diff --git a/tests-unit/assets_test/conftest.py b/tests-unit/assets_test/conftest.py
index 6325b8e99..4aa20372f 100644
--- a/tests-unit/assets_test/conftest.py
+++ b/tests-unit/assets_test/conftest.py
@@ -6,6 +6,7 @@ import subprocess
 import sys
 import tempfile
 import time
+import uuid
 from pathlib import Path
 from typing import Callable, Iterator, Optional
 
@@ -188,9 +189,17 @@ def _post_multipart_asset(
 
 @pytest.fixture
 def make_asset_bytes() -> Callable[[str, int], bytes]:
+    # Salt content per test so it never collides with assets left over from
+    # earlier tests. Delete is now always a soft delete (content is preserved),
+    # so the suite can no longer rely on hard-deleting content for isolation.
+    # Deterministic within a test: the same (name, size) yields the same bytes.
+    salt = uuid.uuid4().bytes
+
     def _make(name: str, size: int = 8192) -> bytes:
         seed = sum(ord(c) for c in name) % 251
-        return bytes((i * 31 + seed) % 256 for i in range(size))
+        body = bytearray((i * 31 + seed) % 256 for i in range(size))
+        body[: len(salt)] = salt[:size]
+        return bytes(body)
     return _make
 
 
@@ -227,7 +236,11 @@ def seeded_asset(request: pytest.FixtureRequest, http: requests.Session, api_bas
     if tags is None:
         tags = ["models", "checkpoints", "unit-tests", "alpha"]
     meta = {"purpose": "test", "epoch": 1, "flags": ["x", "y"], "nullable": None}
-    files = {"file": (name, b"A" * 4096, "application/octet-stream")}
+    # Unique content per test so the seed always creates a fresh asset (201).
+    # Delete is now always a soft delete, so content from a prior test survives
+    # and would otherwise dedup this upload into an existing asset (200).
+    content = uuid.uuid4().bytes + b"A" * (4096 - 16)
+    files = {"file": (name, content, "application/octet-stream")}
     form_data = {
         "tags": json.dumps(tags),
         "name": name,