Added a function for parsing AllowedValues

[RezwanM]

Overview

This PR fixes #277

Changes:

• Added a helper function for parsing AllowedValues. The problem seemed to be that the attribute allowedValues of the ProcessDescription object was being parsed by OWSLib as a Python set, which is inherently unordered. Parsing the element AllowedValues directly from raw XML into a list ensures the original order of items in AllowedValues is preserved.

Related Issue / Discussion

Additional Information

Links to other issues or sources.

[Zeitsperre]

I'm wondering now whether the issue with the list of values is here or is deeper within OWSLib.

[RezwanM]

Hi, @Zeitsperre. I added some changes which addresses the issues you mentioned above. However, the tests are failing due to a ConnectionError.

[cehbrecht]

@RezwanM @Zeitsperre just come comments:

• could this instead be fixed in owslib itself? It looks like it needs an extra call to fill the allowed values as expected.
• maybe add a test.

[RezwanM]

@cehbrecht @Zeitsperre

• From my findings, the attribute allowedValues of the ProcessDescription object was being parsed by OWSLib as a Python set, which is inherently unordered. Parsing the element AllowedValues directly from raw XML into a list ensures the original order of items in AllowedValues is preserved. I could be wrong, but this seems like the only way to me.
• I added a unit test for checking the order of AllowedValues.

[huard]

I'm confused why this is necessary. In my recollection, WPSClient._processes is a dict with the output of describeprocess, so isn't _process exactly the same as process ?