Added a prototype for the model cache version calculation.

cache_version/__init__.py

@@ -0,0 +1,3 @@
+class ModelCacheVersionCalculator(object):
+    def get_version(model):
+        pass

cache_version/models.py

@@ -0,0 +1,19 @@
+import hashlib
+from inspect_model import InspectModel
+
+def get_model_cache_version(model):
+    inspected_model = InspectModel(model)
+
+    fields_and_types = {}
+
+    for field in inspected_model.fields:
+        fields_and_types[field] = getattr(model, field)
+
+    for field in inspected_model.relation_fields:
+        fields_and_types[field] = getattr(model, field)
+
+
+    for field in inspected_model.many_fields:
+        fields_and_types[field] = getattr(model, field)
+
+    return hashlib.sha1(str(fields_and_types)).hexdigest()

requirements/common.txt

@@ -1,2 +1,3 @@
 Django>=1.4
+django-inspect-model>=0.7.0
 django-compat>=1.0.2

requirements/testing.txt

@@ -1,2 +1,4 @@
 pytest>=2.7.0
 pytest-django>=2.8.0
+pytest-describe>=0.10.0
+pytest-mock>=0.4.1

tests/unit/test_get_model_cache_version.py

@@ -0,0 +1,27 @@
+import pytest
+import mock
+
+from cache_version.models import get_model_cache_version
+
+def describe_get_model_cache_version():
+    @pytest.fixture
+    def model():
+        return mock.sentinel.MODEL
+
+    @pytest.fixture
+    def mocked_inspect_model(mocker):
+        return mocker.patch('cache_version.models.InspectModel')
+
+    @pytest.fixture
+    def mocked_hashlib(mocker):
+        return mocker.patch('cache_version.models.hashlib')
+
+    def it_should_inspect_the_target_model(model, mocked_inspect_model):
+        get_model_cache_version(model)
+
+        mocked_inspect_model.assert_called_once_with(model)
+
+    def it_should_return_a_hash_of_all_field_names_and_field_types(model, mocked_inspect_model, mocked_hashlib):
+        get_model_cache_version(model)
+
+        mocked_hashlib.sha1(mock.ANY).hexdigest.assert_called_once_with()