Failing Adapter tests in environments with an HTTP proxy

[dvzrv]

Hi! While trying to rebuild 2.3.0 in the context of #550 I ran into a few failing tests (which I am now disabling):

python-geopy-2.3.0-3-x86_64-check.log

[KostyaEsmukov]

Hi! The test failures you're observing in test/adapters/each_adapter.py might be caused by the presence of an HTTP proxy environment variable in your testing environment. In these failing tests this variable gets overshadowed by the dummy proxy server started in the tests. Perhaps the dummy proxy should use the original proxy environment variable too.

For the time being, disabling these tests in downstream packages seems to be okay.

[KostyaEsmukov]

Turns out there is an issue with the httpbin.org service, which seems to be unmaintained now: postmanlabs/httpbin#702

I switched tests to httpbingo.org which I hope will be more stable.

The reason why these tests must do the remote lookups is because they need an https service with a certificate the system CA store trusts. The easiest way to get that is issuing a remote query to the Internet.

Let me add that for downstream packages I recommend running tests with the --skip-tests-requiring-internet option (see #413) to avoid this kind of hustle.