Throw exception if trying to find relationships with illegal arguments …

…closes #189

Example:  a_person.friends("a string")  will now raise an exception

Gemfile

@@ -1,7 +1,7 @@
 source :gemcutter
 
 
-# gem "neo4j-wrapper", :path => "/home/andreas/projects/neo4j-wrapper"
+#gem "neo4j-wrapper", :path => "/home/andreas/projects/neo4j-wrapper"
 
 gemspec
 

lib/neo4j/rails/has_n.rb

@@ -151,6 +151,7 @@ def define_has_n_methods_for(rel_type, options) #:nodoc:
                 def #{rel_type}(cypher_hash_query = nil, &cypher_block)
                     dsl = _decl_rels_for(:'#{rel_type}')
                     if cypher_hash_query || cypher_block
+                      raise "Expected a hash, can't translated to cypher where statements" if cypher_hash_query && !cypher_hash_query.is_a?(Hash)
                       Neo4j::Wrapper::HasN::Nodes.new(self, dsl, cypher_hash_query, &cypher_block)
                     else
                       storage = _create_or_get_storage_for_decl_rels(dsl)

lib/neo4j/rails/relationships/node_dsl.rb

@@ -142,6 +142,7 @@ def find(*args, &block)
         #
         def all(*args)
           unless args.empty?
+            raise "Illegal argument, expected a node" unless args.first.kind_of?(Neo4j::NodeMixin)
             enum = Enumerator.new(@storage, :each_node, @dir).find { |n| n == args.first }
           else
             enum = Enumerator.new(@storage, :each_node, @dir)

spec/integration/active_record_style_relationships_spec.rb

@@ -131,6 +131,13 @@ class ModelRelationship1 < Neo4j::Rails::Relationship
         @actor.acted_in.find(@movie_1).should_not be_nil
       end
 
+      it "can not find anything else except nodes" do
+        lambda{@actor.acted_in.find("bla")}.should raise_error
+        lambda{@actor.acted_in.first("bla")}.should raise_error
+        lambda{@actor.acted_in.all("bla")}.should raise_error
+        lambda{@actor.acted_in.all(:bla => 42)}.should raise_error
+      end
+
       it "find a child node by id" do
         @actor.acted_in.find(@movie_1.id).should_not be_nil
       end

spec/integration/finders_spec.rb

@@ -8,7 +8,7 @@
       property :name, :index => :exact
       property :age, :type => Fixnum, :index => :exact
       validates_presence_of :name
-
+      has_n(:items)
       def to_s
         name
       end
@@ -79,6 +79,11 @@ def non_findable_model_allocated_ids
         findable_class.find(-99).should be_nil
       end
 
+      it "should raise an exception when trying to find related nodes with a string" do
+        lambda{findable_class.new.items("bla")}.should raise_error
+        lambda{findable_class.new.items.all("bla")}.should raise_error
+      end
+
       it "should return nil when passed " do
         findable_class.find(-99).should be_nil
       end