diff --git a/src/zarr/testing/stateful.py b/src/zarr/testing/stateful.py
index acc5f63f19..f4f7b33318 100644
--- a/src/zarr/testing/stateful.py
+++ b/src/zarr/testing/stateful.py
@@ -17,6 +17,7 @@
 import zarr
 from zarr import Array
 from zarr.abc.store import Store
+from zarr.codecs.bytes import BytesCodec
 from zarr.core.buffer import Buffer, BufferPrototype, cpu, default_buffer_prototype
 from zarr.core.sync import SyncMixin
 from zarr.storage import LocalStore, MemoryStore
@@ -108,7 +109,15 @@ def add_array(
         assume(self.can_add(path))
         note(f"Adding array:  path='{path}'  shape={array.shape}  chunks={chunks}")
         for store in [self.store, self.model]:
-            zarr.array(array, chunks=chunks, path=path, store=store, fill_value=fill_value)
+            zarr.array(
+                array,
+                chunks=chunks,
+                path=path,
+                store=store,
+                fill_value=fill_value,
+                # Chose bytes codec to avoid wasting time compressing the data being written
+                codecs=[BytesCodec()],
+            )
         self.all_arrays.add(path)
 
     # @precondition(lambda self: bool(self.all_groups))