[BUG][Python-Flask] Unit tests: Missing snake_case vs. camelCase/PascalCase conversion on path parameters

Description

We have an OpenAPI 3.0 spec file with parameterized paths. The path parameters are defined as camelCase.
When generating Python unit tests (place-holders) for python-flask:
the test_*.py files format the request path as:

'/data/{remoteId}'.format(remote_id=56)

Execution of the tests gives us an error:

python3 -m openapi_server.test.test_default_controller

Returns:

E
======================================================================
ERROR: test_data_remote_id_get (__main__.TestDefaultController)
Test case for data_remote_id_get
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/tom/issues/python-flask-pythonic-params/openapi_server/test/test_default_controller.py", line 21, in test_data_remote_id_get
    '/data/{remoteId}'.format(remote_id=56),
KeyError: 'remoteId'

----------------------------------------------------------------------
Ran 1 test in 0.018s

FAILED (errors=1)

openapi-generator version

I used OpenAPI generator CLI version 4.0.0-SNAPSHOT:
https://oss.sonatype.org/content/repositories/snapshots/org/openapitools/openapi-generator-cli/4.0.0-SNAPSHOT/openapi-generator-cli-4.0.0-20181210.103357-85.jar

OpenAPI declaration file content or url

See python-flask-pythonic-params.yaml in the attached zip-file:
python-flask-pythonic-params.zip

Command line used for generation

java -jar openapi-generator-cli-4.x.jar generate -i ./python-flask-pythonic-params.yaml -g python-flask -o ./python-flask-pythonic-params/

Steps to reproduce

1. Generate the server code

   ./python-flask-pythonic-params.sh
   

2. Run the unit test

   (cd python-flask-pythonic-params && python3 -m openapi_server.test.test_default_controller)

Related issues/PRs

• #1671

Suggest a fix

Either:

• (recommended) Change the path parameter to a pythonic equivalent (i.e. snake_case)
• Change format() parameter name to camelCase

Start by generating the server from python-flask-pythonic-params.yaml with the documented command, then inspect openapi_server/test/test_default_controller.py and run its test module. The work is done when the generated path-parameter formatting handles the camelCase remoteId consistently and the reproduced unit test completes without a KeyError.