QGIS Processing Test model with EnMAP-Box algorithms

[jakimowb]

As discussed in personal meeting, we like to show that EnMAP-Box algorithms and processing models created in QGIS can also be used in HPC / server processing environments (no GUI, but many CPUs, e.g. https://portal.azimuth.cms.hu-berlin.de/). Therefore we need an exemplary QgsProcessingModel that can be used in, for example, unit tests and by other scripts that demonstrate the use of QGIS / EnMAP-Box processing models.

1. Create an exemplary QgsProcessingModel that uses multiple QgsProcessingAlgorithms from the EnMAP-Box provider. For example a workflow that imports EnMAP images and applies a classification model on it. (multiple raster inputs and outputs would be nice.

2. Save the model in *.model3 XML (https://docs.qgis.org/3.34/en/docs/user_manual/processing/modeler.html#saving-and-loading-models). I think it's good if it could become part of the standard EnMAP-Box testdata suite.

[janzandr]

Do we want to use actual algorithms to build the test model? Or shall we rather have some test algorithms that we combine to a test model? I would prefere the second option, because it is saver. Using actual algorithms would break the model, every time we change the algorithms.

[jakimowb]

Probably the first option is better, as it shows a "real" use-case. As long as neither the algorithm id's change, nor the required inputs, I don't see a problem here. Shouldn't our processing algorithms be that stable meanwhile?

[janzandr]

Alright, let's start with a simple L2 import: https://raw.githubusercontent.com/EnMAP-Box/enmap-box/948-qgis-processing-test-model-with-enmap-box-algorithms/tests/testdata/processing/importEnmapL2.model3

[janzandr]

Here is a tests for the model: _enmap-box\tests\enmap-box\enmapboxprocessing\testcustomModel.py