Handle case of no compressors in get_compressor_config

Author: tomwhite

bio2zarr/zarr_utils.py

@@ -197,6 +197,8 @@ def get_compressor(array):
 
 def get_compressor_config(array):
     compressor = get_compressor(array)
+    if compressor is None:
+        return None
     # numcodecs codecs (zarr format v2 path) expose get_config directly.
     if hasattr(compressor, "get_config"):
         return compressor.get_config()

tests/test_zarr_utils.py

@@ -549,6 +549,12 @@ class Stub:
         assert config["cname"] == "zstd"
         assert config["clevel"] == 4
 
+    def test_no_compressors(self):
+        class Stub:
+            compressors = ()
+
+        assert zarr_utils.get_compressor_config(Stub()) is None
+
     def test_unsupported_type_raises(self):
         class FakeCodec:
             pass