storage.getItem('key1')).toBe(null);
+  expect(storage.length).toBe(1);
+
+  await storage.save!();
+  expect(wrapper.setItem).not.toHaveBeenCalled();
+
+  storage.setItem('.till', '1');
+  expect(storage.length).toBe(2);
+  expect(storage.key(0)).toBe('key2');
+  expect(storage.key(1)).toBe('.till');
+
+  await storage.save!();
+  expect(wrapper.setItem).toHaveBeenCalledWith('prefix', JSON.stringify({ key2: 'value2', '.till': '1' }));
+
+  storage.removeItem('.till');
+
+  await storage.save!();
+  expect(wrapper.setItem).toHaveBeenCalledWith('prefix', JSON.stringify({ key2: 'value2' }));
+
+  await storage.save!();
+  expect(wrapper.setItem).toHaveBeenCalledTimes(2);
+});

src/storages/inLocalStorage/storageAdapter.ts

@@ -10,23 +10,29 @@ function isTillKey(key: string) {
 export function storageAdapter(log: ILogger, prefix: string, wrapper: SplitIO.StorageWrapper): StorageAdapter {
   let cache: Record<string, string> = {};
 
-  let connectPromise: Promise<void> | undefined;
-  let disconnectPromise = Promise.resolve();
+  let loadPromise: Promise<void> | undefined;
+  let savePromise = Promise.resolve();
+
+  function _save() {
+    return savePromise = savePromise.then(() => {
+      return Promise.resolve(wrapper.setItem(prefix, JSON.stringify(cache)));
+    }).catch((e) => {
+      log.error(LOG_PREFIX + 'Rejected promise calling wrapper `setItem` method, with error: ' + e);
+    });
+  }
 
   return {
     load() {
-      return connectPromise || (connectPromise = Promise.resolve(wrapper.getItem(prefix)).then((storedCache) => {
+      return loadPromise || (loadPromise = Promise.resolve().then(() => {
+        return wrapper.getItem(prefix);
+      }).then((storedCache) => {
         cache = JSON.parse(storedCache || '{}');
       }).catch((e) => {
-        log.error(LOG_PREFIX + 'Rejected promise calling storage getItem, with error: ' + e);
+        log.error(LOG_PREFIX + 'Rejected promise calling wrapper `getItem` method, with error: ' + e);
       }));
     },
     save() {
-      return disconnectPromise = disconnectPromise.then(() => {
-        return Promise.resolve(wrapper.setItem(prefix, JSON.stringify(cache))).catch((e) => {
-          log.error(LOG_PREFIX + 'Rejected promise calling storage setItem, with error: ' + e);
-        });
-      });
+      return savePromise;
     },
 
     get length() {
@@ -40,11 +46,11 @@ export function storageAdapter(log: ILogger, prefix: string, wrapper: SplitIO.St
     },
     removeItem(key: string) {
       delete cache[key];
-      if (isTillKey(key)) this.save!();
+      if (isTillKey(key)) _save();
     },
     setItem(key: string, value: string) {
       cache[key] = value;
-      if (isTillKey(key)) this.save!();
+      if (isTillKey(key)) _save();
     }
   };
 }