def test_bad_areas_diff(self):
"""Test that a difference where resolutions are different fails."""
from satpy.composites import DifferenceCompositor, IncompatibleAreas
comp = DifferenceCompositor(name='diff')
# too many arguments
self.assertRaises(ValueError, comp, (self.ds1, self.ds2, self.ds2_big))
# different resolution
self.assertRaises(IncompatibleAreas, comp, (self.ds1, self.ds2_big))
def test_basic_diff(self):
"""Test that a basic difference composite works."""
from satpy.composites import DifferenceCompositor
comp = DifferenceCompositor(name='diff')
res = comp((self.ds1, self.ds2))
np.testing.assert_allclose(res.values, -2)