409 imputation validation

mbs_results/validate_imputation.py

@@ -0,0 +1,25 @@
+import pandas as pd
+
+
+def validate_imputation(df: pd.DataFrame, target: str) -> None:
+    """
+    Validation for the imputation, including:
+    - no missing values in target column
+
+    Parameters
+    ----------
+    df : pd.DataFrame
+        data with imputed values
+    target : str
+        name of column containing target variable
+
+    Raises
+    ------
+    """
+    if df[target].isna().any():
+        raise ValueError(
+            f"""
+            Target column should have no missing values following imputation:
+            missing values found in column {target}
+            """
+        )

tests/data/validate_imputation/target_missing_values.csv

@@ -0,0 +1,4 @@
+no_missing,one_missing,all_missing
+11,14,,
+12,15,,
+13,,

tests/helper_functions.py

@@ -1,3 +1,4 @@
+from contextlib import contextmanager
 from pathlib import Path
 
 import pandas as pd
@@ -22,3 +23,10 @@ def load_filter(filter_path):
             df["date"] = pd.to_datetime(df["date"], format="%Y%m")
 
         return df
+
+
+# when updating to python>=3.7 this can be replaced by importing
+# contextlib.nullcontext as does_not_raise
+@contextmanager
+def does_not_raise():
+    yield

tests/test_validate_imputation.py

@@ -0,0 +1,36 @@
+from pathlib import Path
+
+import pandas as pd
+import pytest
+from helper_functions import does_not_raise
+
+from mbs_results.validate_imputation import validate_imputation
+
+
+@pytest.fixture(scope="class")
+def filepath():
+    return Path("tests/data/validate_imputation")
+
+
+@pytest.fixture(scope="class")
+def missing_target_values_data(filepath):
+    return pd.read_csv(filepath / "target_missing_values.csv", index_col=False)
+
+
+class TestValidateImputation:
+    @pytest.mark.parametrize(
+        "target_column_name,expectation",
+        [
+            ("no_missing", does_not_raise()),
+            ("one_missing", pytest.raises(ValueError)),
+            ("all_missing", pytest.raises(ValueError)),
+        ],
+    )
+    def test_target_missing_values_validation(
+        self,
+        missing_target_values_data,
+        target_column_name,
+        expectation,
+    ):
+        with expectation:
+            validate_imputation(missing_target_values_data, target_column_name)