chore: fix promisify helper (#16544)

* chore: fix promise deprecation helper

* fix deprecations

* update deprecation tests

spec/api-session-spec.js

@@ -266,12 +266,13 @@ describe('session module', () => {
           }
           expect(error).to.be.undefined(error)
         })
+
         it('with callbacks', (done) => {
           const name = 'foo'
           const value = 'bar'
           const { cookies } = session.defaultSession
 
-          cookies.set({ url, name, value }, error => {
+          cookies.set({ url, name, value }, (error) => {
             if (error) return done(error)
             cookies.flushStore(error => done(error))
           })
@@ -279,6 +280,19 @@ describe('session module', () => {
       })
     })
 
+    describe('ses.cookies.flushStore(callback)', () => {
+      it('flushes the cookies to disk and invokes the callback when done', (done) => {
+        session.defaultSession.cookies.set({
+          url: url,
+          name: 'foo',
+          value: 'bar'
+        }, (error) => {
+          if (error) return done(error)
+          session.defaultSession.cookies.flushStore(() => done())
+        })
+      })
+    })
+
     it('should survive an app restart for persistent partition', async () => {
       const appPath = path.join(__dirname, 'fixtures', 'api', 'cookie-app')
       const electronPath = remote.getGlobal('process').execPath
@@ -735,7 +749,7 @@ describe('session module', () => {
     })
   })
 
-  describe('ses.setCertificateVerifyProc(callback)', () => {
+  describe('ses.setCertificateVerifyProc(callback)', (done) => {
     let server = null
 
     beforeEach((done) => {