Print out widget tree in Flutter test

Question

In Flutter, how can I print out the current widget tree in a widget unit test, in order to understand the current state of the UI for debugging?

(For example, in React/Ensyme, I could use debug(). Is there something comparable in Flutter?)

score 19 · Accepted Answer · answered Oct 27 '19 at 13:01

19

This will print the widget tree based on the Diagnosticable interface, which both Widget, RenderObject and Element implements.

Note that for custom made widgets, you'll have to implement a method for their content to display in that tree: debugFillProperties

answered Oct 27 '19 at 13:01

Rémi Rousselet

Looks promising, unfortunately it just throws an exception when I call it: https://gist.github.com/mdr/915a269a6a314d49f90041736480c5a4 – Matt R Oct 28 '19 at 07:59
2

Consider making an issue. That assert is very unclear. – Rémi Rousselet Oct 28 '19 at 08:41
By elimination, looks to be a problem in some of the theme customisation I was using. I will try and make a minimum reproducible test case and submit it as a bug. But otherwise, that works a treat, thanks! – Matt R Nov 05 '19 at 18:25

1 Answers1