diff --git a/docker/tests/test_vault.py b/docker/tests/test_vault.py
--- a/docker/tests/test_vault.py
+++ b/docker/tests/test_vault.py
@@ -43,8 +43,13 @@
         tfinfo = tarfiles.get(join(dir_id, fname))
         assert tfinfo, f"Missing path {fname} in retrieved tarfile"
         if fdesc["type"] == "file":
-            assert fdesc["length"] == tfinfo.size, f"File {fname}: length mismatch"
-            fdata = tarf.extractfile(tfinfo).read()
+            # symlink has no size in tar archive
+            if not tfinfo.issym():
+                assert fdesc["length"] == tfinfo.size, f"File {fname}: length mismatch"
+                fdata = tarf.extractfile(tfinfo).read()
+            else:
+                # checksum was computed from targeted path for symlink
+                fdata = tfinfo.linkname.encode()
             for algo in fdesc["checksums"]:
                 if algo not in hashlib.algorithms_available:
                     continue