[Patch] build tests fails: /Dia/Objects/Transition/ConnectionPoints: ** Dia:ERROR:test-objects.c:529:_test_connectionpoint_consistency: assertion failed: ((cp->directions & DIR_EAST) == 0)

when running:

cd tests
make test

I get:

[...]
/Dia/Objects/Transition/ConnectionPoints: **
Dia:ERROR:test-objects.c:529:_test_connectionpoint_consistency: assertion failed: ((cp->directions & DIR_EAST) == 0)
Makefile:845: die Regel für Ziel „test“ scheiterte
make: *** [test] Abgebrochen

This here is:

-- System Information:
Debian Release: 9.4
  APT prefers stable
  APT policy: (500, 'stable')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 4.9.0-6-amd64 (SMP w/8 CPU cores)
Locale: LANG=de_CH.utf8, LC_CTYPE=de_CH.utf8 (charmap=UTF-8), LANGUAGE=de_CH:de (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages dia depends on:
ii  dia-common           0.97.3+git20180422-0.1
ii  libart-2.0-2         2.3.21-2
ii  libatk1.0-0          2.22.0-1
ii  libc6                2.24-11+deb9u3
ii  libcairo2            1.14.8-1
ii  libfontconfig1       2.11.0-6.7+b1
ii  libfreetype6         2.6.3-3.2
ii  libgdk-pixbuf2.0-0   2.36.5-2+deb9u2
ii  libglib2.0-0         2.50.3-2
ii  libgtk2.0-0          2.24.31-2
ii  libpango-1.0-0       1.40.5-1
ii  libpangocairo-1.0-0  1.40.5-1
ii  libpangoft2-1.0-0    1.40.5-1
ii  libpng16-16          1.6.28-1
ii  libpython2.7         2.7.13-2+deb9u2
ii  libxml2              2.9.4+dfsg1-2.2+deb9u2
ii  libxslt1.1           1.1.29-2.1
ii  zlib1g               1:1.2.8.dfsg-5

Versions of packages dia recommends:
ii  dia-shapes   0.6.0-3
ii  gsfonts-x11  0.24