Add specs for openrouter provider

Author: khasinski

lib/ruby_llm/providers/openrouter/streaming.rb

@@ -13,6 +13,8 @@ def stream_url
 
         def handle_stream(&block) # rubocop:disable Metrics/MethodLength
           to_json_stream do |data|
+            next if data.nil?
+
             block.call(
               Chunk.new(
                 role: :assistant,

lib/ruby_llm/providers/openrouter/tools.rb

@@ -54,8 +54,12 @@ def parse_tool_calls(tool_calls, parse_arguments: true) # rubocop:disable Metric
                 id: tc['id'],
                 name: tc.dig('function', 'name'),
                 arguments: if parse_arguments
-                             JSON.parse(tc.dig('function',
-                                               'arguments'))
+                             begin
+                               JSON.parse(tc.dig('function',
+                                                 'arguments'))
+                             rescue JSON::ParserError
+                               {}
+                             end
                            else
                              tc.dig('function', 'arguments')
                            end