I want to move appart from the selenium control flow in my Protractor tests.
Here are the steps and problems I went through so far:
1. Disable it test by test
My first idea was to use SELENIUM_PROMISE_MANAGER in order to move from selenium promises to async/await code.
Unfortunately, I found no way to put one test to SELENIUM_PROMISE_MANAGER=0 while keeping others to SELENIUM_PROMISE_MANAGER=1 in order to do the migration smoothly.
2. Keep it but use async/await too
So I thought about a code using async/await while keeping SELENIUM_PROMISE_MANAGER=1.
Unfortunately it seems not to be compatible: https://github.com/angular/protractor/tree/master/exampleTypescript/asyncAwait
There is nothing about such issue on Selenium side so I am wondering if this is an advice or a real it always fails.
3. Override promise.USE_PROMISE_MANAGER
Using protractor.promise.USE_PROMISE_MANAGER=false does not work for me (in beforeEach).
4. Call the control flow on async code
protractor.promise.controlFlow().execute(/* my async code*/);
For me it seems to mix async/await to control flow...
What is the right strategy?
I am wondering, what is the right strategy to move to async/await in Protractor tests?
I don't want to put everything in async/await in one change but to spread the change in multiple small changes
Incompatible, because
Read all about in this issue here.
As it's very technical, the way I (as relatively untechnical guy) understood it, is that jasminewd2, protractor and webDriver incl. ControlFlow are not designed to handle a mix of native promises and managed promises. It handle only managed promises and such are created by many jasminewd2-commands. However, async/await creates native promises and pushes it into the ControlFlow, which ends in a mix of both promises type and it all ends up with heavy timing issues. It can't be resolved as the ControlFlow works as expected and as it was designed for. The situation with async/await was never part of the ControlFlow design.
Switching off the ControlFlow to me means, managed promises get ignored. But because of async/await any managed promise would be wrapped inside a native promise and therefore it doesn't matter, that managed promises get ignored as you keep track of all asynchronous tasks already by tracking native promises only.
How to test both, migrated and not yet migrated test cases
Create two separate conf.js (or whatever your config file is named) and keep them separated. If you have common parts, i.e. helper functions, also migrate those and potentially keep the un-migrated as a duplicate as well. (create to .js-files or use a boolean-indicator to execute either or)
@DubZzz found a possible trick to move smoothly to async / await. His trick is to convert helpers using async / await and call them in protractor.promise.controlFlow().execute. Then move test by test and finally remove controlFlow execute and flag.
For Migration these links I can provide:
The official introduction and migration guide
A similar question witha well documented answer
A good blog about async/await and promises
The official thread about deprecate promise Manager. It also contains helpful information in how to make async/await work.