[Tests-Only] Improve acceptance test error handling

[phil-davis]

Description

When I run the toImplementOnOCIS oC10 API tests on OCIS, there are lots of failures - which is expected. Those test scenarios are for things that are (mostly) not yet implemented on OCIS.

But in many places the failure message is not helpful.

Improve the error handling so that more helpful test failure messages are emitted.

Related Issue

owncloud/ocis-reva#415

How Has This Been Tested?

CI
owncloud/ocis-reva#460

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Database schema changes (next release will require increase of minor version instead of patch)
• Breaking change (fix or feature that would cause existing functionality to change)
• Technical debt
• Tests only (no source changes)

Checklist:

• Code changes
• Unit tests added
• Acceptance tests added
• Documentation ticket raised:
• Changelog item, see TEMPLATE

[codecov]

Codecov Report

Merging #37868 into master will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             master   #37868   +/-   ##
=========================================
  Coverage     64.75%   64.75%           
  Complexity    19403    19403           
=========================================
  Files          1285     1285           
  Lines         75819    75819           
  Branches       1336     1336           
=========================================
  Hits          49096    49096           
  Misses        26329    26329           
  Partials        394      394           

Flag	Coverage Δ	Complexity Δ
#javascript	54.06% <ø> (ø)	0.00 <ø> (ø)
#phpunit	65.93% <ø> (ø)	19403.00 <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

---

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 4905f54...dd21bae. Read the comment docs.