contours: validate input raster, reject complex dtype

xrspatial/contour.py

@@ -13,7 +13,7 @@
 import numpy as np
 import xarray as xr
 
-from .utils import ArrayTypeFunctionMapping, ngjit
+from .utils import ArrayTypeFunctionMapping, _validate_raster, ngjit
 
 try:
     import dask
@@ -602,8 +602,7 @@ def contours(
     >>> # Each entry is (level_value, Nx2_coordinate_array)
     >>> level, coords = lines[0]
     """
-    if agg.ndim != 2:
-        raise ValueError("Input raster must be 2D")
+    _validate_raster(agg, func_name='contours', name='agg', ndim=2)
     if agg.shape[0] < 2 or agg.shape[1] < 2:
         raise ValueError(
             "Input raster must have at least 2 rows and 2 columns"

xrspatial/tests/test_contour.py

@@ -180,6 +180,19 @@ def test_too_small(self):
         with pytest.raises(ValueError, match="at least 2"):
             contours(agg, levels=[0.5])
 
+    def test_complex_dtype_rejected(self):
+        """Complex input raises instead of silently dropping the imaginary part."""
+        data = np.ones((3, 3), dtype=np.complex128)
+        agg = xr.DataArray(data, dims=['y', 'x'])
+        with pytest.raises(ValueError, match="real numeric"):
+            contours(agg, levels=[0.5])
+
+    def test_non_dataarray_rejected(self):
+        """A plain ndarray raises a clear TypeError, not a late dispatch error."""
+        data = np.ones((3, 3), dtype=np.float64)
+        with pytest.raises(TypeError, match="xarray.DataArray"):
+            contours(data, levels=[0.5])
+
 
 # ---------------------------------------------------------------------------
 # Segment stitching