versionary: add get_applicable method

CONTRIBUTORS.md

@@ -11,3 +11,5 @@ Keep the list in alfabetical order please.
 
  * Devhouse Spindle {[email protected]}
  * Marco Vellinga {[email protected]}
+ * Konrad Weihmann {[email protected]}
+

tests/test_decorator.py

@@ -1,7 +1,7 @@
 from pytest import raises
 
 from versionary.decorators import versioned
-from versionary.exceptions import DuplicateVersionException, InheritanceException, InvalidVersionException
+from versionary.exceptions import DuplicateVersionException, InheritanceException, InvalidVersionException, NoApplicableVersion
 
 from .utils.mixed_members import MixedClass, mixed_func
 from .utils.versioned_members import MyClass, MyInheritanceClass, my_function, your_function
@@ -24,6 +24,27 @@ def test_decorator_for_classes_without_number():
     assert MyClass.v2().hello() == 4
 
 
+def test_decorator_for_classes_get_applicable_max():
+    """
+    Test the decorator for latest classes via get_applicable.
+    """
+    assert MyClass.get_applicable()().hello() == 4
+    assert MyClass.get_applicable(minver=2)().hello() == 4
+    assert MyClass.get_applicable(maxver=1)().hello() == 3
+    with raises(NoApplicableVersion):
+        MyClass.get_applicable(minver=100)().hello()
+
+def test_decorator_for_classes_get_applicable_min():
+    """
+    Test the decorator for earliest classes via get_applicable.
+    """
+    assert MyClass.get_applicable(func=min)().hello() == 3
+    assert MyClass.get_applicable(minver=2, func=min)().hello() == 4
+    assert MyClass.get_applicable(maxver=1, func=min)().hello() == 3
+    with raises(NoApplicableVersion):
+        MyClass.get_applicable(minver=100, func=min)().hello()
+
+
 def test_decorator_for_class_inheritance_without_number():
     """
     Test the decorator for classes that inherit without a number.

tests/test_utils.py

@@ -29,7 +29,7 @@ def test_create_proxy_class():
     """
     base_name = 'base_name'
 
-    proxy = create_proxy_class(base_name)
+    proxy = create_proxy_class(base_name, 123)
 
     message = 'Cannot call `base_name` directly, use versioned attributes instead (`base_name`.vX)'
 

versionary/decorators.py

@@ -116,7 +116,7 @@ def wrap(member):
             validate_inheritance_for_class(member)
 
         # Get or create the proxy class to return.
-        proxy = version_members.get('proxy', create_proxy_class(name))
+        proxy = version_members.get('proxy', create_proxy_class(name, module))
 
         # Add new version method to this proxy class.
         setattr(proxy, '%s%s' % (PROXY_VERSION_TAG, version), staticmethod(member))

versionary/exceptions.py

@@ -41,3 +41,10 @@ class NotCallableException(Exception):
     Raised when trying to call the ProxyClass which shouldn't be called.
     """
     pass
+
+
+class NoApplicableVersion(Exception):
+    """
+    Raised when no version matching the criteria was found.
+    """
+    pass

versionary/utils.py

@@ -4,7 +4,7 @@
 
 from six import with_metaclass
 
-from .exceptions import InvalidVersionException, NotCallableException
+from .exceptions import InvalidVersionException, NotCallableException, NoApplicableVersion
 
 CLASS, FUNCTION = 0, 1
 CLASS_VERSION_TAG = 'V'
@@ -37,7 +37,7 @@ def determine_member_type(member):
     return member_type
 
 
-def create_proxy_class(base_name):
+def create_proxy_class(base_name, mod):
     """
     Function to create a proxy class to be able to set attributes to.
     This is used to make my_func.v1() or MyClass.v1() possible.
@@ -83,7 +83,17 @@ def __getattr__(cls, name):
             raise AttributeError('%r has no attribute %r' %
                                  (cls._base_name, name))
 
+        def get_applicable(cls, minver=0, maxver=10e9, func=max):
+            version_table = getattr(cls._modref, '__version_table__')
+            try:
+                best_version = func([x for x in version_table[cls._base_name]
+                                   ['members'].keys() if x <= maxver and x >= minver])
+                return version_table[cls._base_name]['members'][best_version]
+            except ValueError:
+                raise NoApplicableVersion()
+
     setattr(ProxyType, '_base_name', base_name)
+    setattr(ProxyType, '_modref', mod)
 
     class ProxyClass(with_metaclass(ProxyType)):
         """