add basic why-run/assertion structure to group provider

chef/lib/chef/provider/group.rb

@@ -52,6 +52,14 @@ def load_current_resource
 
         @current_resource
       end
+
+      def define_resource_requirements
+        requirements.assert(:modify) do |a| 
+          a.assertion { @group_exists } 
+          a.failure_message(Chef::Exceptions::Group, "Cannot modify #{@new_resource} - group does not exist!")
+          a.whyrun("Group #{@new_resource} does not exist. Unless it would have been created earlier in this run, this attempt to modify it would fail.")
+        end
+      end
 
       # Check to see if a group needs any changes
       #
@@ -76,43 +84,45 @@ def compare_group
       def action_create
         case @group_exists
         when false
-          create_group
-          Chef::Log.info("#{@new_resource} created")
-          @new_resource.updated_by_last_action(true)
+          converge_by("would create #{@new_resource}") do 
+            create_group
+            Chef::Log.info("#{@new_resource} created")
+          end
         else 
           if compare_group
-            manage_group
-            Chef::Log.info("#{@new_resource} altered")
-            @new_resource.updated_by_last_action(true)
+            converge_by("would alter group #{@new_resource}") do 
+              manage_group
+              Chef::Log.info("#{@new_resource} altered")
+            end
           end
         end
       end
 
       def action_remove
         if @group_exists
-          remove_group
-          @new_resource.updated_by_last_action(true)
-          Chef::Log.info("#{@new_resource} removed")
+          converge_by("would remove group #{@new_resource}") do
+            remove_group
+            Chef::Log.info("#{@new_resource} removed")
+          end
+
         end
       end
 
       def action_manage
         if @group_exists && compare_group
-          manage_group 
-          @new_resource.updated_by_last_action(true)
-          Chef::Log.info("#{@new_resource} managed")
+          converge_by("would manage group #{@new_resource}") do
+            manage_group 
+            Chef::Log.info("#{@new_resource} managed")
+          end
         end
       end
 
       def action_modify
-        if @group_exists 
-          if compare_group
+        if compare_group
+          converge_by("would modify group #{@new_resource}") do
             manage_group
-            @new_resource.updated_by_last_action(true)
             Chef::Log.info("#{@new_resource} modified")
           end
-        else
-          raise Chef::Exceptions::Group, "Cannot modify #{@new_resource} - group does not exist!"
         end
       end
 

chef/spec/unit/provider/group_spec.rb

@@ -114,35 +114,35 @@
     it "should call create_group if the group does not exist" do
       @provider.group_exists = false
       @provider.should_receive(:create_group).and_return(true)
-      @provider.action_create
+      @provider.run_action(:create)
     end
 
     it "should set the the new_resources updated flag when it creates the group" do
       @provider.group_exists = false
       @provider.stub!(:create_group)
-      @provider.action_create
+      @provider.run_action(:create)
       @provider.new_resource.should be_updated
     end
 
     it "should check to see if the group has mismatched attributes if the group exists" do
       @provider.group_exists = true
       @provider.stub!(:compare_group).and_return(false)
-      @provider.action_create
+      @provider.run_action(:create)
       @provider.new_resource.should_not be_updated
     end
 
     it "should call manage_group if the group exists and has mismatched attributes" do
       @provider.group_exists = true
       @provider.stub!(:compare_group).and_return(true)
       @provider.should_receive(:manage_group).and_return(true)
-      @provider.action_create
+      @provider.run_action(:create)
     end
 
     it "should set the the new_resources updated flag when it creates the group if we call manage_group" do
       @provider.group_exists = true
       @provider.stub!(:compare_group).and_return(true)
       @provider.stub!(:manage_group).and_return(true)
-      @provider.action_create
+      @provider.run_action(:create)
       @new_resource.should be_updated
     end
   end
@@ -152,14 +152,14 @@
     it "should not call remove_group if the group does not exist" do
       @provider.group_exists = false
       @provider.should_not_receive(:remove_group) 
-      @provider.action_remove
+      @provider.run_action(:remove)
       @provider.new_resource.should_not be_updated
     end
 
     it "should call remove_group if the group exists" do
       @provider.group_exists = true
       @provider.should_receive(:remove_group)
-      @provider.action_remove
+      @provider.run_action(:remove)
       @provider.new_resource.should be_updated
     end
   end
@@ -173,26 +173,26 @@
     it "should run manage_group if the group exists and has mismatched attributes" do
       @provider.should_receive(:compare_group).and_return(true)
       @provider.should_receive(:manage_group).and_return(true)
-      @provider.action_manage
+      @provider.run_action(:manage)
     end
 
     it "should set the new resources updated flag to true if manage_group is called" do
       @provider.stub!(:compare_group).and_return(true)
       @provider.stub!(:manage_group).and_return(true)
-      @provider.action_manage
+      @provider.run_action(:manage)
       @new_resource.should be_updated
     end
 
     it "should not run manage_group if the group does not exist" do
       @provider.group_exists = false
       @provider.should_not_receive(:manage_group)
-      @provider.action_manage
+      @provider.run_action(:manage)
     end
 
     it "should not run manage_group if the group exists but has no differing attributes" do
       @provider.should_receive(:compare_group).and_return(false)
       @provider.should_not_receive(:manage_group)
-      @provider.action_manage
+      @provider.run_action(:manage)
     end
   end
 
@@ -205,25 +205,25 @@
     it "should run manage_group if the group exists and has mismatched attributes" do
       @provider.should_receive(:compare_group).and_return(true)
       @provider.should_receive(:manage_group).and_return(true)
-      @provider.action_modify
+      @provider.run_action(:modify)
     end
 
     it "should set the new resources updated flag to true if manage_group is called" do
       @provider.stub!(:compare_group).and_return(true)
       @provider.stub!(:manage_group).and_return(true)
-      @provider.action_modify
+      @provider.run_action(:modify)
       @new_resource.should be_updated
     end
 
     it "should not run manage_group if the group exists but has no differing attributes" do
       @provider.should_receive(:compare_group).and_return(false)
       @provider.should_not_receive(:manage_group)
-      @provider.action_modify
+      @provider.run_action(:modify)
     end
 
     it "should raise a Chef::Exceptions::Group if the group doesn't exist" do
       @provider.group_exists = false
-      lambda { @provider.action_modify }.should raise_error(Chef::Exceptions::Group)
+      lambda { @provider.run_action(:modify) }.should raise_error(Chef::Exceptions::Group)
     end
   end
 end