From 65ccef63f1f76eeea71720183cab5858dff929be Mon Sep 17 00:00:00 2001
From: Jason Munro <jmunro@lbl.gov>
Date: Wed, 26 Jan 2022 14:50:03 -0800
Subject: [PATCH] Fix and test num_chunks and num_workers error

---
 src/maggma/cli/distributed.py |  2 +-
 tests/cli/test_distributed.py | 18 ++++++++++++++++++
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/src/maggma/cli/distributed.py b/src/maggma/cli/distributed.py
index d29fbe72d..79a94d3b1 100644
--- a/src/maggma/cli/distributed.py
+++ b/src/maggma/cli/distributed.py
@@ -33,7 +33,7 @@ async def manager(
     """
     logger = getLogger("Manager")
 
-    if not num_chunks and num_workers:
+    if not (num_chunks and num_workers):
         raise ValueError("Both num_chunks and num_workers must be non-zero")
 
     logger.info(f"Binding to Manager URL {url}:{port}")
diff --git a/tests/cli/test_distributed.py b/tests/cli/test_distributed.py
index 26b9bfb51..89b9a7ba6 100644
--- a/tests/cli/test_distributed.py
+++ b/tests/cli/test_distributed.py
@@ -56,6 +56,24 @@ def process_items(self, items):
 SERVER_PORT = 8234
 
 
+@pytest.mark.xfail(raises=ValueError)
+@pytest.mark.asyncio
+async def test_wrong_worker_input(log_to_stdout):
+
+    manager_server = asyncio.create_task(
+        manager(
+            SERVER_URL,
+            SERVER_PORT,
+            [DummyBuilder(dummy_prechunk=False)],
+            num_chunks=2,
+            num_workers=0,
+        )
+    )
+
+    await asyncio.sleep(1)
+    manager_server.result()
+
+
 @pytest.mark.asyncio
 async def test_manager_give_out_chunks(log_to_stdout):