C++ tests for schema files: help on how to understand was is tested (in order to work on the generator)

[goto40]

I played around with the C++ generator tests: I started FIXTURE=cplusplus npm test, as described in the README, and some tests are executed.

I am interested in code from schema files. So I "broke" an example integer-float-union.1.json described by integer-float-union.schema in the test folder (I changed the field name). I somehow expected that some test will fail, but everything seems ok.

Are the fixtures also testing the schema examples?
If not - what would be a good starting point to introduce such tests (from the overall design of the tests)?

[goto40]

My bad: I can obviously trigger schema tests with FIXTURE=schema-cplusplus npm test.
But then I get error: QuickTypeError: Could not fetch schema https://raw.githubusercontent.com/quicktype/quicktype/master/test/inputs/schema/list.schema, referred to from .../quicktype/test/inputs/schema/ref-remote.schema# (on my computer). However, I can load the URL successfully with my browser. I will further analyze.

Note: when I run ./script/quicktype --lang cpp test/inputs/schema/ref-remote.schema everything works as expected.