How long does it take for the data to be reflected once A/B test is initiated?

A/B tests will only start to show results in the dashboard from around 24 hours after they have been initiated, as it takes a while to begin collecting data. You should therefore begin to see results within the dashboard shortly. 

Please note though in our doc: https://www.algolia.com/doc/guides/ab-testing/what-is-ab-testing/how-to/create-and-run-an-ab-test/#view-the-results it mentions that test results are updated every 5 minutes. This is true for the existing A/B test but not first time initiating it.