Cover read_vrt GPU/dask+GPU paths and a few VRT parameter combos (#1619)

.claude/sweep-test-coverage-state.csv

@@ -1,3 +1,3 @@
-module,last_inspected,issue,severity_max,categories_found,notes
-geotiff,2026-05-11,,MEDIUM,4,"Sweep 2 (2026-05-11): added test_streaming_codecs_2026_05_11.py covering dask streaming write + LERC (lossless/lossy/eager-parity), LZ4, packbits, and COG overview_resampling='cubic' (scipy code path). Prior HIGH gaps from PR #1565 remain closed (dask+planar multiband, dask+overview_level, predictor=2 int8 CPU+GPU, dask chunk-vs-tile misalignment). No HIGH gaps remain."
-reproject,2026-05-10,,HIGH,1;4;5,"Added 39 tests: LiteCRS direct coverage, itrf_transform behaviour/roundtrip/array, itrf_frames, geoid_height numerical correctness + raster happy-path, vertical helpers (ellipsoidal<->orthometric/depth), reproject() lat/lon and latitude/longitude dim propagation. Note: _merge_arrays_cupy is imported but unused (no cupy merge dispatch in merge()); flagged as feature gap not test gap."
+module,last_inspected,issue,severity_max,categories_found,notes
+geotiff,2026-05-11,,MEDIUM,1;4,"Sweep 3 (2026-05-11 r3): added test_vrt_backend_coverage_2026_05_11.py closing read_vrt(gpu=True) + read_vrt(gpu=True, chunks=N) (Cat 1, dask+cupy backend), read_vrt(dtype=) safe-widening and float->int validation (Cat 4), read_vrt(name=) override (Cat 4), and open_geotiff(BytesIO, gpu=True) / open_geotiff(BytesIO, chunks=N) error-path coverage (Cat 4). 11 tests, all passing on GPU host. No HIGH gaps remain."
+reproject,2026-05-10,,HIGH,1;4;5,"Added 39 tests: LiteCRS direct coverage, itrf_transform behaviour/roundtrip/array, itrf_frames, geoid_height numerical correctness + raster happy-path, vertical helpers (ellipsoidal<->orthometric/depth), reproject() lat/lon and latitude/longitude dim propagation. Note: _merge_arrays_cupy is imported but unused (no cupy merge dispatch in merge()); flagged as feature gap not test gap."

xrspatial/geotiff/tests/test_vrt_backend_coverage_2026_05_11.py

@@ -0,0 +1,245 @@
+"""Backend / parameter coverage for the VRT read path.
+
+The non-VRT read backends (``open_geotiff`` / ``read_geotiff_dask`` /
+``read_geotiff_gpu``) all have dedicated multi-backend coverage; the
+VRT route through ``read_vrt`` historically lacked it. The eager
+numpy path has dense coverage, but the GPU and dask+GPU paths the
+``read_vrt`` body explicitly handles (the ``if gpu: cupy.asarray``
+and trailing ``result.chunk(...)`` blocks) were only reachable
+indirectly via ``open_geotiff('.vrt', gpu=True)`` / ``..., chunks=N)``
+and went untested.
+
+The error-rejection branches for file-like sources combined with
+``gpu=True`` / ``chunks=N`` on ``open_geotiff`` were likewise covered
+only by inspection.
+
+Test coverage gap sweep 2026-05-11 (pass 3): close the VRT backend
+coverage gap and the file-like-rejection parameter gaps.
+"""
+from __future__ import annotations
+
+import importlib.util
+import io
+import os
+
+import numpy as np
+import pytest
+import xarray as xr
+
+from xrspatial.geotiff import open_geotiff, read_vrt, to_geotiff
+from xrspatial.geotiff._vrt import write_vrt as _write_vrt_internal
+
+
+# ---------------------------------------------------------------------------
+# CUDA gating: GPU tests share a skip predicate with the rest of the
+# geotiff test suite. The token "cuda-unavailable" in the state CSV
+# notes column flags a re-run on a GPU host when a non-CUDA sweep
+# added these tests.
+# ---------------------------------------------------------------------------
+
+def _cuda_available() -> bool:
+    if importlib.util.find_spec("cupy") is None:
+        return False
+    try:
+        import cupy
+        return bool(cupy.cuda.is_available())
+    except Exception:
+        return False
+
+
+_HAS_CUDA = _cuda_available()
+_gpu_only = pytest.mark.skipif(not _HAS_CUDA, reason="cupy + CUDA required")
+
+
+# ---------------------------------------------------------------------------
+# Fixtures
+# ---------------------------------------------------------------------------
+
+@pytest.fixture
+def single_tile_vrt(tmp_path):
+    """A trivial single-tile VRT plus its source array.
+
+    Float32 source so the VRT band advertises Float32 and the eager
+    numpy read returns float32 (lets dtype-cast tests assert a real
+    type change).
+    """
+    arr = np.arange(16, dtype=np.float32).reshape(4, 4)
+    tile_path = str(tmp_path / 'tile.tif')
+    to_geotiff(arr, tile_path)
+    vrt_path = str(tmp_path / 'mosaic.vrt')
+    _write_vrt_internal(vrt_path, [tile_path])
+    return vrt_path, arr
+
+
+# ---------------------------------------------------------------------------
+# Cat 1: read_vrt backend coverage (GPU + dask+GPU)
+# ---------------------------------------------------------------------------
+
+@_gpu_only
+class TestReadVrtGpuBackend:
+    """``read_vrt(gpu=True)`` returns a CuPy-backed DataArray.
+
+    The eager VRT decode runs on the CPU (the VRT internal reader
+    walks SimpleSources and assembles via windowed reads) then the
+    final ``if gpu: arr = cupy.asarray(arr)`` block transfers to GPU.
+    A regression that dropped the transfer block would have shipped
+    a numpy DataArray instead of a CuPy one; this test pins that.
+    """
+
+    def test_read_vrt_gpu_returns_cupy(self, single_tile_vrt):
+        import cupy
+
+        vrt_path, arr = single_tile_vrt
+        da = read_vrt(vrt_path, gpu=True)
+        assert isinstance(da.data, cupy.ndarray), (
+            f"expected cupy.ndarray, got {type(da.data).__name__}"
+        )
+        np.testing.assert_array_equal(da.data.get(), arr)
+
+    def test_read_vrt_gpu_chunks_returns_dask_cupy(self, single_tile_vrt):
+        """``read_vrt(gpu=True, chunks=N)`` is the documented dask+cupy
+        VRT entry point. The trailing ``result.chunk(...)`` block has
+        to wrap the cupy backing without falling back to numpy.
+        """
+        import cupy
+        import dask.array as da_mod
+
+        vrt_path, arr = single_tile_vrt
+        result = read_vrt(vrt_path, gpu=True, chunks=2)
+
+        assert isinstance(result.data, da_mod.Array), (
+            f"expected dask Array, got {type(result.data).__name__}"
+        )
+        # _meta tells distributed Dask the underlying array is cupy.
+        # A numpy meta here would cause optimizers to silently move
+        # data back to host.
+        assert isinstance(result.data._meta, cupy.ndarray), (
+            f"expected cupy._meta, got "
+            f"{type(result.data._meta).__module__}."
+            f"{type(result.data._meta).__name__}"
+        )
+        # Chunks honour the spatial spec; the band axis (absent here)
+        # would chunk as a single block.
+        assert result.data.chunks == ((2, 2), (2, 2))
+
+        computed = result.compute()
+        assert isinstance(computed.data, cupy.ndarray)
+        np.testing.assert_array_equal(computed.data.get(), arr)
+
+    def test_open_geotiff_vrt_gpu_routes_through(self, single_tile_vrt):
+        """``open_geotiff('.vrt', gpu=True)`` dispatches to ``read_vrt``
+        and surfaces the cupy data unchanged. The dispatcher branch
+        is one line in ``open_geotiff`` but a refactor that dropped
+        ``gpu=gpu`` from the forwarded kwargs would silently produce
+        a numpy DataArray.
+        """
+        import cupy
+
+        vrt_path, arr = single_tile_vrt
+        da = open_geotiff(vrt_path, gpu=True)
+        assert isinstance(da.data, cupy.ndarray)
+        np.testing.assert_array_equal(da.data.get(), arr)
+
+    def test_open_geotiff_vrt_gpu_chunks(self, single_tile_vrt):
+        """``open_geotiff('.vrt', gpu=True, chunks=N)`` is the combined
+        dask+cupy entry point. Same dispatch test as the gpu-only
+        variant but also pins the chunk forwarding.
+        """
+        import cupy
+        import dask.array as da_mod
+
+        vrt_path, arr = single_tile_vrt
+        result = open_geotiff(vrt_path, gpu=True, chunks=2)
+
+        assert isinstance(result.data, da_mod.Array)
+        assert isinstance(result.data._meta, cupy.ndarray)
+        assert result.data.chunks == ((2, 2), (2, 2))
+
+        computed = result.compute()
+        np.testing.assert_array_equal(computed.data.get(), arr)
+
+
+# ---------------------------------------------------------------------------
+# Cat 4: read_vrt parameter coverage (dtype / name)
+# ---------------------------------------------------------------------------
+
+class TestReadVrtDtypeKwarg:
+    """``read_vrt(dtype=...)`` casts after decode and validates the cast."""
+
+    def test_safe_widening_cast(self, single_tile_vrt):
+        """float32 -> float64 is permitted; values survive bit-for-bit."""
+        vrt_path, arr = single_tile_vrt
+        da = read_vrt(vrt_path, dtype='float64')
+        assert da.dtype == np.float64
+        np.testing.assert_array_equal(da.values, arr.astype(np.float64))
+
+    def test_float_to_int_rejected(self, single_tile_vrt):
+        """Float-to-int is lossy and refused with a descriptive error.
+        Mirrors ``open_geotiff(dtype=...)`` behaviour so callers see the
+        same gate on both entry points.
+        """
+        vrt_path, _ = single_tile_vrt
+        with pytest.raises(ValueError, match="Cannot cast float"):
+            read_vrt(vrt_path, dtype='int32')
+
+
+class TestReadVrtNameKwarg:
+    """``read_vrt(name='custom')`` overrides the file-stem derivation."""
+
+    def test_explicit_name_used(self, single_tile_vrt):
+        vrt_path, _ = single_tile_vrt
+        da = read_vrt(vrt_path, name='custom_name')
+        assert da.name == 'custom_name'
+
+    def test_default_name_from_stem(self, single_tile_vrt):
+        vrt_path, _ = single_tile_vrt
+        da = read_vrt(vrt_path)
+        # mosaic.vrt -> mosaic
+        assert da.name == os.path.splitext(os.path.basename(vrt_path))[0]
+
+
+# ---------------------------------------------------------------------------
+# Cat 4: open_geotiff file-like + backend kwarg rejection
+# ---------------------------------------------------------------------------
+
+class TestOpenGeotiffFileLikeKwargRejection:
+    """File-like sources reject ``gpu=True`` and ``chunks=N`` up front.
+
+    The check sits in ``open_geotiff`` (not the underlying readers)
+    because both downstream paths re-open the source by path from
+    worker tasks. A buffer passed through would either raise deep
+    inside dask graph construction or silently behave as if the
+    buffer were a string path.
+    """
+
+    @staticmethod
+    def _buf_with_tiff(tmp_path):
+        arr = np.zeros((4, 4), dtype=np.float32)
+        path = str(tmp_path / 'src.tif')
+        to_geotiff(arr, path)
+        with open(path, 'rb') as fh:
+            return io.BytesIO(fh.read())
+
+    def test_gpu_with_file_like_raises(self, tmp_path):
+        buf = self._buf_with_tiff(tmp_path)
+        with pytest.raises(ValueError, match="gpu=True is not supported"):
+            open_geotiff(buf, gpu=True)
+
+    def test_chunks_with_file_like_raises(self, tmp_path):
+        buf = self._buf_with_tiff(tmp_path)
+        with pytest.raises(ValueError, match="chunks=.*file-like"):
+            open_geotiff(buf, chunks=64)
+
+    def test_chunks_with_pathlib_path_still_works(self, tmp_path):
+        """Sanity-check: pathlib.Path is not file-like and must keep
+        working through the dask path. Otherwise the file-like gate
+        would also lock out Path inputs.
+        """
+        arr = np.arange(16, dtype=np.float32).reshape(4, 4)
+        path = tmp_path / 'sample.tif'
+        to_geotiff(arr, str(path))
+
+        import dask.array as da_mod
+        result = open_geotiff(path, chunks=2)
+        assert isinstance(result.data, da_mod.Array)
+        np.testing.assert_array_equal(np.asarray(result.data), arr)