diff --git a/tests/test_run_server.py b/tests/test_run_server.py
new file mode 100644
index 00000000..849af329
--- /dev/null
+++ b/tests/test_run_server.py
@@ -0,0 +1,138 @@
+# Copyright 2024 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import unittest
+from unittest.mock import patch, MagicMock
+from absl import app
+from absl.testing import flagsaver
+from parameterized import parameterized, param
+
+
+class MockServer(MagicMock):
+
+  def run(self, **kwargs):
+    return self
+
+  def wait_for_termination(self):
+    raise SystemExit("Successfully exited test.")
+
+
+def mock_engine(**kwargs):
+  return kwargs
+
+
+class ServerRunTest(unittest.TestCase):
+
+  def reset_flags(self):
+    flagsaver.restore_flag_values(self.original)
+
+  def setup(self):
+    from run_server import flags
+
+    FLAGS = flags.FLAGS
+    self.original = flagsaver.save_flag_values()
+    return FLAGS
+
+  @parameterized.expand(
+      [
+          param(["test1", "--model_name", "llama-3"], "llama-3"),
+          param(["test2", "--model_name", "llama-2"], "llama-2"),
+          param(["test3", "--model_name", "mixtral"], "mixtral"),
+          param(["test4", "--model_name", "gemma"], "gemma"),
+      ]
+  )
+  @patch("jetstream_pt.engine.create_pytorch_engine", mock_engine)
+  @patch("jetstream.core.server_lib.run", MockServer().run)
+  def test_no_change_from_defaults(self, args, expected):
+    """test defaults remain unchanged when launching a server for different models.
+
+    Args:
+        args (List): List to simulate sys.argv with dummy first entry at index 0.
+        expected (str): model_name flag value to inspect
+    """
+    from run_server import main
+
+    FLAGS = self.setup()
+    with self.assertRaisesRegex(SystemExit, "Successfully exited test."):
+      app.run(main, args)
+
+    # run_server
+    self.assertEqual(FLAGS.port, 9000)
+    self.assertEqual(FLAGS.threads, 64)
+    self.assertEqual(FLAGS.config, "InterleavedCPUTestServer")
+    self.assertEqual(FLAGS.prometheus_port, 0)
+    self.assertEqual(FLAGS.enable_jax_profiler, False)
+    self.assertEqual(FLAGS.jax_profiler_port, 9999)
+
+    # quantization configs
+    self.assertEqual(FLAGS.quantize_weights, False)
+    self.assertEqual(FLAGS.quantize_activation, False)
+    self.assertEqual(FLAGS.quantize_type, "int8_per_channel")
+    self.assertEqual(FLAGS.quantize_kv_cache, False)
+
+    # engine configs
+    self.assertEqual(FLAGS.tokenizer_path, None)
+    self.assertEqual(FLAGS.checkpoint_path, None)
+    self.assertEqual(FLAGS.bf16_enable, True)
+    self.assertEqual(FLAGS.context_length, 1024)
+    self.assertEqual(FLAGS.batch_size, 32)
+    self.assertEqual(FLAGS.size, "tiny")
+    self.assertEqual(FLAGS.max_cache_length, 1024)
+    self.assertEqual(FLAGS.shard_on_batch, False)
+    self.assertEqual(FLAGS.sharding_config, "")
+    self.assertEqual(FLAGS.ragged_mha, False)
+    self.assertEqual(FLAGS.starting_position, 512)
+    self.assertEqual(FLAGS.temperature, 1.0)
+    self.assertEqual(FLAGS.sampling_algorithm, "greedy")
+    self.assertEqual(FLAGS.nucleus_topp, 0.0)
+    self.assertEqual(FLAGS.topk, 0)
+    self.assertEqual(FLAGS.ring_buffer, True)
+
+    # profiling configs
+    self.assertEqual(FLAGS.profiling_prefill, False)
+    self.assertEqual(FLAGS.profiling_output, "")
+
+    # model_name flag updates
+    self.assertEqual(FLAGS.model_name, expected)
+
+    # reset back to original flags
+    self.reset_flags()
+
+  @parameterized.expand([param(["test1", "--model_name", "llama3"])])
+  @patch("jetstream_pt.engine.create_pytorch_engine", mock_engine)
+  def test_call_server_object(self, args):
+    """tests whether running the main script from absl.app.run launches a server and waits for termination
+
+    Args:
+        args (List): List to simulate sys.argv with dummy first entry at index 0.
+    """
+    with patch(
+        "jetstream.core.server_lib.run", autospec=MockServer().run
+    ) as mock_server:
+      from run_server import main
+
+      FLAGS = self.setup()
+      with self.assertRaises(SystemExit):
+        app.run(main, args)
+      self.assertEqual(mock_server.call_count, 1)
+      self.assertEqual(
+          mock_server.return_value.wait_for_termination.call_count, 1
+      )
+
+      # reset back to original flags
+      self.reset_flags()
+
+
+if __name__ == "__main__":
+  unittest.main()