2 files changed, 48 insertions, 12 deletions
diff --git a/lib/dslkeywords/resource.rb b/lib/dslkeywords/resource.rb
index 6612428..884dec9 100644
--- a/lib/dslkeywords/resource.rb
+++ b/lib/dslkeywords/resource.rb
@@ -1,31 +1,47 @@
+require 'set'
+
 require_relative 'keyword'
 
 module RCM
   # To track recource dependencies
-  module Dependency
-    # Only to have the resourcename[id] syntax available in the DSL
-    class SyntaxSugar
-      def initialize(name)
-        @name = name
+  module ResourceDependencies
+    def initialize(...)
+      super(...)
+      @valid_resources = Set.new
+      ObjectSpace.each_object(Class).each do |klass|
+        @valid_resources << klass.to_s.sub('RCM::', '').downcase.to_sym if klass < Resource
       end
+    end
 
+    # Only to have the resourcename[id] syntax available in the DSL
+    class SyntaxSugar
+      def initialize(name) = @name = name
       def [](other) = "#{@name}['#{other}']"
     end
 
-    def method_missing(method_name) = SyntaxSugar.new(method_name)
+    class NoSuchResource < StandardError; end
+
+    def method_missing(method_name)
+      raise NoSuchResource, "No such resource: #{method_name}" unless @valid_resources.include?(method_name)
+
+      SyntaxSugar.new(method_name)
+    end
+
     def respond_to_missing? = true
 
     def depends_on(*others)
-      @depends_on = {} if @depends_on.nil?
+      @dependencies = {} if @dependencies.nil?
       others.each do |other|
         info "Registered dependency on #{other}"
-        @depends_on[other] = {}
+        @dependencies[other] = {}
       end
     end
+
+    def dependencies = @dependencies.nil ? [] : @dependencies
   end
 
   # A resource is something concrete to be managed, e.g. a file, or a CRON job.
   class Resource < Keyword
-    include Dependency
+    include ResourceDependencies
   end
 end
diff --git a/test/lib/dslkeywords/dependency_test.rb b/test/lib/dslkeywords/dependency_test.rb
index ccbaec6..3e23282 100644
--- a/test/lib/dslkeywords/dependency_test.rb
+++ b/test/lib/dslkeywords/dependency_test.rb
@@ -4,14 +4,34 @@ require 'fileutils'
 require_relative '../../../lib/dsl'
 
 class RCMDependencyTest < Minitest::Test
-  def test_dependency
+  def test_depends_on
     configure_from_scratch do
       notify 'foo' do
-        depends_on notify['bar'], file['baz']
-        :HELLO
+        depends_on notify['bar'], notify['baz']
+        :foo_message
       end
 
       notify 'bar'
+
+      notify 'baz' do
+        depends_on notify['bar']
+        :baz_message
+      end
+    end
+  end
+
+  def test_depends_on_invalid_resource
+    correct_exception_thrown = false
+
+    configure_from_scratch do
+      notify 'foo' do
+        depends_on invalid['baz']
+        :foo_message
+      end
+    rescue RCM::ResourceDependencies::NoSuchResource
+      correct_exception_thrown = true
     end
+
+    assert correct_exception_thrown
   end
 end