test(storage): add SupportsGetRanges conformance tests

Author: d-v-b

tests/test_store/test_protocols.py

@@ -0,0 +1,38 @@
+# tests/test_store/test_protocols.py
+"""Runtime and static conformance tests for zarr.storage._protocols.SupportsGetRanges."""
+
+from __future__ import annotations
+
+import pytest
+
+from zarr.storage._protocols import SupportsGetRanges
+
+
+def test_fsspec_store_satisfies_supports_get_ranges() -> None:
+    pytest.importorskip("fsspec")
+    from fsspec.implementations.memory import MemoryFileSystem
+
+    from zarr.storage import FsspecStore
+    from zarr.storage._fsspec import _make_async
+
+    fs = MemoryFileSystem()
+    fs.store.clear()
+    store = FsspecStore(fs=_make_async(fs), path="/x")
+    assert isinstance(store, SupportsGetRanges)
+
+
+def test_memory_store_does_not_satisfy_supports_get_ranges() -> None:
+    """Sanity check: stores that don't implement get_ranges shouldn't satisfy the protocol."""
+    from zarr.storage import MemoryStore
+
+    store = MemoryStore()
+    assert not isinstance(store, SupportsGetRanges)
+
+
+def test_type_assignment_at_module_level() -> None:
+    """Smoke-test the module-level `_: type[SupportsGetRanges] = FsspecStore`.
+
+    If this runs without error the module imported cleanly; the static check is in mypy.
+    """
+    pytest.importorskip("fsspec")
+    from zarr.storage import _fsspec  # noqa: F401