Guard tifffile import with pytest.importorskip on #1635

Matches the convention used elsewhere in xrspatial/geotiff/tests/.
Test module no longer hard-fails collection on machines without
tifffile installed.

Author: brendancol

xrspatial/geotiff/tests/test_user_defined_crs_wkt_1632.py

@@ -20,7 +20,7 @@
 import pytest
 import xarray as xr
 
-import tifffile
+tifffile = pytest.importorskip("tifffile")
 
 from xrspatial.geotiff import open_geotiff, to_geotiff
 from xrspatial.geotiff._geotags import _looks_like_wkt