Adapt test_smallest_difference() to changes in tools.py

Author: SabineHaas

tests/test_tools.py

@@ -1,21 +1,29 @@
 from windpowerlib.tools import smallest_difference
+import pandas as pd
 
 
 class TestTools:
 
     def test_smallest_difference(self):
-        # value_1 closer to comparative value
-        expected_output = (30, 5.0)
-        assert smallest_difference(30, 10, 100, 5.0, 6.0) == expected_output
-        # value_1 = comparative value
-        expected_output = (100, 5.0)
-        assert smallest_difference(100, 10, 100, 5.0, 6.0) == expected_output
-        # value_2 closer to comparative value
-        expected_output = (30, 6.0)
-        assert smallest_difference(10, 30, 100, 5.0, 6.0) == expected_output
-        # value_2 = comparative value
-        expected_output = (100, 6.0)
-        assert smallest_difference(10, 100, 100, 5.0, 6.0) == expected_output
-        # value_2 is None
-        expected_output = (10, 5.0)
-        assert smallest_difference(10, None, 100, 5.0, 6.0) == expected_output
+        parameters = {'data_frame': pd.DataFrame(data={'v_wind':
+                                                       [4.0, 5.0, 6.0]},
+                                                 index=[100, 150, 200]),
+                      'comp_value': 100,
+                      'column_name': 'v_wind'}
+        # TODO: test v_wind as pd.Series and np.array
+
+        # comparative value is an index of data frame
+        expected_output = (100, 4.0)
+        assert smallest_difference(**parameters) == expected_output
+        # comparative value between indices of data frame
+        expected_output = (150, 5.0)
+        parameters['comp_value'] = 175
+        assert smallest_difference(**parameters) == expected_output
+        # comparative value > indices of data frame
+        expected_output = (200, 6.0)
+        parameters['comp_value'] = 250
+        assert smallest_difference(**parameters) == expected_output
+        # comparative value < indices of data frame
+        expected_output = (100, 4.0)
+        parameters['comp_value'] = 90
+        assert smallest_difference(**parameters) == expected_output