Refactor test to reduce code duplication.

satpy/tests/test_modifiers.py

@@ -159,21 +159,24 @@ def test_imcompatible_areas(self, sunz_ds2, sunz_sza):
 class TestSunZenithReducer:
     """Test case for the sun zenith reducer."""
 
-    def test_basic_default_provided(self, sunz_ds1, sunz_sza):
-        """Test default settings with sza data available."""
+    @classmethod
+    def setup_class(cls):
+        """Initialze SunZenithReducer classes that shall be tested."""
         from satpy.modifiers.geometry import SunZenithReducer
-        comp = SunZenithReducer(name='sza_reduction_test_default', modifiers=tuple())
-        res = comp((sunz_ds1, sunz_sza), test_attr='test')
+        cls.default = SunZenithReducer(name='sza_reduction_test_default', modifiers=tuple())
+        cls.custom = SunZenithReducer(name='sza_reduction_test_custom', modifiers=tuple(),
+                                      correction_limit=70, max_sza=95, strength=3.0)
+
+    def test_default_settings(self, sunz_ds1, sunz_sza):
+        """Test default settings with sza data available."""
+        res = self.default((sunz_ds1, sunz_sza), test_attr='test')
         np.testing.assert_allclose(res.values,
                                    np.array([[0.00242814, 0.00235669], [0.00245885, 0.00238707]]),
                                    rtol=1e-5)
 
-    def test_basic_lims_provided(self, sunz_ds1, sunz_sza):
+    def test_custom_settings(self, sunz_ds1, sunz_sza):
         """Test custom settings with sza data available."""
-        from satpy.modifiers.geometry import SunZenithReducer
-        comp = SunZenithReducer(name='sza_reduction_test_custom', modifiers=tuple(),
-                                correction_limit=70, max_sza=95, strength=3.0)
-        res = comp((sunz_ds1, sunz_sza), test_attr='test')
+        res = self.custom((sunz_ds1, sunz_sza), test_attr='test')
         np.testing.assert_allclose(res.values,
                                    np.array([[0.01041319, 0.01030033], [0.01046164, 0.01034834]]),
                                    rtol=1e-5)