forgot file i moved the zarr tests to

virtualizarr/tests/test_writers/test_zarr.py

@@ -0,0 +1,85 @@
+import json
+
+import pytest
+from xarray import Dataset
+import xarray.testing as xrt
+import numpy as np
+
+from virtualizarr import ManifestArray
+
+from virtualizarr.writers.zarr import dataset_to_zarr
+from virtualizarr.manifests.manifest import ChunkManifest
+from virtualizarr import open_virtual_dataset
+from virtualizarr.backend import FileType
+from virtualizarr.readers.zarr import metadata_from_zarr_json
+from virtualizarr.writers.zarr import dataset_to_zarr
+
+
+@pytest.fixture
+def vds_with_manifest_arrays() -> Dataset:
+    arr = ManifestArray(
+        chunkmanifest=ChunkManifest(
+            entries={"0.0": dict(path="test.nc", offset=6144, length=48)}
+        ),
+        zarray=dict(
+            shape=(2, 3),
+            dtype=np.dtype("<i8"),
+            chunks=(2, 3),
+            compressor={"id": "zlib", "level": 1},
+            filters=None,
+            fill_value=0,
+            order="C",
+            zarr_format=3,
+        ),
+    )
+    return Dataset({"a": (["x", "y"], arr)}, attrs={"something": 0})
+
+
+def isconfigurable(value: dict) -> bool:
+    """
+    Several metadata attributes in ZarrV3 use a dictionary with keys "name" : str and "configuration" : dict
+    """
+    return "name" in value and "configuration" in value
+
+
+def test_zarr_v3_metadata_conformance(tmpdir, vds_with_manifest_arrays: Dataset):
+    """
+    Checks that the output metadata of an array variable conforms to this spec
+    for the required attributes:
+    https://zarr-specs.readthedocs.io/en/latest/v3/core/v3.0.html#metadata
+    """
+    dataset_to_zarr(vds_with_manifest_arrays, tmpdir / "store.zarr")
+    # read the a variable's metadata
+    with open(tmpdir / "store.zarr/a/zarr.json", mode="r") as f:
+        metadata = json.loads(f.read())
+    assert metadata["zarr_format"] == 3
+    assert metadata["node_type"] == "array"
+    assert isinstance(metadata["shape"], list) and all(
+        isinstance(dim, int) for dim in metadata["shape"]
+    )
+    assert isinstance(metadata["data_type"], str) or isconfigurable(
+        metadata["data_type"]
+    )
+    assert isconfigurable(metadata["chunk_grid"])
+    assert isconfigurable(metadata["chunk_key_encoding"])
+    assert isinstance(metadata["fill_value"], (bool, int, float, str, list))
+    assert (
+        isinstance(metadata["codecs"], list)
+        and len(metadata["codecs"]) > 1
+        and all(isconfigurable(codec) for codec in metadata["codecs"])
+    )
+
+
+def test_zarr_v3_roundtrip(tmpdir, vds_with_manifest_arrays: Dataset):
+    vds_with_manifest_arrays.virtualize.to_zarr(tmpdir / "store.zarr")
+    roundtrip = open_virtual_dataset(
+        tmpdir / "store.zarr", filetype=FileType.zarr_v3, indexes={}
+    )
+
+    xrt.assert_identical(roundtrip, vds_with_manifest_arrays)
+
+
+def test_metadata_roundtrip(tmpdir, vds_with_manifest_arrays: Dataset):
+    dataset_to_zarr(vds_with_manifest_arrays, tmpdir / "store.zarr")
+    zarray, _, _ = metadata_from_zarr_json(tmpdir / "store.zarr/a/zarr.json")
+    assert zarray == vds_with_manifest_arrays.a.data.zarray