Create files when calling update_file

yorm/__init__.py

@@ -3,7 +3,7 @@
 import sys
 
 __project__ = 'YORM'
-__version__ = '0.5.a1'
+__version__ = '0.5.a2'
 
 VERSION = __project__ + '-' + __version__
 

yorm/exceptions.py

@@ -35,6 +35,6 @@ class ConversionError(Error, ValueError):
     """Value could not be converted to the specified type."""
 
 
-class UseageError(Error):
+class MappingError(Error):
 
     """The API was called incorrectly."""

yorm/test/test_utilities.py

@@ -88,7 +88,7 @@ def test_with_attrs(self):
     def test_multiple(self):
         """Verify mapping cannot be enabled twice."""
         sample = utilities.sync(self.Sample(), "sample.yml")
-        with pytest.raises(exceptions.UseageError):
+        with pytest.raises(exceptions.MappingError):
             utilities.sync(sample, "sample.yml")
 
     @patch('os.path.isfile', Mock(return_value=True))
@@ -333,7 +333,7 @@ def test_update_wrong_base(self):
         """Verify an exception is raised with the wrong base."""
         instance = Mock()
 
-        with pytest.raises(exceptions.UseageError):
+        with pytest.raises(exceptions.MappingError):
             utilities.update(instance)
 
 
@@ -355,7 +355,7 @@ def test_update_wrong_base(self):
         """Verify an exception is raised with the wrong base."""
         instance = Mock()
 
-        with pytest.raises(exceptions.UseageError):
+        with pytest.raises(exceptions.MappingError):
             utilities.update_object(instance)
 
 
@@ -370,14 +370,15 @@ def test_update(self):
 
         utilities.update_file(instance)
 
-        assert not instance.yorm_mapper.fetch.called
-        assert instance.yorm_mapper.store.called
+        assert False is instance.yorm_mapper.fetch.called
+        assert False is instance.yorm_mapper.create.called
+        assert True is instance.yorm_mapper.store.called
 
     def test_update_wrong_base(self):
         """Verify an exception is raised with the wrong base."""
         instance = Mock()
 
-        with pytest.raises(exceptions.UseageError):
+        with pytest.raises(exceptions.MappingError):
             utilities.update_file(instance)
 
     def test_store_not_called_with_auto_off(self):
@@ -388,8 +389,20 @@ def test_store_not_called_with_auto_off(self):
         utilities.update_file(instance, force=False)
 
         assert False is instance.yorm_mapper.fetch.called
+        assert False is instance.yorm_mapper.create.called
         assert False is instance.yorm_mapper.store.called
 
+    def test_create_called_if_the_file_is_missing(self):
+        instance = MockMappable()
+        instance.yorm_mapper.reset_mock()
+        instance.yorm_mapper.exists = False
+
+        utilities.update_file(instance)
+
+        assert False is instance.yorm_mapper.fetch.called
+        assert True is instance.yorm_mapper.create.called
+        assert True is instance.yorm_mapper.store.called
+
 
 if __name__ == '__main__':
     pytest.main()

yorm/utilities.py

@@ -47,24 +47,18 @@ class Mapped(Mappable, instance.__class__):
 
         """Original class with `Mappable` as the base."""
 
-    mapper = set_mapper(instance, path, attrs, auto=auto)
+    instance.__class__ = Mapped
 
-    if existing is True:
-        if not mapper.exists:
-            raise exceptions.FileMissingError
-    elif existing is False:
-        if mapper.exists:
-            raise exceptions.FileAlreadyExistsError
+    mapper = set_mapper(instance, path, attrs, auto=auto)
+    _check_existance(mapper, existing)
 
     if mapper.auto:
         if not mapper.exists:
             mapper.create()
             mapper.store()
         mapper.fetch()
 
-    instance.__class__ = Mapped
     log.info("mapped %r to '%s'", instance, path)
-
     return instance
 
 
@@ -148,40 +142,61 @@ def update(instance, fetch=True, force=True, store=True):
         update_object(instance, force=force)
 
 
-def update_object(instance, force=True):
+def update_object(instance, existing=True, force=True):
     """Synchronize changes into a mapped object from its file.
 
     :param instance: object with patched YAML mapping behavior
+    :param existing: indicate if file is expected to exist or not
     :param force: update the object even if the file appears unchanged
 
     """
     log.info("manually updating %r from file...", instance)
     _check_base(instance, mappable=True)
 
     mapper = get_mapper(instance)
+    _check_existance(mapper, existing)
+
     if mapper.modified or force:
         mapper.fetch()
 
 
-def update_file(instance, force=True):
+def update_file(instance, existing=None, force=True):
     """Synchronize changes into a mapped object's file.
 
     :param instance: object with patched YAML mapping behavior
+    :param existing: indicate if file is expected to exist or not
     :param force: update the file even if automatic sync is off
 
     """
     log.info("manually saving %r to file...", instance)
     _check_base(instance, mappable=True)
 
     mapper = get_mapper(instance)
-    print(mapper.auto)
+    _check_existance(mapper, existing)
+
     if mapper.auto or force:
+        if not mapper.exists:
+            mapper.create()
         mapper.store()
 
 
 def _check_base(obj, mappable=True):
     """Confirm an object's base class is `Mappable` as required."""
     if mappable and not isinstance(obj, Mappable):
-        raise exceptions.UseageError("{} is not mapped".format(repr(obj)))
+        raise exceptions.MappingError("{} is not mapped".format(repr(obj)))
     if not mappable and isinstance(obj, Mappable):
-        raise exceptions.UseageError("{} is already mapped".format(repr(obj)))
+        raise exceptions.MappingError("{} is already mapped".format(repr(obj)))
+
+
+def _check_existance(mapper, existing=None):
+    """Confirm the expected state of the file.
+
+    :param existing: indicate if file is expected to exist or not
+
+    """
+    if existing is True:
+        if not mapper.exists:
+            raise exceptions.FileMissingError
+    elif existing is False:
+        if mapper.exists:
+            raise exceptions.FileAlreadyExistsError