fix(core): include container logs when container exits during log wait

src/testcontainers/core/wait_strategies.py

@@ -139,12 +139,16 @@ def wait_until_ready(self, container: "WaitStrategyTarget") -> None:
             wrapped.reload()
             if wrapped.status not in _NOT_EXITED_STATUSES:
                 # Get exit information for better debugging
+                stdout_str, stderr_str = _get_container_logs_for_debugging(container)
                 status_info = _get_container_status_info(container)
+                message_pattern = self._message.pattern if hasattr(self._message, "pattern") else str(self._message)
 
                 raise RuntimeError(
                     f"Container exited (status: {status_info['status']}, exit code: {status_info['exit_code']}) "
-                    f"before emitting logs containing '{self._message.pattern if hasattr(self._message, 'pattern') else str(self._message)}'. "
+                    f"before emitting logs containing '{message_pattern}'. "
                     f"Container error: {status_info['error']}. "
+                    f"Recent stdout: {stdout_str}. "
+                    f"Recent stderr: {stderr_str}. "
                     f"Hint: Check container logs and ensure the application is configured to start correctly. "
                     f"The application may be crashing or exiting early."
                 )

tests/core/test_wait_strategies.py

@@ -157,6 +157,30 @@ def test_wait_until_ready(self, mock_sleep, mock_time, container_logs, expected_
             with pytest.raises(TimeoutError):
                 strategy.wait_until_ready(mock_container)
 
+    @patch("time.sleep")
+    def test_wait_until_ready_includes_logs_when_container_exits(self, mock_sleep):
+        strategy = LogMessageWaitStrategy("waiting for connections")
+        mock_container = Mock()
+        mock_container.get_logs.return_value = (
+            b"Fatal: unknown option",
+            b"stderr diagnostic line",
+        )
+        mock_wrapped = Mock()
+        mock_wrapped.status = "exited"
+        mock_wrapped.reload.return_value = None
+        mock_container.get_wrapped_container.return_value = mock_wrapped
+
+        with patch(
+            "testcontainers.core.waiting_utils._get_container_status_info",
+            return_value={"status": "exited", "exit_code": "1", "error": "", "health_status": "none"},
+        ):
+            with pytest.raises(RuntimeError, match="Recent stdout: .*Fatal: unknown option") as exc_info:
+                strategy.wait_until_ready(mock_container)
+
+        error_message = str(exc_info.value)
+        assert "Recent stderr: stderr diagnostic line" in error_message
+        assert "exit code: 1" in error_message
+
 
 class TestHttpWaitStrategy:
     """Test the HttpWaitStrategy class."""