WCST_Import error with mock:true for map_mosaic recipe

[Bang Pham Huu]

with this ingredient file:
{
  "config": {
    "service_url": "http://localhost:8080/rasdaman/ows",
    "tmp_directory": "/tmp/",
    "default_crs": "http://opengis.net/def/OGC/0/Index2D",
    "mock": true,
    "track_files": false,
    "automated": true
  },
  "input": {
    "coverage_id": "TestCoverage03",
    "paths": [
      "*.tif"
    ]
  },
  "recipe": {
    "name": "map_mosaic",
    "options": {
		"wms_import": true
    }
  }
}

returns error

File 'mean_summer_airtemp_4326_resized.tif' with size 0.04 MB; Total time to ingest 0.01s @ 4.0 MB/s.

This is just a mocked request, no data will be changed. 
http://localhost:8080/rasdaman/ows?service=WMS&version=1.3.0&request=GetCapabilities
Exception thrown when importing in WMS. Please try to reimport in WMS manually.
An error has occured in the execution of the program. Error Message: can only parse strings
Stack Trace: Traceback (most recent call last):
  File "/home/rasdaman/rasdaman_community/install/share/rasdaman/wcst_import/wcst_import.py", line 130, in main
    reg.run_recipe(session)
  File "/home/rasdaman/rasdaman_community/install/share/rasdaman/wcst_import/master/recipe/recipe_registry.py", line 80, in run_recipe
    recipe.run()
  File "/home/rasdaman/rasdaman_community/install/share/rasdaman/wcst_import/master/recipe/base_recipe.py", line 103, in run
    self.ingest()
  File "/home/rasdaman/rasdaman_community/install/share/rasdaman/wcst_import/recipes/map_mosaic/recipe.py", line 93, in ingest
    importer.ingest()
  File "/home/rasdaman/rasdaman_community/install/share/rasdaman/wcst_import/master/importer/importer.py", line 79, in ingest
    self._insert_update_into_wms()
  File "/home/rasdaman/rasdaman_community/install/share/rasdaman/wcst_import/master/importer/importer.py", line 354, in _insert_update_into_wms
    raise e
ValueError: can only parse strings