diff --git a/tests/v1/core/test_kv_cache_utils.py b/tests/v1/core/test_kv_cache_utils.py
index d1427f5eaf44..319e6e84fba1 100644
--- a/tests/v1/core/test_kv_cache_utils.py
+++ b/tests/v1/core/test_kv_cache_utils.py
@@ -30,6 +30,16 @@
 # yapf: enable
 
 
+@pytest.fixture(autouse=True)
+def _auto_init_hash_fn(request):
+    hash_fn: Callable
+    if "hash_fn" in request.fixturenames:
+        hash_fn = init_none_hash(request.getfixturevalue("hash_fn"))
+    else:
+        hash_fn = sha256
+    init_none_hash(hash_fn)
+
+
 def make_request(
     request_id: str,
     prompt_token_ids: list[int],
@@ -424,7 +434,6 @@ def test_generate_block_hash_extra_keys_cache_salt():
 
 @pytest.mark.parametrize("hash_fn", [sha256, sha256_cbor])
 def test_hash_block_tokens(hash_fn):
-    init_none_hash(hash_fn)
     parent_block_hash = BlockHash(b"123")
     curr_block_token_ids = (1, 2, 3)
     extra_keys = ("key1", "key2")
@@ -437,8 +446,6 @@ def test_hash_block_tokens(hash_fn):
 
 @pytest.mark.parametrize("hash_fn", [sha256, sha256_cbor])
 def test_request_block_hasher(hash_fn):
-    kv_cache_utils.init_none_hash(hash_fn)
-
     request = make_request(
         request_id="0",
         prompt_token_ids=[_ for _ in range(6)],
@@ -461,8 +468,6 @@ def test_request_block_hasher(hash_fn):
 
 @pytest.mark.parametrize("hash_fn", [sha256, sha256_cbor])
 def test_hash_tokens_different_mm_input(hash_fn):
-    init_none_hash(hash_fn)
-
     request1 = make_request(
         request_id="0",
         prompt_token_ids=[_ for _ in range(6)],
@@ -491,8 +496,6 @@ def test_hash_tokens_different_mm_input(hash_fn):
 
 @pytest.mark.parametrize("hash_fn", [sha256, sha256_cbor])
 def test_hash_request_tokens_no_mm_inputs(hash_fn):
-    kv_cache_utils.init_none_hash(hash_fn)
-
     request = make_request(
         request_id="0",
         prompt_token_ids=[_ for _ in range(6)],
diff --git a/tests/v1/core/test_prefix_caching.py b/tests/v1/core/test_prefix_caching.py
index 659d768bcf2e..3cf9d9369676 100644
--- a/tests/v1/core/test_prefix_caching.py
+++ b/tests/v1/core/test_prefix_caching.py
@@ -25,6 +25,16 @@
                                         KVCacheGroupSpec, SlidingWindowSpec)
 
 
+@pytest.fixture(autouse=True)
+def _auto_init_hash_fn(request):
+    hash_fn: Callable
+    if "hash_fn" in request.fixturenames:
+        hash_fn = init_none_hash(request.getfixturevalue("hash_fn"))
+    else:
+        hash_fn = sha256
+    init_none_hash(hash_fn)
+
+
 def make_request(
     request_id: str,
     prompt_token_ids: list[int],
@@ -105,7 +115,6 @@ def make_kv_cache_config_hybrid_model(block_size: int,
 
 @pytest.mark.parametrize("hash_fn", [sha256, sha256_cbor])
 def test_prefill(hash_fn):
-    init_none_hash(hash_fn)
 
     block_size = 16
     manager = KVCacheManager(
@@ -736,7 +745,6 @@ def test_cache_blocks(hash_fn):
     This is a unit test that tests the correctness of the _cache_full_blocks
     function of KVCacheManager.
     """
-    init_none_hash(hash_fn)
 
     block_size = 4
     block_pool = BlockPool(
@@ -849,7 +857,6 @@ def test_mm_prefix_caching():
     """
     This tests that the multi-modal prefix caching is correct.
     """
-    kv_cache_utils.init_none_hash(sha256)
 
     block_size = 16
     manager = KVCacheManager(
@@ -942,8 +949,6 @@ def test_cache_key_salting():
     This tests that cache salts are applied during hashing and the cache
     is separated cache as expected.
     """
-    kv_cache_utils.init_none_hash(sha256)
-
     block_size = 16
     manager = KVCacheManager(
         make_kv_cache_config(block_size, 11),