Merge pull request #130 from paulocheque/teach-flex

Accept override an Lesson

django_dynamic_fixture/ddf.py

@@ -65,10 +65,6 @@ class PendingField(Exception):
     "Internal exception to control pending fields when using Copier."
 
 
-class CantOverrideLesson(Exception):
-    "Override a lesson is an anti-pattern and will turn your test suite very hard to understand."
-
-
 def _validate_model(model_class):
     if not is_model_class(model_class):
         raise InvalidReceiverError(model_class, 'Invalid model')
@@ -249,10 +245,15 @@ def get_instance(cls):
         return cls.instance
 
     def add_configuration(self, model_class, kwargs, name=None):
+        import os
+        import warnings
         if name in [None, True]:
             name = self.DEFAULT_KEY
         if model_class in self.configs and name in self.configs[model_class]:
-            raise CantOverrideLesson('A lesson {} has already been saved for the model {}'.format(name, model_class))
+            if not os.getenv('DDF_SHELL_MODE'):
+                msg = "Override a lesson is an anti-pattern and will turn your test suite very hard to understand."
+                msg = 'A lesson {} has already been saved for the model {}. {}'.format(name, model_class, msg)
+                warnings.warn(msg, RuntimeWarning)
         model_class_config = self.configs.setdefault(model_class, {})
         model_class_config[name] = kwargs
 
@@ -676,9 +677,6 @@ def get(self, model_class, ddf_lesson=None, **kwargs):
         return instance
 
     def teach(self, model_class, ddf_lesson=None, **kwargs):
-        '''
-        @raise an CantOverrideLesson error if the same model/lesson were called twice.
-        '''
         library = DDFLibrary.get_instance()
         for field_name in kwargs.keys():
             if field_name in self._DDF_CONFIGS:

django_dynamic_fixture/tests/test_ddf_teaching_and_lessons.py

@@ -22,10 +22,13 @@ def test_teach_a_default_lesson_for_a_model(self):
         instance = self.ddf.get(ModelForLibrary)
         assert instance.integer == 1000
 
-    def test_default_lesson_must_NOT_be_overrided(self):
+    def test_default_lesson_may_be_overrided_although_it_is_an_anti_pattern(self):
         self.ddf.teach(ModelForLibrary, integer=1000)
-        with pytest.raises(CantOverrideLesson):
-            self.ddf.teach(ModelForLibrary, integer=1001)
+        instance = self.ddf.get(ModelForLibrary)
+        assert instance.integer == 1000
+        self.ddf.teach(ModelForLibrary, integer=1001)
+        instance = self.ddf.get(ModelForLibrary)
+        assert instance.integer == 1001
 
     def test_it_must_NOT_raise_an_error_if_user_try_to_use_a_not_saved_default_configuration(self):
         self.ddf.get(ModelForLibrary)

docs/source/ddf.rst

@@ -223,4 +223,4 @@ You can have **many custom lessons** too, giving names to them::
     instance = G(Model, ddf_lesson='my custom lesson 2')
     assert instance.field_x == 99
 
-ps: Just be aware that lessons can not be overriden, since this is an anti-pattern and may let your test suite very hard to understand.
+ps: Just be aware that overriding lessons is an anti-pattern and may let your test suite very hard to understand.

docs/source/more.rst

@@ -75,7 +75,6 @@ List of Exceptions
 * *InvalidCopierExpressionError*: The specified expression used in a Copier is invalid.
 * *InvalidModelError*: Invalid Model: The class is not a model or it is abstract.
 * *InvalidDDFSetupError*: ddf_setup.py has execution errors
-* *CantOverrideLesson*: Override a lesson is an anti-pattern and will turn your test suite very hard to understand.
 
 
 Decorators (New in 1.4.0)

docs/source/settings.rst

@@ -51,3 +51,6 @@ You can configure DDF in ``settings.py`` file. You can also override the global
     # You can override the global config for one case:
     G(Model, debug_mode=True)
     G(Model, debug_mode=False)
+
+
+* **DDF_SHELL_MODE** (Default = False): To disable some DDF warnings so DDF can be used better in Python shell: to populate the DB, for exampel.