Change type of error check

Author: mwcraig

src/astro_image_display_api/widget_api_test.py

@@ -99,11 +99,11 @@ def test_offset_by(self, data, wcs):
         self.image.offset_by(10 * u.arcmin, 10 * u.arcmin)
 
         # A mix of pixel and sky should produce an error
-        with pytest.raises(ValueError, match='but dy is of type'):
+        with pytest.raises(u.UnitConversionError, match='are not convertible'):
             self.image.offset_by(10 * u.arcmin, 10)
 
         # A mix of inconsistent units should produce an error
-        with pytest.raises(u.UnitConversionError):
+        with pytest.raises(u.UnitConversionError, match='are not convertible'):
             self.image.offset_by(1 * u.arcsec, 1 * u.AA)
 
     def test_zoom_level(self, data):