diff --git a/tests/data/raster/data.py b/tests/data/raster/data.py
index c6328b204..cc00aafef 100644
--- a/tests/data/raster/data.py
+++ b/tests/data/raster/data.py
@@ -31,7 +31,7 @@ def generate_test_data(fn: str) -> str:
     }
 
     with rasterio.open(fn, "w", **profile) as f:
-        f.write(np.random.randint(0, 2**32 - 1, size=(1, 4, 4)))
+        f.write(np.random.randint(0, 256, size=(1, 4, 4)))
 
     md5: str = calculate_md5(fn)
     return md5
diff --git a/tests/data/raster/test0.tif b/tests/data/raster/test0.tif
index 83d75bbdc..84df1f7cb 100644
Binary files a/tests/data/raster/test0.tif and b/tests/data/raster/test0.tif differ
diff --git a/tests/datasets/test_geo.py b/tests/datasets/test_geo.py
index 0cc949664..2035e8523 100644
--- a/tests/datasets/test_geo.py
+++ b/tests/datasets/test_geo.py
@@ -193,6 +193,12 @@ class TestRasterDataset:
         with pytest.raises(FileNotFoundError, match="No RasterDataset data was found"):
             RasterDataset(str(tmp_path))
 
+    def test_plot_with_cmap(self, custom_dtype_ds: RasterDataset) -> None:
+        custom_dtype_ds.cmap = {i: (0, 0, 0, 255) for i in range(256)}
+        custom_dtype_ds.is_image = False
+        x = custom_dtype_ds[custom_dtype_ds.bounds]
+        custom_dtype_ds.plot(x["mask"])
+
 
 class TestVectorDataset:
     @pytest.fixture