Add gitlab ci configuration class that holds hash

lib/ci/gitlab_ci_yaml_processor.rb

@@ -12,18 +12,14 @@ module Ci
     attr_reader :before_script, :after_script, :image, :services, :path, :cache
 
     def initialize(config, path = nil)
-      @config = YAML.safe_load(config, [Symbol], [], true)
+      @config = Gitlab::Ci::Config.new(config).to_hash
       @path = path
 
-      unless @config.is_a? Hash
-        raise ValidationError, "YAML should be a hash"
-      end
-
-      @config = @config.deep_symbolize_keys
-
       initial_parsing
 
       validate!
+    rescue Gitlab::Ci::Config::ParserError => e
+      raise ValidationError, e.message
     end
 
     def builds_for_stage_and_ref(stage, ref, tag = false, trigger_request = nil)

lib/gitlab/ci/config.rb

+module Gitlab
+  module Ci
+    class Config
+      class ParserError < StandardError; end
+
+      def initialize(config)
+        @config = YAML.safe_load(config, [Symbol], [], true)
+
+        unless @config.is_a?(Hash)
+          raise ParserError, 'YAML should be a hash'
+        end
+
+        @config = @config.deep_symbolize_keys
+      end
+
+      def to_hash
+        @config
+      end
+    end
+  end
+end

spec/lib/gitlab/ci/config_spec.rb

+require 'spec_helper'
+
+describe Gitlab::Ci::Config do
+  let(:config) do
+    described_class.new(yml)
+  end
+
+  context 'when yml config is valid' do
+    let(:yml) do
+      <<-EOS
+        image: ruby:2.2
+
+        rspec:
+          script:
+            - gem install rspec
+            - rspec
+      EOS
+    end
+
+    describe '#to_hash' do
+      it 'returns hash created from string' do
+        hash = {
+          image: 'ruby:2.2',
+          rspec: {
+            script: ['gem install rspec',
+                     'rspec']
+          }
+        }
+
+        expect(config.to_hash).to eq hash
+      end
+    end
+  end
+end