Merge pull request #43 from oemof/fix/encourage-constant-labels

Require label of Node to be given

src/oemof/network/network/edge.py

@@ -102,7 +102,7 @@ def input(self):
     @input.setter
     def input(self, i):
         old_input = self.input
-        self.label = Edge.Label(i, self.label.output)
+        self._label = Edge.Label(i, self.label.output)
         if old_input is None and i is not None and self.output is not None:
             i.outputs[self.output] = self
 
@@ -113,6 +113,6 @@ def output(self):
     @output.setter
     def output(self, o):
         old_output = self.output
-        self.label = Edge.Label(self.label.input, o)
+        self._label = Edge.Label(self.label.input, o)
         if old_output is None and o is not None and self.input is not None:
             o.inputs[self.input] = self

src/oemof/network/network/entity.py

@@ -44,7 +44,7 @@ class Entity:
         to easily attach custom information to any Entity.
     """
 
-    def __init__(self, label=None, *, custom_properties=None):
+    def __init__(self, label, *, custom_properties=None):
         self._label = label
         if custom_properties is None:
             custom_properties = {}
@@ -78,13 +78,9 @@ def label(self):
         """
         try:
             return self._label if self._label is not None else self._id_label
-        except AttributeError:
+        except AttributeError:  # Workaround for problems with pickle/dill
             return hash(self._id_label)
 
     @property
     def _id_label(self):
         return "<{} #0x{:x}>".format(type(self).__name__, id(self))
-
-    @label.setter
-    def label(self, label):
-        self._label = label

src/oemof/network/network/nodes.py

@@ -44,7 +44,7 @@ class Node(Entity):
 
     def __init__(
         self,
-        label=None,
+        label,
         *,
         inputs=None,
         outputs=None,

tests/test_network_classes.py

@@ -60,7 +60,7 @@ def test_symmetric_input_output_assignment(self):
         )
 
     def test_accessing_outputs_of_a_node_without_output_flows(self):
-        n = Node()
+        n = Node(label="node")
         exception = None
         outputs = None
         try:
@@ -79,7 +79,7 @@ def test_accessing_outputs_of_a_node_without_output_flows(self):
         )
 
     def test_accessing_inputs_of_a_node_without_input_flows(self):
-        n = Node()
+        n = Node(label="node")
         exception = None
         inputs = None
         try:
@@ -98,7 +98,7 @@ def test_accessing_inputs_of_a_node_without_input_flows(self):
         )
 
     def test_that_the_outputs_attribute_of_a_node_is_a_mapping(self):
-        n = Node()
+        n = Node(label="node")
         exception = None
         try:
             n.outputs.values()
@@ -252,16 +252,16 @@ def test_entity_input_output_type_assertions(self):
         with pytest.raises(ValueError):
             Node("An entity with an input", inputs={"Not a Node": "A Flow"})
 
-    def test_node_label_without_private_attribute(self):
+    def test_node_requires_label(self):
         """
-        A `Node` without `label` doesn't have the `_label` attribute set.
+        A `Node` without `label` cannot be constructed.
         """
-        n = Node()
-        assert not n._label
+        with pytest.raises(TypeError):
+            _ = Node()
 
     def test_node_label_if_its_not_explicitly_specified(self):
         """If not explicitly given, a `Node`'s label is based on its `id`."""
-        n = Node()
+        n = Node(label=None)
         assert "0x{:x}>".format(id(n)) in n.label
 
 
@@ -344,25 +344,26 @@ def test_entity_registration(self):
 
 def test_deprecated_classes():
     with pytest.warns(FutureWarning):
-        Bus()
+        Bus("bus")
     with pytest.warns(FutureWarning):
-        Sink()
+        Sink("sink")
     with pytest.warns(FutureWarning):
-        Source()
+        Source("source")
     with pytest.warns(FutureWarning):
-        Transformer()
+        Transformer("transformer")
 
 
 def test_custom_properties():
-    node0 = Node()
+    node0 = Node("n0")
 
     assert not node0.custom_properties
 
     node1 = Node(
+        "n1",
         custom_properties={
             "foo": "bar",
             1: 2,
-        }
+        },
     )
     assert node1.custom_properties["foo"] == "bar"
     assert node1.custom_properties[1] == 2