Update test suite to improve coverage

[dchaddock]

We've introduced a lot of new functionality lately, so we'll do a detailed review of the test suite to make sure that we're covering as many things as we can that's reasonable.

[dchaddock]

Note - coverage is currently at 91%.

$ poetry run coverage report --show-missing
Name                                                    Stmts   Miss  Cover
---------------------------------------------------------------------------
pyaurorax/__init__.py                                      18      0   100%
pyaurorax/_internal/__init__.py                             0      0   100%
pyaurorax/_internal/util.py                                 4      2    50%
pyaurorax/api/__init__.py                                  11      0   100%
pyaurorax/api/api.py                                       16      2    88%
pyaurorax/api/classes/__init__.py                           0      0   100%
pyaurorax/api/classes/request.py                           72     18    75%
pyaurorax/api/classes/response.py                          11      2    82%
pyaurorax/api/classes/urls.py                              87      0   100%
pyaurorax/availability/__init__.py                          7      0   100%
pyaurorax/availability/availability.py                     22      0   100%
pyaurorax/availability/classes/__init__.py                  0      0   100%
pyaurorax/availability/classes/availability_result.py      10      1    90%
pyaurorax/conjunctions/__init__.py                         12      0   100%
pyaurorax/conjunctions/classes/__init__.py                  0      0   100%
pyaurorax/conjunctions/classes/conjunction.py              17      2    88%
pyaurorax/conjunctions/classes/search.py                  115      7    94%
pyaurorax/conjunctions/conjunctions.py                     38     11    71%
pyaurorax/data_products/__init__.py                        15      0   100%
pyaurorax/data_products/classes/__init__.py                 0      0   100%
pyaurorax/data_products/classes/data_product.py            40     11    72%
pyaurorax/data_products/classes/search.py                  77      4    95%
pyaurorax/data_products/data_products.py                   91     24    74%
pyaurorax/ephemeris/__init__.py                            10      0   100%
pyaurorax/ephemeris/classes/__init__.py                     0      0   100%
pyaurorax/ephemeris/classes/ephemeris.py                   45      2    96%
pyaurorax/ephemeris/classes/search.py                      79      5    94%
pyaurorax/ephemeris/ephemeris.py                           78     19    76%
pyaurorax/exceptions.py                                    30      1    97%
pyaurorax/location.py                                      14      1    93%
pyaurorax/metadata/__init__.py                              4      0   100%
pyaurorax/metadata/metadata.py                             21      5    76%
pyaurorax/requests/__init__.py                              4      0   100%
pyaurorax/requests/requests.py                             63     10    84%
pyaurorax/sources/__init__.py                              20      0   100%
pyaurorax/sources/classes/__init__.py                       0      0   100%
pyaurorax/sources/classes/data_source.py                   47      9    81%
pyaurorax/sources/classes/data_source_stats.py             15      1    93%
pyaurorax/sources/sources.py                               98     13    87%
pyaurorax/util/__init__.py                                  4      0   100%
pyaurorax/util/calculate_btrace.py                         31      6    81%
tests/conftest.py                                          43     14    67%
tests/test_suite/__init__.py                                0      0   100%
tests/test_suite/accounts/test_accounts.py                  8      0   100%
tests/test_suite/availability/test_availability.py         20      0   100%
tests/test_suite/conjunctions/test_conjunctions.py        220      7    97%
tests/test_suite/data_products/test_data_products.py      170      7    96%
tests/test_suite/ephemeris/test_ephemeris.py              150     14    91%
tests/test_suite/exceptions/test_exceptions.py             83      1    99%
tests/test_suite/location/test_location.py                 14      0   100%
tests/test_suite/metadata/test_metadata.py                 24      0   100%
tests/test_suite/requests/test_requests.py                 37      0   100%
tests/test_suite/sources/test_sources.py                   88      5    94%
tests/test_suite/test_version.py                            3      0   100%
tests/test_suite/util/test_btrace.py                       36      0   100%
---------------------------------------------------------------------------
TOTAL                                                    2122    204    90%