Add thread safety tests (#275)

Author: sirwolfgang

test/features/thread_safety_test.rb

@@ -0,0 +1,189 @@
+# frozen_string_literal: true
+
+require "test_helper"
+
+# Tests to verify thread safety of the ActiveAgent framework.
+#
+# These tests address the concerns raised in GitHub issue #273 where
+# the old code had a race condition with shared provider instances.
+#
+# The refactored code should be thread-safe because:
+# 1. Each generation creates a new provider instance (not shared)
+# 2. No class-level mutable state that could be corrupted
+# 3. Each provider instance has its own context and message stack
+#
+# Reference: https://github.com/activeagents/activeagent/issues/273
+class ThreadSafetyTest < ActiveSupport::TestCase
+  # Test agent using Mock provider for fast, deterministic tests
+  class TestAgent < ActiveAgent::Base
+    generate_with :mock
+
+    def ask
+      prompt(message: params[:message])
+    end
+  end
+
+  # Agent with streaming support
+  class StreamingAgent < ActiveAgent::Base
+    generate_with :mock
+
+    attr_reader :stream_chunks
+
+    def initialize
+      super
+      @stream_chunks = []
+    end
+
+    on_stream do |chunk|
+      @stream_chunks << chunk.delta
+    end
+
+    def ask
+      prompt(message: params[:message], stream: true)
+    end
+  end
+
+  # Agent with tool support
+  class ToolAgent < ActiveAgent::Base
+    generate_with :mock
+
+    def ask
+      prompt(
+        message: params[:message],
+        tools: [ {
+          type: "function",
+          name: "get_data",
+          description: "Gets data for a location",
+          parameters: {
+            type: "object",
+            properties: {
+              location: { type: "string", description: "The location" }
+            },
+            required: [ "location" ]
+          }
+        } ]
+      )
+    end
+
+    private
+
+    def get_data(location:)
+      "Data for #{location}"
+    end
+  end
+
+  setup do
+    Thread.abort_on_exception = true
+  end
+
+  teardown do
+    Thread.abort_on_exception = false
+  end
+
+  private
+
+  # Helper to run concurrent operations and verify uniqueness
+  def run_concurrent(num_threads:, &block)
+    results = Concurrent::Array.new
+    threads = num_threads.times.map { |i| Thread.new { results << block.call(i) } }
+    threads.each(&:join)
+    results
+  end
+
+  def assert_unique_responses(results, message = "All responses should be unique")
+    responses = results.map { |r| r[:response] }
+    assert responses.all?(&:present?), "All threads should receive responses"
+    assert_equal results.size, responses.uniq.size, message
+  end
+
+  public
+
+  test "concurrent generations with different messages do not interfere" do
+    # Core issue from #273: multiple threads with different prompts
+    # should each get their own correct response back
+    results = run_concurrent(num_threads: 20) do |i|
+      message = "THREAD_#{i}: What is #{i} plus #{i}?"
+      response = TestAgent.with(message: message).ask.generate_now
+      { thread_id: i, response: response.message.content }
+    end
+
+    assert_unique_responses(results, "Duplicates indicate a race condition")
+  end
+
+  test "concurrent parameterized invocations with shared agent class" do
+    # Tests the common pattern of using .with() from multiple threads
+    results = run_concurrent(num_threads: 15) do |i|
+      message = "Request_#{i}_#{SecureRandom.hex(4)}"
+      response = TestAgent.with(message: message).ask.generate_now
+      { thread_id: i, response: response.message.content }
+    end
+
+    assert_unique_responses(results)
+  end
+
+  test "concurrent tool calls do not mix up parameters" do
+    # Tests tool calling scenario from issue #273
+    results = run_concurrent(num_threads: 10) do |i|
+      message = "Get data for Location_#{i}"
+      response = ToolAgent.with(message: message).ask.generate_now
+      { thread_id: i, response: response.message.content }
+    end
+
+    assert_unique_responses(results, "Tool responses should not mix between threads")
+  end
+
+  test "concurrent streaming generations maintain isolation" do
+    results = run_concurrent(num_threads: 5) do |i|
+      message = "Stream_#{i}_#{SecureRandom.hex(4)}"
+      response = StreamingAgent.with(message: message).ask.generate_now
+      { thread_id: i, response: response.message.content }
+    end
+
+    assert_unique_responses(results, "Streaming responses should not mix between threads")
+  end
+
+  test "high concurrency stress test" do
+    errors = Concurrent::Array.new
+    results = run_concurrent(num_threads: 50) do |i|
+      sleep(rand * 0.01) # Add timing variability
+      message = "Concurrent_#{i}_#{SecureRandom.uuid}"
+      response = TestAgent.with(message: message).ask.generate_now
+      { thread_id: i, response: response.message.content }
+    rescue => e
+      errors << { thread_id: i, error: e }
+      nil
+    end.compact
+
+    assert errors.empty?, "No threads should error: #{errors.inspect}"
+    assert_unique_responses(results, "Responses should be unique under high concurrency")
+  end
+
+  test "exception in one thread does not affect others" do
+    Thread.abort_on_exception = false
+
+    failing_agent_class = Class.new(TestAgent) do
+      def ask
+        raise "Intentional error" if params[:message].include?("FAIL")
+        super
+      end
+    end
+
+    results = run_concurrent(num_threads: 10) do |i|
+      message = i == 5 ? "FAIL_#{i}" : "Success_#{i}"
+      response = failing_agent_class.with(message: message).ask.generate_now
+      { thread_id: i, success: true, response: response.message.content }
+    rescue => e
+      { thread_id: i, success: false, error: e.message }
+    end
+
+    successful = results.select { |r| r[:success] }
+    failed = results.reject { |r| r[:success] }
+
+    assert_equal 9, successful.size, "9 threads should succeed"
+    assert_equal 1, failed.size, "1 thread should fail"
+    assert_equal 5, failed.first[:thread_id]
+    assert_unique_responses(successful)
+  ensure
+    Thread.abort_on_exception = true
+  end
+end