Configuration option for number of concurrent requests

tests/test_label_timeouts.py

@@ -1,13 +1,13 @@
 import io
 import tempfile
 import unittest
-from concurrent.futures import wait as real_wait
+from concurrent.futures import ThreadPoolExecutor, wait as real_wait
 from contextlib import redirect_stdout
 from pathlib import Path
 from threading import Event
 from unittest.mock import Mock, patch
 
-from copienator import EvaluationWorkspace, ExitCode
+from copienator import CliError, EvaluationWorkspace, ExitCode
 from copienator.commands import gemini_for_labels as labels
 
 
@@ -36,6 +36,33 @@ class LabelTimeoutTests(unittest.TestCase):
             sleep=lambda _: None, target_interval=0,
         )
 
+    def test_cli_forwards_selected_concurrency(self):
+        for arguments, expected in (([], 12), (["--workers", "2"], 2)):
+            with self.subTest(arguments=arguments), \
+                    patch.object(labels, "run", return_value=ExitCode.SUCCESS) as run:
+                self.assertEqual(labels.main([str(self.workspace.root), *arguments]), 0)
+                run.assert_called_once_with(
+                    unittest.mock.ANY, [self.workspace.root],
+                    overwrite=False, max_workers=expected,
+                )
+
+    def test_selected_concurrency_controls_executor(self):
+        self.client.models.generate_content.return_value = self.response
+        with patch.object(labels, "selected_images", return_value=(self.images, [])), \
+                patch.object(labels, "ThreadPoolExecutor", wraps=ThreadPoolExecutor) as executor:
+            result = labels.run(self.workspace, [], client=self.client,
+                                sleep=lambda _: None, max_workers=1)
+        self.assertEqual(result, ExitCode.SUCCESS)
+        executor.assert_called_once_with(max_workers=1)
+        self.assertEqual(self.client.models.generate_content.call_count, 3)
+
+    def test_nonpositive_concurrency_rejected_before_requests(self):
+        for workers in (0, -1):
+            with self.subTest(workers=workers), self.assertRaises(CliError) as caught:
+                labels.run(self.workspace, [], client=self.client, max_workers=workers)
+            self.assertEqual(caught.exception.exit_code, ExitCode.INVALID_ARGUMENTS)
+        self.client.models.generate_content.assert_not_called()
+
     def test_timeout_recovery_uses_bounded_requests_and_saves_result(self):
         self.client.models.generate_content.side_effect = [TimeoutError(), self.response]
         self.assertEqual(self.group(self.images[:1]), 1)