add assertion that there are no missing values in any column

Author: drbenvincent

causalpy/tests/test_data_loading.py

@@ -10,3 +10,5 @@
 def test_data_loading(dataset_name):
     df = cp.load_data(dataset_name)
     assert isinstance(df, pd.DataFrame)
+    # Check that there are no missing values in any column
+    assert df.isnull().sum().sum() == 0