Initial version of MigrationOptimizer and tests

django/db/migrations/operations/base.py

@@ -63,3 +63,16 @@ class Operation(object):
         Outputs a brief summary of what the action does.
         """
         return "%s: %s" % (self.__class__.__name__, self._constructor_args)
+
+    def __repr__(self):
+        return "<%s %s%s>" % (
+            self.__class__.__name__,
+            ", ".join(map(repr, self._constructor_args[0])),
+            ",".join(" %s=%r" % x for x in self._constructor_args[1].items()),
+        )
+
+    def __eq__(self, other):
+        return (self.__class__ == other.__class__) and (self.deconstruct() == other.deconstruct())
+
+    def __ne__(self, other):
+        return not (self == other)

django/db/migrations/operations/fields.py

@@ -29,6 +29,14 @@ class AddField(Operation):
     def describe(self):
         return "Add field %s to %s" % (self.name, self.model_name)
 
+    def __eq__(self, other):
+        return (
+            (self.__class__ == other.__class__) and
+            (self.name == other.name) and
+            (self.model_name == other.model_name) and
+            (self.field.deconstruct()[1:] == other.field.deconstruct()[1:])
+        )
+
 
 class RemoveField(Operation):
     """
@@ -92,6 +100,14 @@ class AlterField(Operation):
     def describe(self):
         return "Alter field %s on %s" % (self.name, self.model_name)
 
+    def __eq__(self, other):
+        return (
+            (self.__class__ == other.__class__) and
+            (self.name == other.name) and
+            (self.model_name == other.model_name) and
+            (self.field.deconstruct()[1:] == other.field.deconstruct()[1:])
+        )
+
 
 class RenameField(Operation):
     """

django/db/migrations/operations/models.py

@@ -32,6 +32,15 @@ class CreateModel(Operation):
     def describe(self):
         return "Create model %s" % (self.name, )
 
+    def __eq__(self, other):
+        return (
+            (self.__class__ == other.__class__) and
+            (self.name == other.name) and
+            (self.options == other.options) and
+            (self.bases == other.bases) and
+            ([(k, f.deconstruct()[1:]) for k, f in self.fields] == [(k, f.deconstruct()[1:]) for k, f in other.fields])
+        )
+
 
 class DeleteModel(Operation):
     """