fix specs for exception handling

- setup a class heirarchy of exceptions so i can easily rethrow
  any internal ohai error
- catch all the non-internal errors from running the plugin and
  just warn on those
- convert the argumenterror raises to ohai invalidplugin errors

lib/ohai/exception.rb

@@ -6,9 +6,9 @@
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
 # You may obtain a copy of the License at
-# 
+#
 #     http://www.apache.org/licenses/LICENSE-2.0
-# 
+#
 # Unless required by applicable law or agreed to in writing, software
 # distributed under the License is distributed on an "AS IS" BASIS,
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -19,12 +19,14 @@
 module Ohai
   module Exceptions
     class Exec < RuntimeError; end
-    class InvalidPluginName < Exception; end
-    class IllegalPluginDefinition < Exception; end
-    class AttributeNotFound < Exception; end
-    class ProviderNotFound < Exception; end
-    class DependencyCycle < Exception; end
-    class DependencyNotFound < Exception; end
-    class AttributeSyntaxError < Exception; end
+    class Error < Exception; end
+    class InvalidPlugin < Error; end
+    class InvalidPluginName < Error; end
+    class IllegalPluginDefinition < Error; end
+    class AttributeNotFound < Error; end
+    class ProviderNotFound < Error; end
+    class DependencyCycle < Error; end
+    class DependencyNotFound < Error; end
+    class AttributeSyntaxError < Error; end
   end
 end

lib/ohai/runner.rb

@@ -34,7 +34,7 @@ def initialize(controller, safe_run = false)
     # will be run even if they have been run before.
     def run_plugin(plugin, force = false)
       unless plugin.kind_of?(Ohai::DSL::Plugin)
-        raise ArgumentError, "Invalid plugin #{plugin} (must be an Ohai::DSL::Plugin or subclass)"
+        raise Ohai::Exceptions::InvalidPlugin, "Invalid plugin #{plugin} (must be an Ohai::DSL::Plugin or subclass)"
       end
 
       if Ohai::Config[:disabled_plugins].include?(plugin.name)
@@ -49,9 +49,9 @@ def run_plugin(plugin, force = false)
         when :version6
           run_v6_plugin(plugin, force)
         else
-          raise ArgumentError, "Invalid plugin version #{plugin.version} for plugin #{plugin}"
+          raise Ohai::Exceptions::InvalidPlugin, "Invalid plugin version #{plugin.version} for plugin #{plugin}"
         end
-      rescue Ohai::Exceptions::AttributeNotFound, Ohai::Exceptions::DependencyCycle
+      rescue Ohai::Exceptions::Error
         raise
       rescue Exception,Errno::ENOENT => e
         Ohai::Log.debug("Plugin #{plugin.name} threw exception #{e.inspect} #{e.backtrace.join("\n")}")

spec/unit/runner_spec.rb

@@ -29,7 +29,7 @@
 
   describe "when running an invalid plugin" do
     it "should raise error" do
-      lambda { @runner.run_plugin(double("Ohai::NotPlugin")) }.should raise_error(ArgumentError)
+      lambda { @runner.run_plugin(double("Ohai::NotPlugin")) }.should raise_error(Ohai::Exceptions::InvalidPlugin)
     end
   end
 
@@ -120,7 +120,7 @@
       let(:version) { :versionBla }
 
       it "should raise error" do
-        lambda { @runner.run_plugin(plugin) }.should raise_error(ArgumentError)
+        lambda { @runner.run_plugin(plugin) }.should raise_error(Ohai::Exceptions::InvalidPlugin)
       end
     end