Added tests to improve code coverage

Also reformatted with black. Tests were added for the get_method and diagnostics_info functions in the postprocessing interface. Tests for the discover_diagnostics function will be written once these changes have been merged as then the cookiecutter plugins can then be properly tested.

pysteps/postprocessing/diagnostics.py

@@ -2,13 +2,13 @@
 pysteps.postprocessing.diagnostics
 ====================
 
-Methods for applying postprocessing.
+Methods for diagnostic postprocessing.
 
 The methods in this module implement the following interface::
 
-    postprocess_xxx(optional arguments)
+    diagnostic_xyz(optional arguments)
 
-where **xxx** is the name of the postprocess to be applied.
+where **xyz** is the name of the diagnostic postprocessing to be applied.
 
 Postprocessor standardizations can be specified here if there is a desired input and output format that all should
 adhere to.
@@ -21,51 +21,10 @@
 
 """
 
-try:
-    from osgeo import gdal, gdalconst, osr
 
-    GDAL_IMPORTED = True
-except ImportError:
-    GDAL_IMPORTED = False
+def diagnostics_example1(filename, **kwargs):
+    return "Hello, I am an example postprocessor."
 
-try:
-    import h5py
 
-    H5PY_IMPORTED = True
-except ImportError:
-    H5PY_IMPORTED = False
-
-try:
-    import metranet
-
-    METRANET_IMPORTED = True
-except ImportError:
-    METRANET_IMPORTED = False
-
-try:
-    import netCDF4
-
-    NETCDF4_IMPORTED = True
-except ImportError:
-    NETCDF4_IMPORTED = False
-
-try:
-    from PIL import Image
-
-    PIL_IMPORTED = True
-except ImportError:
-    PIL_IMPORTED = False
-
-try:
-    import pyproj
-
-    PYPROJ_IMPORTED = True
-except ImportError:
-    PYPROJ_IMPORTED = False
-
-try:
-    import pygrib
-
-    PYGRIB_IMPORTED = True
-except ImportError:
-    PYGRIB_IMPORTED = False
+def diagnostics_example2(filename, **kwargs):
+    return 42

pysteps/postprocessing/interface.py

@@ -20,7 +20,9 @@
 from pysteps.postprocessing import diagnostics
 from pprint import pprint
 
-_diagnostics_methods = dict()
+_diagnostics_methods = dict(
+    example1=diagnostics.diagnostics_example1, example3=lambda x: [x, x]
+)
 
 
 def discover_diagnostics():
@@ -97,6 +99,8 @@ def diagnostics_info():
     available_diagnostics = set(available_diagnostics)
     diagnostics_in_the_interface = set(diagnostics_in_the_interface)
 
+    available_diagnostics = {s.split("_")[1] for s in available_diagnostics}
+
     difference = available_diagnostics ^ diagnostics_in_the_interface
     if len(difference) > 0:
         print("\nIMPORTANT:")
@@ -145,7 +149,7 @@ def get_method(name, method_type):
         |     Name    |              Description                              |
         +=============+=======================================================+
 
-    method_type: {'diagnostics', diagnostic_diagnostics}
+    method_type: {'diagnostics', diagnostics_name}
             Type of the method (see tables above).
 
     """

pysteps/tests/test_interfaces.py

@@ -360,3 +360,51 @@ def test_tracking_interface():
 
     invalid_names = ["lucas-kanade", "dating"]
     _generic_interface_test(method_getter, valid_names_func_pair, invalid_names)
+
+
+def test_postprocessing_interface():
+    """Test the postprocessing module interface."""
+
+    import pysteps.postprocessing as postprocessing
+    from pysteps.postprocessing import diagnostics_example1
+    from pysteps.postprocessing import diagnostics_example2
+
+    valid_names_func_pair = [("example1", diagnostics_example1)]
+
+    def method_getter(name):
+        return pysteps.postprocessing.interface.get_method(name, "diagnostics")
+
+    invalid_names = ["bom", "fmi", "knmi", "mch", "mrms", "opera", "saf"]
+    _generic_interface_test(method_getter, valid_names_func_pair, invalid_names)
+
+    # Test for invalid argument type
+    with pytest.raises(TypeError):
+        pysteps.postprocessing.interface.get_method("example1", None)
+        pysteps.postprocessing.interface.get_method(None, "diagnostics")
+
+    # Test for invalid method types
+    with pytest.raises(ValueError):
+        pysteps.postprocessing.interface.get_method("example1", "io")
+
+    with pytest.raises(TypeError):
+        pysteps.postprocessing.interface.get_method(24, "diagnostics")
+
+    assert isinstance(
+        pysteps.postprocessing.interface.diagnostics_info()[0],
+        set,
+    )
+
+    assert isinstance(
+        pysteps.postprocessing.interface.diagnostics_info()[1],
+        set,
+    )
+
+    assert isinstance(
+        diagnostics_example1(filename="example_filename"),
+        str,
+    )
+
+    assert isinstance(
+        diagnostics_example2(filename="example_filename"),
+        int,
+    )