url_helper: dynamically import oauthlib import from inside oauth_headers

oauth_headers is the only function which requires oauthlib, move the
import and ImportError handling inside this function to only attempt
loading at runtime if called. This will allow us to build on platforms
that don't have python-oauthlib installed by default. Add simple unittests
around the missing oauthlib dependencies to make sure the function
performs as intended and raises and NotImplementedError if oauthlib can't
be imported.

1 files changed, 0 insertions, 0 deletions

diff --git a/cloudinit/tests/__init__.py b/cloudinit/tests/__init__.py
new file mode 100644
index 00000000..e69de29b
--- /dev/null
+++ b/cloudinit/tests/__init__.py