add support for Sinon-decorated properties

src/SequelizeSimpleCache.js

@@ -53,16 +53,21 @@ class SequelizeSimpleCache {
             }
           }
           const promise = target[prop](...args);
-          assert(promise.then, `${name}.${prop} did not return a promise`);
+          assert(promise.then, `${name}.${prop}() did not return a promise but should`);
           return promise.then((data) => {
             if (data !== undefined && data !== null) {
               this.cache.set(hash, { data, expires: Date.now() + ttl * 1000, type: name });
             }
             return Promise.resolve(data); // resolve from database
           });
         };
-        fn.restore = () => target[prop].restore(); // TODO: Sinon support
-        return fn;
+        return new Proxy(fn, { // support Sinon-decorated properties
+          get: (_, deco) => { // eslint-disable-line consistent-return
+            if (Reflect.has(target, prop) && Reflect.has(target[prop], deco)) {
+              return target[prop][deco]; // e.g., `User.findOne.restore`
+            }
+          },
+        });
       },
     };
     return new Proxy(model, interceptor);

test/SequelizeSimpleCache.spec.js

@@ -287,7 +287,7 @@ describe('SequelizeSimpleCache', () => {
     expect(stubConsoleDebug.called).to.be.false;
   });
 
-  it('should work to stub models using Sinon in unit tests / restore variant 1', async () => {
+  it('should work to stub models using Sinon in unit tests / option 1', async () => {
     const model = {
       name: 'User',
       findOne: async () => ({ username: 'fred' }),
@@ -303,19 +303,19 @@ describe('SequelizeSimpleCache', () => {
     stub.restore();
   });
 
-  it('should work to stub models using Sinon in unit tests / restore variant 2', async () => {
+  it('should work to stub models using Sinon in unit tests / option 2', async () => {
     const model = {
       name: 'User',
       findOne: async () => ({ username: 'fred' }),
     };
     const cache = new SequelizeSimpleCache({ User: {} });
     const User = cache.init(model);
-    const stub = sinon.stub(User, 'findOne').resolves({ username: 'foo' });
+    sinon.stub(User, 'findOne').resolves({ username: 'foo' });
     const result1 = await User.findOne({ where: { username: 'foo' } });
     const result2 = await User.findOne({ where: { username: 'foo' } });
     expect(result1).to.be.deep.equal({ username: 'foo' });
     expect(result2).to.be.deep.equal({ username: 'foo' });
-    expect(stub.calledOnce).to.be.true;
+    expect(User.findOne.calledOnce).to.be.true;
     User.findOne.restore();
   });
 });