test: add icon cross_section test case

Author: rajeeja

test/io/test_icon.py

@@ -8,3 +8,17 @@ def test_read_icon_grid(gridpath):
 def test_read_icon_dataset(gridpath):
     grid_path = gridpath("icon", "R02B04", "icon_grid_0010_R02B04_G.nc")
     uxds = ux.open_dataset(grid_path, grid_path)
+
+def test_icon_cross_section(gridpath):
+    grid_path = gridpath("icon", "R02B04", "icon_grid_0010_R02B04_G.nc")
+    uxds = ux.open_dataset(grid_path, grid_path)
+
+    # Test cross_section with cell_area variable
+    result = uxds.cell_area.cross_section(start=(0, -90), end=(0, 90))
+    assert result is not None
+    assert len(result) == 100  # 100 steps by default
+    assert result.dims == ('steps',)
+    assert all(result.coords['lon'] == 0.0)  # Constant longitude
+    assert result.coords['lat'].min() == -90.0
+    assert result.coords['lat'].max() == 90.0
+    assert result.attrs['units'] == 'steradian'