cleaned up Time use of netCDF -- it's all in the from_netcdf method now.

gridded/tests/test_time.py

@@ -35,8 +35,8 @@ def test_init_with_timeseries():
 
 
 def test_invalid_timeseries():
-    with pytest.raises(TypeError):
-        t = Time("")
+    with pytest.raises(TypeError, match='not compatible with datetime'):
+        t = Time(data = ["2012-02-03T12:00"])
 
 
 def test_from_netcdf_filename_no_var():

gridded/time.py

@@ -22,6 +22,7 @@ class TimeSeriesError(ValueError):
     """
     pass
 
+
 def offset_as_iso_string(offset_hours):
     """
     returns the offset as an isostring:
@@ -42,6 +43,8 @@ def offset_as_iso_string(offset_hours):
 
 
 def parse_time_offset(unit_str):
+    # NOTE: this uses dateutil -- which isn't otherwise required
+    #       we could write it by hand instead.
     """
     find the time offset from a CF-style time units string.
 
@@ -102,13 +105,6 @@ def __init__(self,
                Allows shifting entire time interval into future or past
         :type displacement: `datetime.timedelta`
         '''
-        # fixme: This should be happening in various from_netcdf methods.
-        # if isinstance(data, (nc4.Variable, nc4._netCDF4._Variable)):
-        #     if (hasattr(nc4, 'num2pydate')):
-        #         self.data = nc4.num2pydate(data[:], units=data.units)
-        #     else:
-        #         self.data = nc4.num2date(data[:], units=data.units, only_use_cftime_datetimes=False, only_use_python_datetimes=True)
-        # elif isinstance(data, Time):
         if isinstance(data, Time):
             self.data = data.data
         elif data is None:
@@ -119,7 +115,11 @@ def __init__(self,
         # Quick check to ensure data is 'datetime-like' enough
         # to be compatible with timedelta operations
         # fixme: add a try:except around this to raise a meaningful error
-        self.data += timedelta(seconds=0)
+
+        try:
+            self.data += timedelta(seconds=0)
+        except TypeError:
+            raise TypeError(f"Time datatype: {self.data.dtype} not compatible with datetime.")
 
         if origin is not None:
             diff = self.data[0] - origin
@@ -166,6 +166,8 @@ def from_netCDF(cls,
                     datavar=None,
                     tz_offset=None,
                     new_tz_offset=None,
+                    origin=None,
+                    displacement=None,
                     **kwargs):
         """
         construct a Time object from a netcdf file.
@@ -226,6 +228,8 @@ def from_netCDF(cls,
                    varname=varname,
                    tz_offset=tz_offset,
                    new_tz_offset=new_tz_offset,
+                   origin=origin,
+                   displacement=displacement,
                    **kwargs
                    )
         return time

gridded/variable.py

@@ -245,23 +245,25 @@ def from_netCDF(cls,
                 units = data.units
             except AttributeError:
                 units = None
-              
+
         if time is None:
             timevarname = Time.locate_time_var_from_var(data)
             if timevarname is None:
-                tdata = None
+                time = Time()
             else:
-                timevar = ds[timevarname]
-                tdata = nc4.num2date(timevar[:], units=timevar.units, only_use_cftime_datetimes=False, only_use_python_datetimes=True)
-            # why isn't this using Time.from_netcdf? (currently doesn't support origin and displacement)
-            time = Time(data=tdata,
+                time = Time.from_netCDF(
                         filename=data_file,
+                        dataset=ds,
                         varname=timevarname,
+                        # datavar=None,
+                        tz_offset=tz_offset,
+                        new_tz_offset=None,
                         origin=time_origin,
-                        displacement=displacement,
-                        tz_offset=tz_offset)
+                        displacement=displacement
+                        )
         else:
             timevarname = 1 if len(time) > 1 else 0
+
         if depth is None:
             istimevar = 0 if timevarname is None else 1
 
@@ -985,19 +987,21 @@ def from_netCDF(cls,
         if time is None:
             timevarname = Time.locate_time_var_from_var(data)
             if timevarname is None:
-                tdata = None
+                time = Time()
             else:
-                timevar = ds[timevarname]
-                tdata = nc4.num2date(timevar[:], units=timevar.units, only_use_cftime_datetimes=False, only_use_python_datetimes=True)
-            # why isn't this using Time.from_netcdf? (currently doesn't support origin and displacement)
-            time = Time(data=tdata,
+                time = Time.from_netCDF(
                         filename=data_file,
+                        dataset=ds,
                         varname=timevarname,
+                        # datavar=None,
+                        tz_offset=tz_offset,
+                        new_tz_offset=None,
                         origin=time_origin,
-                        displacement=displacement,
-                        tz_offset=tz_offset)
+                        displacement=displacement
+                        )
         else:
             timevarname = 1 if len(time) > 1 else 0
+
         if depth is None:
             istimevar = 0 if timevarname is None else 1