Python doctest file to test generation of a WPS request from input arguments.
The specific request involves a "reprojectImage" process submitted to the PML WPS service.

Imports

    >>> from __future__ import (absolute_import, division, print_function)
    >>> from tests.utils import resource_file, compare_xml
    >>> from owslib.wps import WebProcessingService, WPSExecution
    >>> from owslib.etree import etree

Process input/ouutput arguments

    >>> processid = "reprojectImage"
    >>> inputs = [ ("inputImage","http://rsg.pml.ac.uk/wps/testdata/elev_srtm_30m.img"),
    ...            ("outputSRS", "EPSG:4326") ]
    >>> output = "outputImage"

    # build XML request for WPS process execution
    >>> execution = WPSExecution()
    >>> requestElement = execution.buildRequest(processid, inputs, output=output)
    >>> request = etree.tostring( requestElement )

Compare to cached XML request

    >>> _request = open(resource_file('wps_PMLExecuteRequest4.xml'), 'rb').read()
    >>> compare_xml(request, _request)
    True
