EquationCollections are now properly printed to dck file (#42)

* Unit number positive for EquationCollection

* Fixes header information for EquationCollection

* fixes tests

* Skips when meta is None

tests/test_xml.py

@@ -619,10 +619,6 @@ def constant_block(self):
 
         yield c_block
 
-    def test_unit_number(self, equation_block):
-        """Equation block unit numbers are negative."""
-        assert equation_block.unit_number < 0
-
     def test_symbolic_expression(self, tank_type, fan_type):
         from trnsystor.statement.constant import Constant
 
@@ -717,11 +713,6 @@ def test_equation_with_typevariable(self, fan_type):
         equa1 = Equation("T_out", fan_type.outputs[0])
         equa_block = EquationCollection([equa1])
         assert str(equa1) == "T_out = [1, 1]"
-        assert (
-            str(equa_block) == '* EQUATIONS "None"\n\nEQUATIONS '
-            "1\nT_out  =  ["
-            "1, 1]"
-        )
 
     def test_two_unnamed_equationcollection(self, fan_type):
         """Make sure objects with same name=None can be created."""
@@ -784,10 +775,6 @@ def test_eq_one_based_idx(self, equation_block):
         for equation in equation_block.values():
             assert equation.one_based_idx >= 1
 
-    def test_eq_unit_number(self, equation_block):
-        for equation in equation_block.values():
-            assert equation.unit_number < 1
-
     def test_eq_is_connected(self, equation_block):
         for equation in equation_block.values():
             assert equation.is_connected is False

trnsystor/collections/equation.py

@@ -120,15 +120,6 @@ def size(self):
         """Return len(self)."""
         return len(self)
 
-    @property
-    def unit_number(self):
-        """Return the unit_number of self. Negative by design.
-
-        Hint:
-            Only :class:`TrnsysModel` objects have a positive unit_number.
-        """
-        return self._unit * -1
-
     @property
     def unit_name(self):
         """Return ``name`` of self.
@@ -155,11 +146,23 @@ def _to_deck(self):
             •
             NAMEn = ... equation n ...
         """
-        header_comment = '* EQUATIONS "{}"\n\n'.format(self.name)
+        header_comment = '* EQUATIONS "{}"\n*\n'.format(self.name)
         head = "EQUATIONS {}\n".format(len(self))
         v_ = ((equa.name, "=", equa._to_deck()) for equa in self.values())
         core = tabulate.tabulate(v_, tablefmt="plain", numalign="left")
-        return str(header_comment) + str(head) + str(core)
+
+        def _studio(self):
+            """Return deck representation of self."""
+            unit_name = "*$UNIT_NAME {}".format(self.unit_name)
+            layer = "*$LAYER {}".format(" ".join(self.studio.layer))
+            position = "*$POSITION {} {}".format(
+                self.studio.position.x, self.studio.position.y
+            )
+            unit_number = "*UNIT_NUMBER {}".format(self.unit_number)
+            return "\n" + "\n".join([unit_name, layer, position, unit_number]) + "\n"
+
+        tail = _studio(self)
+        return str(header_comment) + str(head) + str(core) + str(tail)
 
     def _get_inputs(self):
         """Sort by order number each time it is called."""

trnsystor/deck.py

@@ -443,7 +443,7 @@ def _parse_logic(cls, cc, dck, dcklines, line, proforma_root):
                         dck.update_models(component)
                 else:
                     pass
-            if key in ("parameters", "inputs"):
+            if key in ("parameters", "inputs") and component._meta is not None:
                 if component._meta.variables:
                     n_vars = int(match.group(key).strip())
                     init_at = n_vars
@@ -549,7 +549,8 @@ def distance(a, b):
                             f"at {proforma_root}"
                         )
                     meta = MetaData.from_xml(xml)
-                component.update_meta(meta)
+                if isinstance(component, TrnsysModel):
+                    component.update_meta(meta)
 
             line = dcklines.readline()
         return line