diff --git a/litellm/tests/test_router_max_parallel_requests.py b/litellm/tests/test_router_max_parallel_requests.py
new file mode 100644
index 0000000000..43c3694ff7
--- /dev/null
+++ b/litellm/tests/test_router_max_parallel_requests.py
@@ -0,0 +1,53 @@
+# What is this?
+## Unit tests for the max_parallel_requests feature on Router
+import sys, os, time, inspect, asyncio, traceback
+from datetime import datetime
+import pytest
+
+sys.path.insert(0, os.path.abspath("../.."))
+import litellm
+from litellm.utils import calculate_max_parallel_requests
+
+"""
+- only rpm
+- only tpm
+- only max_parallel_requests 
+- max_parallel_requests + rpm 
+- max_parallel_requests + tpm
+- max_parallel_requests + tpm + rpm 
+"""
+
+
+max_parallel_requests_values = [None, 10]
+tpm_values = [None, 20]
+rpm_values = [None, 30]
+default_max_parallel_requests = [None, 40]
+
+
+@pytest.mark.parametrize(
+    "max_parallel_requests, tpm, rpm, default_max_parallel_requests",
+    [
+        (mp, tp, rp, dmp)
+        for mp in max_parallel_requests_values
+        for tp in tpm_values
+        for rp in rpm_values
+        for dmp in default_max_parallel_requests
+    ],
+)
+def test_scenario(max_parallel_requests, tpm, rpm, default_max_parallel_requests):
+    calculated_max_parallel_requests = calculate_max_parallel_requests(
+        max_parallel_requests=max_parallel_requests,
+        rpm=rpm,
+        tpm=tpm,
+        default_max_parallel_requests=default_max_parallel_requests,
+    )
+    if max_parallel_requests is not None:
+        assert max_parallel_requests == calculated_max_parallel_requests
+    elif rpm is not None:
+        assert rpm == calculated_max_parallel_requests
+    elif tpm is not None:
+        assert int(tpm / 1000 / 6) == calculated_max_parallel_requests
+    elif default_max_parallel_requests is not None:
+        assert calculated_max_parallel_requests == default_max_parallel_requests
+    else:
+        assert calculated_max_parallel_requests is None