add sanity check when importing data from a dictionary

Signed-off-by: Jose Borreguero <[email protected]>

reduction/lr_reduction/reduction_template_reader.py

@@ -66,6 +66,19 @@ def __init__(self):
         self.incident_medium_index_selected = 0
 
     def from_dict(self, data_dict):
+        r"""Update object's attributes with a dictionary with entries of the type  attribute_name: attribute_value.
+
+        Raises
+        ------
+        ValueError
+            if one entry of the dictionary is not an attribute of this object
+        """
+
+        # check all keys are data_dict are attributes of object `self`
+        attribute_names = list(vars(self))
+        if not all(key in attribute_names for key in data_dict):
+            raise ValueError("data_dir contains invalid entries")
+        # update attribute values
         for k, v in data_dict.items():
             setattr(self, k, v)
 

reduction/test/test_reduction_template_reader.py

@@ -0,0 +1,29 @@
+# third-party imports
+import pytest
+
+# lr_reduction imports
+from lr_reduction.reduction_template_reader import ReductionParameters
+
+
+class TestReductionParameters:
+
+    def test_two_backgrounds(self):
+        r"""verify the xml dump writes what we want"""
+        redparms = ReductionParameters()
+        redparms.two_backgrounds = True
+        assert "<two_backgrounds_flag>True</two_backgrounds_flag>" in redparms.to_xml()
+
+    def test_from_dict(self):
+        r"""verify method from_dict raises when passed some nonsense"""
+
+        redparms = ReductionParameters()
+        # valid data dictionary
+        redparms.from_dict(dict(two_backgrounds=True))
+        assert redparms.two_backgrounds
+        # invalid data dictionary
+        with pytest.raises(ValueError) as excinfo:
+            redparms.from_dict(dict(nonsense=True))
+        assert "data_dir contains invalid entries" == str(excinfo.value)
+
+if __name__ == "__main__":
+    pytest.main(__file__)