try fix broken tests due to ambiguous process ordering

xsimlab/tests/conftest.py

@@ -86,11 +86,13 @@ def other_derived_quantity(self):
 
 class SomeProcess(Process):
     some_param = Variable((), description='some parameter')
-    copy_param = Variable((), provided=True)
     x = ForeignVariable(Grid, 'x')
     quantity = ForeignVariable(Quantity, 'quantity')
     some_effect = Variable('x', group='effect', provided=True)
 
+    # SomeProcess always appears before OtherProcess in a model
+    copy_param = Variable((), provided=True)
+
     def initialize(self):
         self.copy_param.value = self.some_param.value
 
@@ -103,10 +105,12 @@ def finalize(self):
 
 class OtherProcess(Process):
     x = ForeignVariable(Grid, 'x')
-    copy_param = ForeignVariable(SomeProcess, 'copy_param')
     quantity = ForeignVariable(Quantity, 'quantity')
     other_effect = Variable('x', group='effect', provided=True)
 
+    # OtherProcess should always appear after SomeProcess in a model
+    copy_param = ForeignVariable(SomeProcess, 'copy_param')
+
     def run_step(self, dt):
         self.other_effect.value = self.x.value * self.copy_param.value - dt
 
@@ -118,6 +122,7 @@ def x2(self):
 class PlugProcess(Process):
     meta_param = Variable(())
     some_param = ForeignVariable(SomeProcess, 'some_param', provided=True)
+    x = ForeignVariable(Grid, 'x')
 
     def run_step(self, *args):
         self.some_param.value = self.meta_param.value

xsimlab/tests/test_model.py

@@ -88,8 +88,6 @@ def test_update_processes(self, model):
                           'other_process': OtherProcess,
                           'quantity': Quantity})
         actual = model.update_processes({'plug_process': PlugProcess})
-
-        # TODO: more advanced (public?) test function to compare two models?
         assert list(actual) == list(expected)
 
     def test_drop_processes(self, model):