Output: select fields you want for listings

Closes #24.

There is one gotcha. When user writes the option mistakenly like
`--fields`, Thor automatically parses it the same way as if user had
written `--fields=fields`, even though the `fields` option is configured
to type `string`, so it should not be treated like a switch imho. Seems
to me more like a bug than a feature, but I don't know how to write a
*clean* wrokaround, so I'd rather keep it this way for now.

features/usage.feature

@@ -50,6 +50,7 @@ Feature: Usage
       aeolus provider list
     
     Options:
+      [--fields=FIELDS]                # Fields (attributes) to print in the listing
       [--conductor-url=CONDUCTOR_URL]  
       [--username=USERNAME]            
       [--password=PASSWORD]            
@@ -85,6 +86,7 @@ Feature: Usage
       aeolus provider_account list
     
     Options:
+      [--fields=FIELDS]                # Fields (attributes) to print in the listing
       [--conductor-url=CONDUCTOR_URL]  
       [--username=USERNAME]            
       [--password=PASSWORD]            

lib/aeolus_cli/common_cli.rb

@@ -45,6 +45,17 @@ def banner(task, namespace = nil, subcommand = false)
       #     aeolus list
       #"#{basename} #{task.formatted_usage(self, $thor_runner, subcommand)}"
     end
+
+    def method_options_for_resource_list
+      method_option_fields
+      # TODO: method_option_sort_by
+    end
+
+    def method_option_fields
+      method_option :fields,
+        :type => :string,
+        :desc => 'Fields (attributes) to print in the listing'
+    end
   end
 
   def load_aeolus_config(options)
@@ -125,6 +136,15 @@ def set_output_format(options)
     @output_format = AeolusCli::Formatting.create_format(shell, options)
   end
 
+  # Transforms e.g. 'name,status' into [:name, :status]
+  def resource_fields(fields_option)
+    return nil unless fields_option
+    if fields_option == ''
+      raise Thor::MalformattedArgumentError.new("Option 'fields' cannot be empty.")
+    end
+    fields_option.split(',').map { |option| option.to_sym }
+  end
+
   def provider_type(type_s)
     # we need to hit the API to get the map of provider_type.name =>
     # provider_type.id, so make sure we only do this once.

lib/aeolus_cli/provider.rb

@@ -4,9 +4,10 @@
 class AeolusCli::Provider < AeolusCli::CommonCli
 
   desc "list", "List all providers"
+  method_options_for_resource_list
   def list
     providers = AeolusCli::Model::Provider.all
-    output_format.list(providers)
+    output_format.list(providers, resource_fields(options[:fields]))
   end
 
   desc "add PROVIDER_NAME", "Add a provider"

lib/aeolus_cli/provider_account.rb

@@ -4,10 +4,11 @@
 class AeolusCli::ProviderAccount < AeolusCli::CommonCli
 
   desc "list", "list provider accounts"
+  method_options_for_resource_list
   # TODO maybe an optional variable for provider_type
   def list
     accounts = AeolusCli::Model::ProviderAccount.all_full_detail
-    output_format.list(accounts)
+    output_format.list(accounts, resource_fields(options[:fields]))
   end
 
   desc "add PROVIDER_ACCOUNT_LABEL", "Add a provider account"

spec/aeolus_cli/common_cli_spec.rb

@@ -0,0 +1,24 @@
+require 'aeolus_cli/common_cli'
+
+describe AeolusCli::CommonCli do
+  let(:common_cli) { AeolusCli::CommonCli.new() }
+
+  context "#resource_fields" do
+    context "non-empty fields" do
+      subject { common_cli.send(:resource_fields, "name,status,is_cool") }
+      it { should == [:name, :status, :is_cool] }
+    end
+
+    context "empty fields" do
+      subject { common_cli.send(:resource_fields, "") }
+      it do
+        expect { subject }.to raise_error Thor::MalformattedArgumentError
+      end
+    end
+
+    context "nil fields" do
+      subject { common_cli.send(:resource_fields, nil) }
+      it { should == nil }
+    end
+  end
+end

spec/aeolus_cli/formatting_spec.rb

@@ -0,0 +1,23 @@
+require 'aeolus_cli/formatting'
+
+describe AeolusCli::Formatting do
+  let(:formatting) { AeolusCli::Formatting }
+  let(:shell) { double('shell') }
+
+  context ".create_format" do
+    subject { formatting.create_format(shell, { :format => 'human' }) }
+    let(:human_format) { double('human format') }
+    let(:human_format_class) do
+      double('human format class').tap do |clazz|
+        clazz.stub(:new).with(shell).and_return(human_format)
+      end
+    end
+
+    before do
+      formatting.should_receive(:require).with("aeolus_cli/formatting/human_format").and_return(true)
+      formatting.should_receive(:const_get).with("HumanFormat").and_return(human_format_class)
+    end
+
+    it { should == human_format }
+  end
+end