pip install sphinx-test-reports.
After that the extension must to be added to the
extensions = ['sphinx_needs', 'sphinxcontrib.test_reports', 'sphinxcontrib.plantuml']
Sphinx-Test-Report is based on the
Therefore it must also be added to the
And same for PlantUML, which is important to render flowcharts for filtered test-cases.
More details can be find in the