Fix test_checklicense_api

[rtgdk]

Fixing #530

Had some free time, trying to make all tests run successfully - both locally and via PyCharm.
PyCharm debugger is very helpful to fix these issues faster.
Will be fixing more tests in app/tests.py as well.

• Fixed test_checklicense_api where response structure changed
• Fixed core.py with proper exception handling

Now only 2 tests in api are failing - both with rdf file

@goneall Has there been any change with verifying RDF files. Both the remaining tests are failing as an exception is raised by verifyclass.verify JVM call to verify RDF files - 'org.spdx.library.model.SpdxIdInUseException: Can not create Apache-2.0. It is already in use with type License which is incompatible with type ListedLicense')

[rtgdk]

@goneall Is there a better RDF file we can use for tests? The current one - https://github.com/spdx/spdx-online-tools/blob/main/src/examples/SPDXRdfExample-v2.0.rdf - raise issues like 'org.spdx.library.model.SpdxIdInUseException: Can not create Apache-2.0. It is already in use with type License which is incompatible with type ListedLicense'). Tried with this 2.1 version as well but same issue - https://github.com/spdx/tools/blob/master/Examples/SPDXRdfExample-v2.1.rdf

[goneall]

@goneall Is there a better RDF file we can use for tests? The current one - https://github.com/spdx/spdx-online-tools/blob/main/src/examples/SPDXRdfExample-v2.0.rdf - raise issues like 'org.spdx.library.model.SpdxIdInUseException: Can not create Apache-2.0. It is already in use with type License which is incompatible with type ListedLicense'). Tried with this 2.1 version as well but same issue - https://github.com/spdx/tools/blob/master/Examples/SPDXRdfExample-v2.1.rdf

The test files in the tools-java repo should work - as long as we're using the same version of the java tools.

BTW - I'll be offline for the next 3 days or so, so may be a bit slow to respond.

[rtgdk]

@goneall Thanks for the help! The new files worked perfectly! Now all the tests in api are passing, except one which is getting skipped. Will try to run that too after setting up test repos for submit license tool.