Make all IPA error classes inherit from RESTError

Currently several IPA error classes inherit from Exception. This
patch makes the base class of those classes RESTError. These
error classes are also restructured to initialize in the same
manner as other classes which inherit from RESTError. Additionally
test cases are added for these error classes.

Change-Id: Ie6235e4cc25f072b789b2e72e4592d4cf02bfedc
Closes-bug: #1410372

ironic_python_agent/errors.py

@@ -228,30 +228,34 @@ class VirtualMediaBootError(RESTError):
         super(VirtualMediaBootError, self).__init__(details)
 
 
-class ExtensionError(Exception):
+class ExtensionError(RESTError):
     pass
 
 
-class UnknownNodeError(Exception):
+class UnknownNodeError(RESTError):
     """Error raised when the agent is not associated with an Ironic node."""
 
     message = 'Agent is not associated with an Ironic node.'
 
-    def __init__(self, message=None):
-        if message is not None:
-            self.message = message
-        super(UnknownNodeError, self).__init__(self.message)
+    def __init__(self, details=None):
+        if details is not None:
+            details = details
+        else:
+            details = self.message
+        super(UnknownNodeError, self).__init__(details)
 
 
-class HardwareManagerNotFound(Exception):
+class HardwareManagerNotFound(RESTError):
     """Error raised when no valid HardwareManager can be found."""
 
     message = 'No valid HardwareManager found.'
 
-    def __init__(self, message=None):
-        if message is not None:
-            self.message = message
-        super(HardwareManagerNotFound, self).__init__(self.message)
+    def __init__(self, details=None):
+        if details is not None:
+            details = details
+        else:
+            details = self.message
+        super(HardwareManagerNotFound, self).__init__(details)
 
 
 class HardwareManagerMethodNotFound(RESTError):

ironic_python_agent/tests/errors.py

@@ -108,6 +108,10 @@ class TestErrors(test_base.BaseTestCase):
                  (errors.BlockDeviceEraseError(DETAILS), SAME_DETAILS),
                  (errors.BlockDeviceError(DETAILS), SAME_DETAILS),
                  (errors.VirtualMediaBootError(DETAILS), SAME_DETAILS),
+                 (errors.UnknownNodeError(), SAME_CL_MSG),
+                 (errors.UnknownNodeError(DETAILS), SAME_DETAILS),
+                 (errors.HardwareManagerNotFound(), SAME_CL_MSG),
+                 (errors.HardwareManagerNotFound(DETAILS), SAME_DETAILS),
                  (errors.HardwareManagerMethodNotFound('method'),
                   DIFF_CL_DETAILS),
                  (errors.IncompatibleHardwareMethodError(), SAME_CL_MSG),