Some buffer coverage

Author: TomAugspurger

src/zarr/core/buffer/gpu.py

@@ -52,7 +52,7 @@ class Buffer(core.Buffer):
 
     def __init__(self, array_like: ArrayLike) -> None:
         if cp is None:
-            raise ImportError(
+            raise ImportError(  # pragma: no cover
                 "Cannot use zarr.buffer.gpu.Buffer without cupy. Please install cupy."
             )
 
@@ -141,7 +141,7 @@ class NDBuffer(core.NDBuffer):
 
     def __init__(self, array: NDArrayLike) -> None:
         if cp is None:
-            raise ImportError(
+            raise ImportError(  # pragma: no cover
                 "Cannot use zarr.buffer.gpu.NDBuffer without cupy. Please install cupy."
             )
 

tests/test_buffer.py

@@ -186,6 +186,19 @@ def test_numpy_buffer_prototype() -> None:
         ndbuffer.as_scalar()
 
 
+@gpu_test
+def test_gpu_buffer_raises() -> None:
+    import cupy as cp
+
+    arr = cp.empty((10, 10), dtype="B")
+    with pytest.raises(ValueError, match="array_like: only 1-dim allowed"):
+        gpu.Buffer(arr)
+
+    arr = cp.arange(12, dtype="int32")
+    with pytest.raises(ValueError, match="array_like: only byte dtype allowed"):
+        gpu.Buffer(arr)
+
+
 @gpu_test
 def test_gpu_buffer_prototype() -> None:
     buffer = gpu.buffer_prototype.buffer.create_zero_length()