Increase Test Coverage

[rnjudge]

Problem Statement Currently, the test coverage for Tern's code is 63%. See below, which is a full coverage run on Tern's code base.

$ coverage run -m unittest discover -s tests
$ coverage report --fail-under 85

Name                                      Stmts   Miss  Cover
-------------------------------------------------------------
tern/__init__.py                              0      0   100%
tern/__main__.py                             88     58    34%
tern/analyze/__init__.py                      0      0   100%
tern/analyze/common.py                      247    213    14%
tern/analyze/docker/__init__.py               0      0   100%
tern/analyze/docker/analyze.py               99     79    20%
tern/analyze/docker/container.py            105     57    46%
tern/analyze/docker/dockerfile.py           108     57    47%
tern/analyze/docker/helpers.py              103     79    23%
tern/analyze/docker/run.py                   93     74    20%
tern/analyze/passthrough.py                  44     31    30%
tern/classes/__init__.py                      0      0   100%
tern/classes/command.py                      74      7    91%
tern/classes/docker_image.py                105     16    85%
tern/classes/image.py                        75     13    83%
tern/classes/image_layer.py                 103      5    95%
tern/classes/notice.py                       32      0   100%
tern/classes/notice_origin.py                44      0   100%
tern/classes/origins.py                      31      0   100%
tern/classes/package.py                      71      1    99%
tern/classes/template.py                      9      0   100%
tern/command_lib/__init__.py                  0      0   100%
tern/command_lib/command_lib.py             158    122    23%
tern/report/__init__.py                       0      0   100%
tern/report/content.py                       46     37    20%
tern/report/errors.py                        33      0   100%
tern/report/formats.py                       47      0   100%
tern/report/report.py                        84     55    35%
tern/utils/__init__.py                        0      0   100%
tern/utils/cache.py                          38     24    37%
tern/utils/constants.py                      19      0   100%
tern/utils/general.py                        86     20    77%
tern/utils/rootfs.py                        164     74    55%
tests/test_analyze_docker_dockerfile.py      48      1    98%
tests/test_class_command.py                  84      1    99%
tests/test_class_docker_image.py             48      5    90%
tests/test_class_image.py                    62      1    98%
tests/test_class_image_layer.py              74      1    99%
tests/test_class_notice.py                   38      1    97%
tests/test_class_notice_origin.py            48      1    98%
tests/test_class_origins.py                  60      1    98%
tests/test_class_package.py                 100      1    99%
tests/test_class_template.py                 37      1    97%
tests/test_fixtures.py                       41      0   100%
tests/test_util_general.py                   23      1    96%
-------------------------------------------------------------
TOTAL                                      2769   1037    63%

Describe the Proposal More tests need to be written for Tern. Ideally we would have a coverage for 85% of the code, although, this is up for debate. (I think 80% could be acceptable).

Steps to Implement Proposal Look at files with low % coverage and add tests for them. This will likely not happen all in one PR. Once coverage is up to an acceptable passing rate, merge in PR #530 and re-add the test for GH Actions.

[PrajwalM2212]

We can add this as a GSoC stretch goal. There is a chance that the current ideas can be completed and still have time left during GSoC.

[zoek1]

Working on this right now! :muscle:

[zoek1]

Should i submit a PR per element (cache, files, packages, metadata) or group allof them in one PR? I prefer first option to allow me progress in others test in case some testcase needs more work or isn't valid.