We now check for powershell/dsc compat in provider.jdmundrawala/issue-2027-master

The problem with raising an exception when the resource is created
was that it was not possible to have a chef recipe that installs
the correct version of powershell and then runs the dsc_script
resource.
See https://github.com/opscode/chef/issues/2027

4 files changed, 167 insertions, 153 deletions

diff --git a/lib/chef/provider/dsc_script.rb b/lib/chef/provider/dsc_script.rb
index 5d7322842c..9bb2b5f364 100644
--- a/lib/chef/provider/dsc_script.rb
+++ b/lib/chef/provider/dsc_script.rb
@@ -46,9 +46,11 @@ class Chef
       end
 
       def load_current_resource
-        @dsc_resources_info = run_configuration(:test)
-        @resource_converged = @dsc_resources_info.all? do |resource|
-          !resource.changes_state?
+        if supports_dsc?
+          @dsc_resources_info = run_configuration(:test)
+          @resource_converged = @dsc_resources_info.all? do |resource|
+            !resource.changes_state?
+          end
         end
       end
 
@@ -56,8 +58,26 @@ class Chef
         true
       end
 
+      def define_resource_requirements
+        requirements.assert(:run) do |a|
+          err = [
+            'Could not find Dsc on the system',
+            powershell_info_str,
+            "Powershell 4.0 or higher was not detected on your system and is required to use the dsc_script resource.",
+          ]
+          a.assertion { supports_dsc? }
+          a.failure_message Chef::Exceptions::NoProviderAvailable, err.join(' ')
+          a.whyrun err + ["Assuming a previous resource installs Powershell 4.0 or higher."]
+          a.block_action!
+        end
+      end
+
       protected
 
+      def supports_dsc?
+        run_context && Chef::Platform.supports_dsc?(node)
+      end
+
       def run_configuration(operation)
         config_directory = ::Dir.mktmpdir("chef-dsc-script")
         configuration_data_path = get_configuration_data_path(config_directory)
@@ -143,6 +163,14 @@ class Chef
             end
           end
       end
+
+      def powershell_info_str
+        if run_context && run_context.node[:languages] && run_context.node[:languages][:powershell]
+          install_info = "Powershell #{run_context.node[:languages][:powershell][:version]} was found on the system."
+        else
+          install_info = 'Powershell was not found.'
+        end
+      end
     end
   end
 end
diff --git a/lib/chef/resource/dsc_script.rb b/lib/chef/resource/dsc_script.rb
index 2972ace1aa..76ac6659d6 100644
--- a/lib/chef/resource/dsc_script.rb
+++ b/lib/chef/resource/dsc_script.rb
@@ -28,12 +28,8 @@ class Chef
         super
         @allowed_actions.push(:run)
         @action = :run
-        if(run_context && Chef::Platform.supports_dsc?(run_context.node))
-          @provider = Chef::Provider::DscScript
-        else
-          raise Chef::Exceptions::NoProviderAvailable,
-            "#{powershell_info_str(run_context)}\nPowershell 4.0 or higher was not detected on your system and is required to use the dsc_script resource."
-        end
+        @provider = Chef::Provider::DscScript
+        @resource_name = :dsc_script
       end
 
       def code(arg=nil)
@@ -125,16 +121,6 @@ class Chef
           :kind_of => [ Integer ]
         )
       end
-
-      private
-
-      def powershell_info_str(run_context)
-        if run_context && run_context.node[:languages] && run_context.node[:languages][:powershell]
-            install_info = "Powershell #{run_context.node[:languages][:powershell][:version]} was found on the system."
-          else
-            install_info = 'Powershell was not found.'
-          end
-      end
     end
   end
 end
diff --git a/spec/unit/provider/dsc_script_spec.rb b/spec/unit/provider/dsc_script_spec.rb
index 8a7a7b5c6a..d8fbee3ff9 100644
--- a/spec/unit/provider/dsc_script_spec.rb
+++ b/spec/unit/provider/dsc_script_spec.rb
@@ -22,123 +22,152 @@ require 'chef/util/dsc/resource_info'
 require 'spec_helper'
 
 describe Chef::Provider::DscScript do
-  let (:node) {
-    node = Chef::Node.new
-    node.automatic[:languages][:powershell][:version] = '4.0'
-    node
-  }
-  let (:events) { Chef::EventDispatch::Dispatcher.new }
-  let (:run_context) { Chef::RunContext.new(node, {}, events) }
-  let (:resource) { Chef::Resource::DscScript.new("script", run_context) }
-  let (:provider) do
-    Chef::Provider::DscScript.new(resource, run_context)
-  end
-
-  describe '#load_current_resource' do
-    it "describes the resource as converged if there were 0 DSC resources" do
-      allow(provider).to receive(:run_configuration).with(:test).and_return([])
-      provider.load_current_resource
-      provider.instance_variable_get('@resource_converged').should be_true
+  context 'when DSC is available' do
+    let (:node) {
+      node = Chef::Node.new
+      node.automatic[:languages][:powershell][:version] = '4.0'
+      node
+    }
+    let (:events) { Chef::EventDispatch::Dispatcher.new }
+    let (:run_context) { Chef::RunContext.new(node, {}, events) }
+    let (:resource) { Chef::Resource::DscScript.new("script", run_context) }
+    let (:provider) do
+      Chef::Provider::DscScript.new(resource, run_context)
     end
 
-    it "describes the resource as not converged if there is 1 DSC resources that is converged" do
-      dsc_resource_info = Chef::Util::DSC::ResourceInfo.new('resource', false, ['nothing will change something'])
-      allow(provider).to receive(:run_configuration).with(:test).and_return([dsc_resource_info])
-      provider.load_current_resource
-      provider.instance_variable_get('@resource_converged').should be_true
+    describe '#load_current_resource' do
+      it "describes the resource as converged if there were 0 DSC resources" do
+        allow(provider).to receive(:run_configuration).with(:test).and_return([])
+        provider.load_current_resource
+        provider.instance_variable_get('@resource_converged').should be_true
+      end
+
+      it "describes the resource as not converged if there is 1 DSC resources that is converged" do
+        dsc_resource_info = Chef::Util::DSC::ResourceInfo.new('resource', false, ['nothing will change something'])
+        allow(provider).to receive(:run_configuration).with(:test).and_return([dsc_resource_info])
+        provider.load_current_resource
+        provider.instance_variable_get('@resource_converged').should be_true
+      end
+
+      it "describes the resource as not converged if there is 1 DSC resources that is not converged" do
+        dsc_resource_info = Chef::Util::DSC::ResourceInfo.new('resource', true, ['will change something'])
+        allow(provider).to receive(:run_configuration).with(:test).and_return([dsc_resource_info])
+        provider.load_current_resource
+        provider.instance_variable_get('@resource_converged').should be_false
+      end
+
+      it "describes the resource as not converged if there are any DSC resources that are not converged" do
+        dsc_resource_info1 = Chef::Util::DSC::ResourceInfo.new('resource', true, ['will change something'])
+        dsc_resource_info2 = Chef::Util::DSC::ResourceInfo.new('resource', false, ['nothing will change something'])
+
+        allow(provider).to receive(:run_configuration).with(:test).and_return([dsc_resource_info1, dsc_resource_info2])
+        provider.load_current_resource
+        provider.instance_variable_get('@resource_converged').should be_false
+      end
+
+      it "describes the resource as converged if all DSC resources that are converged" do
+        dsc_resource_info1 = Chef::Util::DSC::ResourceInfo.new('resource', false, ['nothing will change something'])
+        dsc_resource_info2 = Chef::Util::DSC::ResourceInfo.new('resource', false, ['nothing will change something'])
+
+        allow(provider).to receive(:run_configuration).with(:test).and_return([dsc_resource_info1, dsc_resource_info2])
+        provider.load_current_resource
+        provider.instance_variable_get('@resource_converged').should be_true
+      end
     end
 
-    it "describes the resource as not converged if there is 1 DSC resources that is not converged" do
-      dsc_resource_info = Chef::Util::DSC::ResourceInfo.new('resource', true, ['will change something'])
-      allow(provider).to receive(:run_configuration).with(:test).and_return([dsc_resource_info])
-      provider.load_current_resource
-      provider.instance_variable_get('@resource_converged').should be_false
+    describe '#generate_configuration_document' do
+      # I think integration tests should cover these cases
+
+      it 'uses configuration_document_from_script_path when a dsc script file is given' do
+        allow(provider).to receive(:load_current_resource)
+        resource.command("path_to_script")
+        generator = double('Chef::Util::DSC::ConfigurationGenerator')
+        generator.should_receive(:configuration_document_from_script_path)
+        allow(Chef::Util::DSC::ConfigurationGenerator).to receive(:new).and_return(generator)
+        provider.send(:generate_configuration_document, 'tmp', nil)
+      end
+
+      it 'uses configuration_document_from_script_code when a the dsc resource is given' do
+        allow(provider).to receive(:load_current_resource)
+        resource.code("ImADSCResource{}")
+        generator = double('Chef::Util::DSC::ConfigurationGenerator')
+        generator.should_receive(:configuration_document_from_script_code)
+        allow(Chef::Util::DSC::ConfigurationGenerator).to receive(:new).and_return(generator)
+        provider.send(:generate_configuration_document, 'tmp', nil)
+      end
+
+      it 'should noop if neither code or command are provided' do
+        allow(provider).to receive(:load_current_resource)
+        generator = double('Chef::Util::DSC::ConfigurationGenerator')
+        generator.should_receive(:configuration_document_from_script_code).with('', anything(), anything())
+        allow(Chef::Util::DSC::ConfigurationGenerator).to receive(:new).and_return(generator)
+        provider.send(:generate_configuration_document, 'tmp', nil)
+      end
     end
 
-    it "describes the resource as not converged if there are any DSC resources that are not converged" do
-      dsc_resource_info1 = Chef::Util::DSC::ResourceInfo.new('resource', true, ['will change something'])
-      dsc_resource_info2 = Chef::Util::DSC::ResourceInfo.new('resource', false, ['nothing will change something'])
-
-      allow(provider).to receive(:run_configuration).with(:test).and_return([dsc_resource_info1, dsc_resource_info2])
-      provider.load_current_resource
-      provider.instance_variable_get('@resource_converged').should be_false
+    describe 'action_run' do
+      it 'should converge the script if it is not converged' do
+        dsc_resource_info = Chef::Util::DSC::ResourceInfo.new('resource', true, ['will change something'])
+        allow(provider).to receive(:run_configuration).with(:test).and_return([dsc_resource_info])
+        allow(provider).to receive(:run_configuration).with(:set)
+
+        provider.run_action(:run)
+        resource.should be_updated
+      end
+
+      it 'should not converge if the script is already converged' do
+        allow(provider).to receive(:run_configuration).with(:test).and_return([])
+        
+        provider.run_action(:run)
+        resource.should_not be_updated
+      end
     end
 
-    it "describes the resource as converged if all DSC resources that are converged" do
-      dsc_resource_info1 = Chef::Util::DSC::ResourceInfo.new('resource', false, ['nothing will change something'])
-      dsc_resource_info2 = Chef::Util::DSC::ResourceInfo.new('resource', false, ['nothing will change something'])
-
-      allow(provider).to receive(:run_configuration).with(:test).and_return([dsc_resource_info1, dsc_resource_info2])
-      provider.load_current_resource
-      provider.instance_variable_get('@resource_converged').should be_true
+    describe '#generate_description' do
+      it 'removes the resource name from the beginning of any log line from the LCM' do
+        dsc_resource_info = Chef::Util::DSC::ResourceInfo.new('resourcename', true, ['resourcename doing something', 'lastline'])
+        provider.instance_variable_set('@dsc_resources_info', [dsc_resource_info])
+        provider.send(:generate_description)[1].should match(/converge DSC resource resourcename by doing something/)
+      end
+
+      it 'ignores the last line' do
+        dsc_resource_info = Chef::Util::DSC::ResourceInfo.new('resourcename', true, ['resourcename doing something', 'lastline'])
+        provider.instance_variable_set('@dsc_resources_info', [dsc_resource_info])
+        provider.send(:generate_description)[1].should_not match(/lastline/)
+      end
+
+      it 'reports a dsc resource has not been changed if the LCM reported no change was required' do
+        dsc_resource_info = Chef::Util::DSC::ResourceInfo.new('resourcename', false, ['resourcename does nothing', 'lastline'])
+        provider.instance_variable_set('@dsc_resources_info', [dsc_resource_info])
+        provider.send(:generate_description)[1].should match(/converge DSC resource resourcename by doing nothing/)
+      end
     end
   end
 
-  describe '#generate_configuration_document' do
-    # I think integration tests should cover these cases
-
-    it 'uses configuration_document_from_script_path when a dsc script file is given' do
-      allow(provider).to receive(:load_current_resource)
-      resource.command("path_to_script")
-      generator = double('Chef::Util::DSC::ConfigurationGenerator')
-      generator.should_receive(:configuration_document_from_script_path)
-      allow(Chef::Util::DSC::ConfigurationGenerator).to receive(:new).and_return(generator)
-      provider.send(:generate_configuration_document, 'tmp', nil)
-    end
-
-    it 'uses configuration_document_from_script_code when a the dsc resource is given' do
-      allow(provider).to receive(:load_current_resource)
-      resource.code("ImADSCResource{}")
-      generator = double('Chef::Util::DSC::ConfigurationGenerator')
-      generator.should_receive(:configuration_document_from_script_code)
-      allow(Chef::Util::DSC::ConfigurationGenerator).to receive(:new).and_return(generator)
-      provider.send(:generate_configuration_document, 'tmp', nil)
-    end
-
-    it 'should noop if neither code or command are provided' do
-      allow(provider).to receive(:load_current_resource)
-      generator = double('Chef::Util::DSC::ConfigurationGenerator')
-      generator.should_receive(:configuration_document_from_script_code).with('', anything(), anything())
-      allow(Chef::Util::DSC::ConfigurationGenerator).to receive(:new).and_return(generator)
-      provider.send(:generate_configuration_document, 'tmp', nil)
-    end
-  end
-
-  describe 'action_run' do
-    it 'should converge the script if it is not converged' do
-      dsc_resource_info = Chef::Util::DSC::ResourceInfo.new('resource', true, ['will change something'])
-      allow(provider).to receive(:run_configuration).with(:test).and_return([dsc_resource_info])
-      allow(provider).to receive(:run_configuration).with(:set)
-
-      provider.run_action(:run)
-      resource.should be_updated
-    end
-
-    it 'should not converge if the script is already converged' do
-      allow(provider).to receive(:run_configuration).with(:test).and_return([])
-      
-      provider.run_action(:run)
-      resource.should_not be_updated
-    end
-  end
-
-  describe '#generate_description' do
-    it 'removes the resource name from the beginning of any log line from the LCM' do
-      dsc_resource_info = Chef::Util::DSC::ResourceInfo.new('resourcename', true, ['resourcename doing something', 'lastline'])
-      provider.instance_variable_set('@dsc_resources_info', [dsc_resource_info])
-      provider.send(:generate_description)[1].should match(/converge DSC resource resourcename by doing something/)
-    end
-
-    it 'ignores the last line' do
-      dsc_resource_info = Chef::Util::DSC::ResourceInfo.new('resourcename', true, ['resourcename doing something', 'lastline'])
-      provider.instance_variable_set('@dsc_resources_info', [dsc_resource_info])
-      provider.send(:generate_description)[1].should_not match(/lastline/)
-    end
+  context 'when Dsc is not available' do
+    let (:node) { Chef::Node.new }
+    let (:events) { Chef::EventDispatch::Dispatcher.new }
+    let (:run_context) { Chef::RunContext.new(node, {}, events) }
+    let (:resource) { Chef::Resource::DscScript.new('script', run_context) }
+    let (:provider) { Chef::Provider::DscScript.new(resource, run_context) }
+
+    describe 'action_run' do
+      ['1.0', '2.0', '3.0'].each do |version|
+        it "raises an exception for powershell version '#{version}'" do
+          node.automatic[:languages][:powershell][:version] = version
+
+          expect {
+            provider.run_action(:run)
+          }.to raise_error(Chef::Exceptions::NoProviderAvailable)
+        end
+      end
+
+      it 'raises an exception if Powershell is not present' do
+        expect {
+          provider.run_action(:run)
+        }.to raise_error(Chef::Exceptions::NoProviderAvailable)
+      end
 
-    it 'reports a dsc resource has not been changed if the LCM reported no change was required' do
-      dsc_resource_info = Chef::Util::DSC::ResourceInfo.new('resourcename', false, ['resourcename does nothing', 'lastline'])
-      provider.instance_variable_set('@dsc_resources_info', [dsc_resource_info])
-      provider.send(:generate_description)[1].should match(/converge DSC resource resourcename by doing nothing/)
     end
   end
 end
diff --git a/spec/unit/resource/dsc_script_spec.rb b/spec/unit/resource/dsc_script_spec.rb
index cbd502a61c..eb9d19e553 100644
--- a/spec/unit/resource/dsc_script_spec.rb
+++ b/spec/unit/resource/dsc_script_spec.rb
@@ -95,33 +95,4 @@ describe Chef::Resource::DscScript do
       expect { dsc_test_resource.configuration_data_script(configuration_data_script) }.to raise_error(ArgumentError)
     end
   end
-
-  context 'when Powershell does not supported Dsc' do
-    ['1.0', '2.0', '3.0'].each do |version|
-      it "raises an exception for powershell version '#{version}'" do
-        node = Chef::Node.new
-        node.automatic[:languages][:powershell][:version] = version
-        empty_events = Chef::EventDispatch::Dispatcher.new
-        dsc_test_run_context = Chef::RunContext.new(node, {}, empty_events)
-
-        expect {
-          Chef::Resource::DscScript.new(dsc_test_resource_name, dsc_test_run_context)
-        }.to raise_error(Chef::Exceptions::NoProviderAvailable)
-      end
-    end
-  end
-
-  context 'when Powershell is not present' do
-    let (:dsc_test_run_context) {
-      node = Chef::Node.new
-      empty_events = Chef::EventDispatch::Dispatcher.new
-      dsc_test_run_context = Chef::RunContext.new(node, {}, empty_events)
-    }
-
-    it 'raises an exception if powershell is not present' do
-        expect {
-          Chef::Resource::DscScript.new(dsc_test_resource_name, dsc_test_run_context)
-        }.to raise_error(Chef::Exceptions::NoProviderAvailable)
-      end
-  end
 end