Fix #418: Improve test for Portal Config schema

[tomschr]

This PR contains invalid and valid test cases of Portal Config XML files.

[github-actions]

Coverage Report

For commit 66c3cd7

Click to expand Coverage Report

  Name                                        Stmts   Miss Branch BrPart  Cover
  -----------------------------------------------------------------------------
+ src/docbuild/tasks/portal.py                  140      0     50      1  99.5%
+ src/docbuild/tasks/metadata/runner.py          85      0     32      1  99.1%
+ src/docbuild/models/manifest.py               152      1     30      1  98.9%
+ src/docbuild/logging.py                       104      1     26      1  98.5%
+ src/docbuild/utils/pidlock.py                  79      1     14      1  97.8%
+ src/docbuild/cli/cmd_portal/cmd_list.py       139      0     66      5  97.6%
+ src/docbuild/cli/cmd_config/list.py            26      0      8      1  97.1%
+ src/docbuild/models/deliverable/view.py       175      3     48      6  96.0%
+ src/docbuild/config/xml/list.py                32      1     16      1  95.8%
+ src/docbuild/cli/callback.py                   35      0     10      2  95.6%
+ src/docbuild/cli/cmd_cli.py                   113      3     16      3  95.3%
+ src/docbuild/utils/concurrency.py              65      3     18      1  95.2%
+ src/docbuild/cli/cmd_metadata/__init__.py      41      2      4      2  91.1%
- src/docbuild/cli/cmd_doctor.py                 37      4     10      2  87.2%
- src/docbuild/tasks/metadata/manifest.py       102     14     34      5  81.6%
- src/docbuild/cli/cmd_config/validate.py        21      2     12      3  78.8%
- src/docbuild/config/xml/xinclude.py            80     13     28      9  77.8%
- src/docbuild/cli/cmd_build/__init__.py         15      5      0      0  66.7%
- src/docbuild/cli/cmd_check/__init__.py         22      9      4      0  50.0%
- src/docbuild/utils/sysdeps.py                  83     54     28      1  27.0%
  -----------------------------------------------------------------------------
+ TOTAL                                        3651    116   1000     46  95.7%
  
  55 files skipped due to complete coverage.