fix model server stop process (#217)

* fix model server stop process

* replace

* replace

* add test

* add multiple pids test

* add check install for linux

* reformat

model_server/app/tests/test_cli_stop_server.py

@@ -0,0 +1,55 @@
+import unittest
+from unittest.mock import patch, MagicMock
+import subprocess
+import time
+from app.cli import kill_process
+
+
+class TestStopServer(unittest.TestCase):
+    @patch("subprocess.run")
+    def test_stop_server_no_process(self, mock_run):
+        # Mock subprocess.run to simulate no process listening on the port
+        mock_run.return_value.returncode = 1
+        with patch("builtins.print") as mock_print:
+            kill_process(port=51000)
+            mock_print.assert_called_with("No process found listening on port 51000.")
+
+    @patch("subprocess.run")
+    def test_stop_server_process_killed(self, mock_run):
+        # Simulate lsof returning a process id
+        mock_run.side_effect = [
+            MagicMock(returncode=0, stdout="uvicorn 1234 user LISTEN\n"),
+            MagicMock(returncode=0),  # for killing the process
+            MagicMock(returncode=1),  # for checking the process after it is killed
+        ]
+        with patch("builtins.print") as mock_print:
+            kill_process(port=51000, wait=True, timeout=5)
+            mock_print.assert_any_call("Killing model server process with PID 1234")
+            mock_print.assert_any_call("Process 1234 has been killed.")
+
+    @patch("subprocess.run")
+    def test_stop_server_multiple_pids(self, mock_run):
+        # Simulate lsof returning multiple process ids (e.g., 1234 and 5678)
+        mock_run.side_effect = [
+            MagicMock(
+                returncode=0,
+                stdout="uvicorn 1234 user LISTEN\nuvicorn 5678 user LISTEN\n",
+            ),  # lsof output
+            MagicMock(returncode=0),  # first kill command for PID 1234
+            MagicMock(returncode=1),  # PID 1234 is successfully terminated
+            MagicMock(returncode=0),  # second kill command for PID 5678
+            MagicMock(returncode=1),  # PID 5678 is successfully terminated
+        ]
+
+        with patch("builtins.print") as mock_print:
+            kill_process(port=51000, wait=True, timeout=5)
+
+            # Assert that the function tried to kill both PIDs
+            mock_print.assert_any_call("Killing model server process with PID 1234")
+            mock_print.assert_any_call("Process 1234 has been killed.")
+            mock_print.assert_any_call("Killing model server process with PID 5678")
+            mock_print.assert_any_call("Process 5678 has been killed.")
+
+
+if __name__ == "__main__":
+    unittest.main()