It is my understanding that if I want to do integration testing of Apps for SPO I first and foremost need a tenant to do the testing on. The problem is, how do I run the tests? Ideally I want to use a test runner so that I get reports. But how can a test runner make CSOM-requests to SharePoint Online when it runs outside the app?
You can deploy your app on your local farm for testing purpose then when you feel comfortable you can deploy on your SP Online and do the others tests