use np.isclose to compare variables in unittests

(sometimes there are insignificant changes in float variables)

Author: mhidas

test_aodntools/base_test.py

@@ -68,7 +68,7 @@ def compare_variables(self, dataset, skip_vars=('source_file', 'instrument_id'))
                     differences.append((var, "shapes differ"))
 
                 # compare the raw data arrays (not the masked_array)
-                if not all(dataset[var][:].data == expected[var][:].data):
+                if not all(np.isclose(dataset[var][:].data, expected[var][:].data)):
                     differences.append((var, "variable values differ"))
 
         self.assertEqual([], differences)