install testing app for federation server in CI tests

[individual-it]

Description

testing app is needed also in fed. server

Related Issue

owncloud/QA#580

How Has This Been Tested?

🤖

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Technical debt
• Tests

Checklist:

• Code changes
• Unit tests added
• Acceptance tests added
• Documentation ticket raised:

Open tasks:

• Backport (if applicable set "backport-request" label and remove when the backport was done)

[individual-it]

backport in #32411

[codecov]

Codecov Report

Merging #32410 into master will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             master   #32410   +/-   ##
=========================================
  Coverage        64%      64%           
  Complexity    18578    18578           
=========================================
  Files          1171     1171           
  Lines         69912    69912           
  Branches       1267     1267           
=========================================
  Hits          44746    44746           
  Misses        24796    24796           
  Partials        370      370

Flag	Coverage Δ	Complexity Δ
#javascript	52.84% <ø> (ø)	0 <ø> (ø)	⬇️
#phpunit	65.27% <ø> (ø)	18578 <ø> (ø)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 5e183c2...a1b641d. Read the comment docs.

[individual-it]

closing in favour of #32413

[individual-it]

reopening as discussed in the chat as #32413 has more general issues to be solved

[patrickjahns]

temporary solution - for now 👍