tests/newsletter: check that not choosing project does give an error …

[fuzzylogic2000]

…instead of 500

I wanted to properly check that

a4-meinberlin/meinberlin/apps/newsletters/forms.py

Line 48 in 2ef5414

self.add_error('project', _('Select a Project'))

gives a FieldError when there is no project added. But when posting, the error is just added to the error list in the content. So, this checks that we stay on the form page instead of getting a redirect like when successfull form submit. Should still be fine to test that it does not yet work in a+ liqd/adhocracy-plus#1737

[github-actions]

Coverage report

Total coverage

Status	Category	Percentage	Covered / Total
🔴	Statements	9.11%	162/1779
🔴	Branches	6.95%	67/964
🔴	Functions	9.01%	50/555
🔴	Lines	13.15%	677/5150

Status of coverage: 🟢 - ok, 🟡 - slightly more than threshold, 🔴 - under the threshold

Report generated by 🧪jest coverage report action from 76fdcd5

[goapunk]

super cool!