Add UniquePathNotUniqueException.

lib/neography/connection.rb

@@ -122,6 +122,7 @@ def handle_4xx_500_response(code, body)
         when /NoSuchPropertyException/       ; raise NoSuchPropertyException.new(message, code, stacktrace)
         when /RelationshipNotFoundException/ ; raise RelationshipNotFoundException.new(message, code, stacktrace)
         when /NotFoundException/             ; raise NotFoundException.new(message, code, stacktrace)
+        when /UniquePathNotUniqueException/  ; raise UniquePathNotUniqueException.new(message, code, stacktrace)
         else
           raise NeographyError.new(message, code, stacktrace)
         end

lib/neography/errors.rb

@@ -39,4 +39,7 @@ class SyntaxException < NeographyError; end
   # A path could not be found by node traversal
   class NotFoundException < NeographyError; end
 
+  # Thrown when CREATE UNIQUE matches multiple paths.
+  class UniquePathNotUniqueException < NeographyError; end
+
 end

spec/integration/rest_plugin_spec.rb

@@ -64,19 +64,35 @@
 
     it "can delete everything but start node" do
       @neo.execute_query("START n=node(*) MATCH n-[r?]-() WHERE ID(n) <> 0 DELETE n,r")
-      expect { 
+      expect {
         @neo.execute_query("start n=node({id}) return n", {:id => 1})
       }.to raise_error(Neography::BadInputException)
       root_node = @neo.execute_query("start n=node({id}) return n", {:id => 0})
       root_node.should_not be_nil
-    end 
+    end
 
     it "throws an error for an invalid query" do
       expect {
         @neo.execute_query("this is not a query")
       }.to raise_error(Neography::SyntaxException)
     end
 
+    it "throws an error for not unique paths in unique path creation" do
+      node1 = @neo.create_node
+      node2 = @neo.create_node
+
+      id1 = node1["self"].split('/').last.to_i
+      id2 = node2["self"].split('/').last.to_i
+
+      # create two 'FOO' relationships
+      @neo.execute_query("START a=node({id1}), b=node({id2}) CREATE a-[r:FOO]->b RETURN r", { :id1 => id1, :id2 => id2 })
+      @neo.execute_query("START a=node({id1}), b=node({id2}) CREATE a-[r:FOO]->b RETURN r", { :id1 => id1, :id2 => id2 })
+
+      expect {
+        @neo.execute_query("START a=node({id1}), b=node({id2}) CREATE UNIQUE a-[r:FOO]->b RETURN r", { :id1 => id1, :id2 => id2 })
+      }.to raise_error(Neography::UniquePathNotUniqueException)
+    end
+
   end
 
 end