Introduce a helper function to initialize all-zeroed kv cache.

PiperOrigin-RevId: 764438981

Author: haozha111

ai_edge_torch/generative/utilities/test_utils.py

@@ -0,0 +1,29 @@
+# Copyright 2025 The AI Edge Torch Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ==============================================================================
+"""Test utils for generative layers."""
+from typing import Sequence
+from ai_edge_torch.generative.layers import kv_cache as kv_utils
+import torch
+
+
+def initialize_kv_cache_all_zeros(
+    kv_shape: Sequence[int],
+    layout: kv_utils.KVLayout = kv_utils.KV_LAYOUT_DEFAULT,
+) -> kv_utils.KVCacheEntry:
+  return kv_utils.KVCacheEntry(
+      k_cache=torch.zeros(kv_shape, dtype=torch.float32),
+      v_cache=torch.zeros(kv_shape, dtype=torch.float32),
+      kv_layout=layout,
+  )