After the upgrade to Flutter 1.20.1 none of my widget tests worked anymore. On investigation I found that my widgets weren’t getting rendered at all, i.e. their build method wasn’t being called. This is a preliminary result but I was doing this in my test: Seems like that no longer works and must now be: I haven’t seen anything in the release notes that suggests this should be required. I’m still investigating but in case this helps someone else I thought I’d put it out there.