def test_evaluation_process_single(self):
"""
Calling process() with one MinusOne should return a new df that
subtract one from every input value, but not affect the input dataframe.
"""
pipeline = [MinusOne()]
df = pd.DataFrame([{"a": 1, "b": 2}, {"a": 3, "b": 4}])
result = Evaluation(df).process(pipeline).get_df()
expected = pd.DataFrame([{"a": 0, "b": 1}, {"a": 2, "b": 3}])
# check if input eval has been altered
self.assertFalse(result.equals(df))
self.assertFalse(df.equals(expected))
# check if output eval has correct values
self.assertTrue(result.equals(expected))
def test_evaluation_process_empty(self):
"""
Calling process() with an empty list of processors should return the
input DF without any changes.
"""
df = pd.DataFrame([{"a": 1, "b": 2}, {"a": 3, "b": 4}])
result = Evaluation(df).process([]).get_df()
self.assertTrue(result.equals(df))
def test_evaluation_get_df_equality(self):
"""
get_df() should return a dataframe with values equal to constructor
argument
"""
df = pd.DataFrame([{"a": 1, "b": 2}, {"a": 3, "b": 4}])
result = Evaluation(df).get_df()
self.assertIsInstance(result, pd.DataFrame)
self.assertTrue(result.equals(df))
def test_evaluation_get_df_defensive_copy(self):
"""
get_df() should return a copy of the constructor argument to prevent
caller from mutating the dataframe
"""
df = pd.DataFrame([{"a": 1, "b": 2}, {"a": 3, "b": 4}])
result = Evaluation(df).get_df()
result["a"][0] = 5 # mutate result
self.assertFalse(result.equals(df))
