Deep-copy objects on MemoryStorage and add tests

src/background/infrastructures/memory-storage.js

@@ -2,10 +2,14 @@ const db = {};
 
 export default class MemoryStorage {
   set(name, value) {
-    db[name] = value;
+    let data = JSON.stringify(value);
+    if (typeof data === 'undefined') {
+      throw new Error('value is not serializable');
+    }
+    db[name] = data;
   }
 
   get(name) {
-    return db[name];
+    return JSON.parse(db[name]);
   }
 }

test/background/infrastructures/memory-storage.test.js

@@ -0,0 +1,41 @@
+import MemoryStorage from 'background/infrastructures/memory-storage';
+
+describe("background/infrastructures/memory-storage", () => {
+  let versionRepository;
+
+  it('stores values', () => {
+    let cache = new MemoryStorage();
+    cache.set('number', 123);
+    expect(cache.get('number')).to.equal(123);
+
+    cache.set('string', '123');
+    expect(cache.get('string')).to.equal('123');
+
+    cache.set('object', { hello: '123' });
+    expect(cache.get('object')).to.deep.equal({ hello: '123' });
+  });
+
+  it('stored on shared memory', () => {
+    let cache = new MemoryStorage();
+    cache.set('red', 'apple');
+
+    cache = new MemoryStorage();
+    let got = cache.get('red');
+    expect(got).to.equal('apple');
+  });
+
+  it('stored cloned objects', () => {
+    let cache = new MemoryStorage();
+    let recipe = { sugar: '300g' };
+    cache.set('recipe', recipe);
+
+    recipe.salt = '20g'
+    let got = cache.get('recipe', recipe);
+    expect(got).to.deep.equal({ sugar: '300g' });
+  });
+
+  it('throws an error with unserializable objects', () => {
+    let cache = new MemoryStorage();
+    expect(() => cache.set('fn', setTimeout)).to.throw();
+  })
+});