Add Docker exec PTY sessions

tests/test_docker_watcher.py

@@ -6,7 +6,12 @@ from unittest.mock import AsyncMock, MagicMock
 
 import pytest
 
-from webterm.docker_watcher import LABEL_NAME, THEME_LABEL, DockerWatcher, _get_auto_command
+from webterm.docker_watcher import (
+    AUTO_COMMAND_SENTINEL,
+    LABEL_NAME,
+    THEME_LABEL,
+    DockerWatcher,
+)
 
 
 @pytest.fixture
@@ -56,8 +61,7 @@ class TestDockerWatcher:
     def test_get_container_command_auto(self, docker_watcher):
         """Test command generation when label is 'auto'."""
         container = {"Names": ["/my-container"], "Labels": {LABEL_NAME: "auto"}}
-        expected = f"docker exec -it my-container {_get_auto_command()}"
-        assert docker_watcher._get_container_command(container) == expected
+        assert docker_watcher._get_container_command(container) == AUTO_COMMAND_SENTINEL
 
     def test_get_container_command_custom(self, docker_watcher):
         """Test command when label has custom value."""
@@ -93,7 +97,7 @@ class TestDockerWatcher:
         session_manager.add_app.assert_called_once()
         call_args = session_manager.add_app.call_args
         assert call_args[0][0] == "test-container"  # name
-        assert "docker exec -it test-container" in call_args[0][1]  # command
+        assert call_args[0][1] == AUTO_COMMAND_SENTINEL  # command
         assert call_args[0][2] == "test-container"  # slug
         assert call_args[1]["terminal"] is True
         assert call_args[1]["theme"] == "monokai"
@@ -235,8 +239,9 @@ class TestDockerWatcherIntegration:
     ("labels", "expected"),
     [
         ({"webterm-command": "echo hi"}, "echo hi"),
-        ({"webterm-command": "auto"}, f"docker exec -it my-container {_get_auto_command()}"),
-        ({"other": "value"}, f"docker exec -it my-container {_get_auto_command()}"),
+        ({"webterm-command": "auto"}, AUTO_COMMAND_SENTINEL),
+        ({"webterm-command": ""}, AUTO_COMMAND_SENTINEL),
+        ({"other": "value"}, AUTO_COMMAND_SENTINEL),
     ],
 )
 def test_get_container_command_variants(docker_watcher, labels, expected):
@@ -247,7 +252,7 @@ def test_get_container_command_variants(docker_watcher, labels, expected):
 def test_auto_command_env_override(monkeypatch, docker_watcher):
     monkeypatch.setenv("WEBTERM_DOCKER_AUTO_COMMAND", "/bin/sh")
     container = {"Names": ["/my-container"], "Labels": {LABEL_NAME: "auto"}}
-    assert docker_watcher._get_container_command(container) == "docker exec -it my-container /bin/sh"
+    assert docker_watcher._get_container_command(container) == AUTO_COMMAND_SENTINEL
 
 
 @pytest.mark.asyncio