From 2f210a420160db68c1c36981659dcbcc9736883a Mon Sep 17 00:00:00 2001
From: LeSingh1 <sshaurya914@gmail.com>
Date: Tue, 19 May 2026 17:47:49 -0700
Subject: [PATCH 1/2] test: add async fetch coverage for TimeWindow data source

---
 test/data/test_time_window.py | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/test/data/test_time_window.py b/test/data/test_time_window.py
index ad13a4d02..665ec4bbd 100644
--- a/test/data/test_time_window.py
+++ b/test/data/test_time_window.py
@@ -16,6 +16,7 @@
 
 """Tests for TimeWindow data wrapper."""
 
+import asyncio
 from datetime import datetime, timedelta
 
 import numpy as np
@@ -85,6 +86,10 @@ def __call__(self, time, variable):
             },
         )
 
+    async def fetch(self, time, variable):
+        """Mock async data fetch."""
+        return self(time, variable)
+
 
 class TestTimeWindowInitialization:
     """Test TimeWindow initialization and validation."""
@@ -357,6 +362,31 @@ def test_time_coordinate_alignment(self):
         assert len(result.time) == 1
         assert result.time.values[0] == np.datetime64(base_time)
 
+    def test_fetch_matches_sync_output_coordinates(self):
+        """Test async fetch applies offsets and preserves output coordinates."""
+        ds = MockDataSource()
+        tw = TimeWindow(
+            datasource=ds,
+            offsets=[timedelta(hours=-6), timedelta(hours=0), timedelta(hours=6)],
+            suffixes=["_tm1", "_t", "_tp1"],
+        )
+
+        base_time = datetime(2024, 1, 1, 12, 0)
+        result = asyncio.run(tw.fetch(base_time, ["t2m", "u10m"]))
+
+        expected_vars = [
+            "t2m_tm1",
+            "t2m_t",
+            "t2m_tp1",
+            "u10m_tm1",
+            "u10m_t",
+            "u10m_tp1",
+        ]
+        actual_vars = [str(v) for v in result.coords["variable"].values]
+        assert actual_vars == expected_vars
+        assert result.time.values[0] == np.datetime64(base_time)
+        assert ds.call_history[0]["time"] == [datetime(2024, 1, 1, 6, 0)]
+
 
 class TestTimeWindowErrorHandling:
     """Test error handling in TimeWindow."""

From 105f12aebaa18cc92e4afa6f50ba6eb01ed38d6c Mon Sep 17 00:00:00 2001
From: LeSingh1 <sshaurya914@gmail.com>
Date: Tue, 19 May 2026 18:09:00 -0700
Subject: [PATCH 2/2] test: align TimeWindow async fetch coverage

---
 test/data/test_time_window.py | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/test/data/test_time_window.py b/test/data/test_time_window.py
index 665ec4bbd..1e18405e0 100644
--- a/test/data/test_time_window.py
+++ b/test/data/test_time_window.py
@@ -16,7 +16,6 @@
 
 """Tests for TimeWindow data wrapper."""
 
-import asyncio
 from datetime import datetime, timedelta
 
 import numpy as np
@@ -362,7 +361,8 @@ def test_time_coordinate_alignment(self):
         assert len(result.time) == 1
         assert result.time.values[0] == np.datetime64(base_time)
 
-    def test_fetch_matches_sync_output_coordinates(self):
+    @pytest.mark.asyncio
+    async def test_fetch_matches_sync_output_coordinates(self):
         """Test async fetch applies offsets and preserves output coordinates."""
         ds = MockDataSource()
         tw = TimeWindow(
@@ -372,7 +372,7 @@ def test_fetch_matches_sync_output_coordinates(self):
         )
 
         base_time = datetime(2024, 1, 1, 12, 0)
-        result = asyncio.run(tw.fetch(base_time, ["t2m", "u10m"]))
+        result = await tw.fetch(base_time, ["t2m", "u10m"])
 
         expected_vars = [
             "t2m_tm1",
@@ -385,7 +385,9 @@ def test_fetch_matches_sync_output_coordinates(self):
         actual_vars = [str(v) for v in result.coords["variable"].values]
         assert actual_vars == expected_vars
         assert result.time.values[0] == np.datetime64(base_time)
-        assert ds.call_history[0]["time"] == [datetime(2024, 1, 1, 6, 0)]
+        assert ds.call_history[0]["time"] == [datetime(2024, 1, 1, 6, 0)]  # -6h
+        assert ds.call_history[1]["time"] == [datetime(2024, 1, 1, 12, 0)]  # 0h
+        assert ds.call_history[2]["time"] == [datetime(2024, 1, 1, 18, 0)]  # +6h
 
 
 class TestTimeWindowErrorHandling: