building from source on Ubuntu 18.04 fails

[Yariv Barkan]

Trying to build gtk+3.0-3.22.30 from source fails.
I got the source using package gtk-3-examples.

$ apt policy gtk-3-examples
gtk-3-examples:
  Installed: 3.22.30-1ubuntu3
  Candidate: 3.22.30-1ubuntu3
  Version table:
 *** 3.22.30-1ubuntu3 500
        500 http://il.archive.ubuntu.com/ubuntu bionic-updates/main amd64 Packages
        100 /var/lib/dpkg/status
     3.22.30-1ubuntu1 500
        500 http://il.archive.ubuntu.com/ubuntu bionic/main amd64 Packages

Ubuntu version:
Description: Ubuntu 18.04.2 LTS
Release: 18.04

Steps to reproduce:

apt source gtk-3-examples
sudo apt build-dep gtk-3-examples
sudo apt install devscripts
cd gtk+3.0-3.22.30
debuild -i -us -uc -d -b 2>&1 | tee build.log

The build failed.
First error (to the best of my knowledge):

ERROR:../../../../../testsuite/gtk/scrolledwindow.c:100:test_size: assertion failed (min_size == MIN_SIZE): (153 == 150)
FAIL

Attached is the build log (build.log)

[xalt7x (xalt7x)]

Same with 20.04 (gtk+3.0_3.24.18-1ubuntu1)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[xalt7x (xalt7x)]

On Ubuntu 20.04 I had to add
DEB_BUILD_OPTIONS=nocheck
at the beginning of debian/rules