Merge "Add API to enable calling module to register an exception"

2 files changed, 32 insertions, 1 deletions

diff --git a/oslo/vmware/exceptions.py b/oslo/vmware/exceptions.py
index 133fbed..a8b92c3 100644
--- a/oslo/vmware/exceptions.py
+++ b/oslo/vmware/exceptions.py
@@ -222,10 +222,20 @@ _fault_classes_registry = {
 
 
 def get_fault_class(name):
-    """Get a named subclass of NovaException."""
+    """Get a named subclass of VMwareDriverException."""
     name = str(name)
     fault_class = _fault_classes_registry.get(name)
     if not fault_class:
         LOG.debug('Fault %s not matched.', name)
         fault_class = VMwareDriverException
     return fault_class
+
+
+def register_fault_class(name, exception):
+    fault_class = _fault_classes_registry.get(name)
+    if not issubclass(exception, VMwareDriverException):
+        raise TypeError(_("exception should be a subclass of "
+                          "VMwareDriverException"))
+    if fault_class:
+        LOG.debug('Overriding exception for %s', name)
+    _fault_classes_registry[name] = exception
diff --git a/tests/test_api.py b/tests/test_api.py
index 6c02051..cd24fa5 100644
--- a/tests/test_api.py
+++ b/tests/test_api.py
@@ -487,3 +487,24 @@ class VMwareAPISessionTest(base.TestCase):
 
         for k, v in _unknown_exceptions.iteritems():
             self._poll_task_well_known_exceptions(k, v)
+
+    def _create_subclass_exception(self):
+        class VimSubClass(exceptions.VMwareDriverException):
+            pass
+        return VimSubClass
+
+    def test_register_fault_class(self):
+        exc = self._create_subclass_exception()
+        exceptions.register_fault_class('ValueError', exc)
+        self.assertEqual(exc, exceptions.get_fault_class('ValueError'))
+
+    def test_register_fault_class_override(self):
+        exc = self._create_subclass_exception()
+        exceptions.register_fault_class(exceptions.ALREADY_EXISTS, exc)
+        self.assertEqual(exc,
+                         exceptions.get_fault_class(exceptions.ALREADY_EXISTS))
+
+    def test_register_fault_classi_invalid(self):
+        self.assertRaises(TypeError,
+                          exceptions.register_fault_class,
+                          'ValueError', ValueError)