FSStore: key_separator fix (#699)

* key_separator: failing tests

* key_separator: fix handling of meta keys

This rebases and cleans a fix from Martin's original PR.
Two new test methods fail without it and pass with since
keys for meta-files like `.zarray` were being converted
into `/zarray`.

see: martindurant@5795bc7

Author: joshmoore

zarr/storage.py

@@ -1020,6 +1020,8 @@ class FSStore(MutableMapping):
     storage_options : passed to the fsspec implementation
     """
 
+    _META_KEYS = (attrs_key, group_meta_key, array_meta_key)
+
     def __init__(self, url, normalize_keys=True, key_separator='.',
                  mode='w',
                  exceptions=(KeyError, PermissionError, IOError),
@@ -1039,7 +1041,11 @@ def _normalize_key(self, key):
         key = normalize_storage_path(key).lstrip('/')
         if key:
             *bits, end = key.split('/')
-            key = '/'.join(bits + [end.replace('.', self.key_separator)])
+
+            if end not in FSStore._META_KEYS:
+                end = end.replace('.', self.key_separator)
+                key = '/'.join(bits + [end])
+
         return key.lower() if self.normalize_keys else key
 
     def getitems(self, keys, **kwargs):

zarr/tests/test_storage.py

@@ -863,12 +863,27 @@ def mock_walker_no_slash(_path):
 @pytest.mark.skipif(have_fsspec is False, reason="needs fsspec")
 class TestFSStore(StoreTests, unittest.TestCase):
 
-    def create_store(self, normalize_keys=False):
+    def create_store(self, normalize_keys=False, key_separator="."):
         path = tempfile.mkdtemp()
         atexit.register(atexit_rmtree, path)
-        store = FSStore(path, normalize_keys=normalize_keys)
+        store = FSStore(
+            path,
+            normalize_keys=normalize_keys,
+            key_separator=key_separator)
         return store
 
+    def test_key_separator(self):
+        for x in (".", "/"):
+            store = self.create_store(key_separator=x)
+            norm = store._normalize_key
+            assert ".zarray" == norm(".zarray")
+            assert ".zarray" == norm("/.zarray")
+            assert ".zgroup" == norm("/.zgroup")
+            assert "group/.zarray" == norm("group/.zarray")
+            assert "group/.zgroup" == norm("group/.zgroup")
+            assert "group/.zarray" == norm("/group/.zarray")
+            assert "group/.zgroup" == norm("/group/.zgroup")
+
     def test_complex(self):
         path1 = tempfile.mkdtemp()
         path2 = tempfile.mkdtemp()
@@ -1183,13 +1198,27 @@ def test_filters(self):
 @pytest.mark.skipif(have_fsspec is False, reason="needs fsspec")
 class TestNestedFSStore(TestNestedDirectoryStore):
 
-    def create_store(self, normalize_keys=False):
-        path = tempfile.mkdtemp()
+    def create_store(self, normalize_keys=False, path=None):
+        if path is None:
+            path = tempfile.mkdtemp()
         atexit.register(atexit_rmtree, path)
         store = FSStore(path, normalize_keys=normalize_keys,
                         key_separator='/', auto_mkdir=True)
         return store
 
+    def test_numbered_groups(self):
+        import zarr
+
+        # Create an array
+        store = self.create_store()
+        group = zarr.group(store=store)
+        arr = group.create_dataset('0', shape=(10, 10))
+        arr[1] = 1
+
+        # Read it back
+        store = self.create_store(path=store.path)
+        zarr.open_group(store.path)["0"]
+
 
 class TestTempStore(StoreTests, unittest.TestCase):