diff --git a/apps/api/tests/test_docker_sandbox.py b/apps/api/tests/test_docker_sandbox.py
index 9abbefd..4c33763 100644
--- a/apps/api/tests/test_docker_sandbox.py
+++ b/apps/api/tests/test_docker_sandbox.py
@@ -234,7 +234,13 @@ async def test_start_session_mounts_only_the_work_tree(tmp_path):
 
     argv = runner.last_argv
     mounts = [argv[i + 1] for i, token in enumerate(argv) if token == "-v"]
-    assert mounts == [f"{tmp_path}/org1/proj1/work:/workspace"], (
+    # The adapter builds the host path with ``os.path.join``, so the expected
+    # string is built the same way rather than hard-coded with "/" — otherwise
+    # the assertion fails on Windows, where the separator is a backslash. The
+    # security property (exactly one bind mount, and it is the work tree) is
+    # platform-neutral.
+    expected = os.path.join(str(tmp_path), "org1", "proj1", "work")
+    assert mounts == [f"{expected}:/workspace"], (
         "exactly one bind mount, and it is the work tree"
     )
     assert not any("git" in mount for mount in mounts)