tests: add first approval tests

[matthiasschaub]

• for area calculation choose CRS valid world-wide not just UTM
• Choose threshold for area ratio
• Make approval tests work with parametrized fixtures

Leads to test duplication. Will be fixed in another PR. -> #456

[koebi]

8857 seems to be an okay projection

[matthiasschaub]

Looks good. I am going to use it.

[koebi]

Where does tmp_path_factory come from? Do I just not see it?

[matthiasschaub]

Its pytest magic. Its a global fixture defined by pytest. No import needed.

(The other fixtures are also not imported but defined by us in conftest.py which is discovered and parsed by pytest magic as well)

[matthiasschaub]

test_path_factory gives as a tmp dir unique to the current test run

[matthiasschaub]

For parametrized fixtures in a tests following error gets raised after the first test run (first parameter):

    def test_smt_approver(sketch_map_marked_path, vector_path):
        options = (
            Options()
            .with_reporter(SketchMapToolReporter(sketch_map=sketch_map_marked_path))
            .with_comparator(GeoJSONComparator())
        )
        with open(vector_path, "rb") as f:
>           verify_binary(f.read(), ".geojson", options=options)
E           approvaltests.approval_exception.ApprovalException: We noticed that you called verify more than once in the same test. 
E           This is the second call to verify:
E               approved_file: /home/matthias/work/smt/tests/integration/test_approval.test_smt_approver.approved.geojson
E           
E           By default, ApprovalTests only allows one verify() call per test.
E           To find out more, visit: 
E           https://github.com/approvals/ApprovalTests.Python/blob/main/docs/how_to/multiple_approvals_per_test.md
E           
E           # Possible Fixes
E           1. Separate your test into two tests
E           2. In your verify call, add `options=NamerFactory.with_parameters("your_paramater")`
E           3. In your test, call `approvals.settings().allow_multiple_verify_calls_for_this_method()`